Coronadashboard data explained

Value of
On the dashboard we use 'Value of' to indicate which date (period) the figures refer to.

Obtained on
We use 'Obtained on' to indicate the date when we received the data from our sources.

This way we make it clear how up-to-date the data is and when we received it, especially for indicators that look back in time.

For example:
'Value of Thursday 13 April 2023 obtained on Friday 28 April 2023'.

Where do the numbers come from?

The population numbers come from Statistics Netherlands (CBS).

• View the figures on the website of Statistics Netherlands (CBS)

How are the numbers calculated?

To be able to compare municipalities with each other, we convert some figures into figures per 100,000 inhabitants. This way we can compare larger municipalities and smaller municipalities.

Otherwise, municipalities such as Amsterdam and Rotterdam, for example, would always have high figures, because many more people live there than in smaller municipalities.

Calculation example
In Katwijk, 47 residents have had a positive test result out of 65,995 residents. The calculation is 47 / 65,995 x 100,000 ≈ 71.2.
Per 100,000 inhabitants, 71.2 inhabitants in Katwijk had a positive test result.

In Amsterdam, 455 residents have had a positive test result out of 873,338 residents. The calculation is 455 / 873,338 x 100,000 ≈ 52.1.
Per 100,000 inhabitants, 52.1 inhabitants in Amsterdam had a positive test result.

Where do the numbers come from?

In the Netherlands, mergers or divisions of municipalities often take place.

The National Institute for Health and Environment (RIVM) processes municipal reorganizations in the data supplied for the Corona dashboard.

How are the numbers calculated?

We adjust the maps on the dashboard to the changed borders. The figures of municipalities that no longer exist, are added to the figures of the municipalities with which they have been merged.

Where do the numbers come from?

A view on patients
The National Institute for Public Health and the Environment (RIVM) provides the figures on the ages of admitted patients as open data.

Age division of the Dutch population
Figures on the age distribution of the population come from open data from Statistics Netherlands (CBS).

How are the numbers calculated?

A view on patients
The data contains the weekly totals of the admissions that took place in that week per age group. It is supplied by Stichting National Intensive Care Evaluation (NICE) and processed by RIVM. The graphs for hospital and ICU admissions show those weekly totals. To be able to compare age groups, we calculate numbers per 1 million people from a specific age group. We determine the population size per age group on the basis of the CBS classification.

Calculation example
The average of the number of positive tests, of people aged 90 and older, is 26.14 out of 129,831 people aged 90+.
The calculation is 26.14 / 129,831 x 100,000 ≈ 20.13.
Per 100,000 people aged 90+, 20.13 people have tested positive.

By doing this with all age groups, we can compare the groups with each other.
The national average in the age graph is the average of all cases for which the age is known.

When comparing, for example, the age group 90+ with the national average, this national average consists of all age groups including those of 90+.

Adjustments and corrections

The last days in the graph are not yet complete. RIVM supplements the figures with retroactive effect and can also make corrections.

How are the numbers calculated?

Daily figures can give a changing picture due to differences in values. To give a clearer picture of the trend, we also show an average per seven days. This is done by adding up all seven-day reports, dividing by seven.

Calculation example

On Monday, the average over the last seven days is an average from last Tuesday through this Monday.

Where do the numbers come from?

The figures for wastewater testing are supplied by the National Institute for Public Health and the Environment (RIVM) as open data.

How are the numbers calculated?

Wastewater samples are collected at wastewater treatment plants (WWTP) across the country, so that data is available for all of the Netherlands. The samples of untreated wastewater are kept chilled during transport to RIVM. RIVM researchers analyse the samples and determine how many coronavirus particles each sample contains. Three times a week on average for each location, researchers test one sample of wastewater collected over a 24-hour period.

It takes several days before the outcome of an analysis is known. That is why the dashboard does not show measurements from the most recent days.

The number of samples that can be analysed successfully differs from one week to the next. The open data file shows the date and location of successful measurements. If the number of virus particles in a sample is too low to be measured, the value is recorded as 0. This monitoring method is still under development.

In collaboration with the water authorities, Statistics Netherlands (CBS) has mapped out the number of connected residents per WWTP. This enables RIVM to calculate the number of virus particles per 100,000 inhabitants. To be able to compare municipalities with each other, we look at how many virus particles there are on average per 100,000 people. If exactly 100,000 people lived in 1 specific municipality, the average number of virus particles displayed on the dashboard of that municipality x 100 billion.

Adjustments and corrections

Removing extremely high readings from datasets

In a number of cases, RIVM and the Ministry of Health, Welfare and Sport have decided to extract measurements from the open data. The results of these measurements were very high and deviated strongly from the regional and national trends in wastewater research.

Other indicators, such as the number of positive tests, also showed a different picture. It has been extensively investigated by RIVM and remains an ongoing investigation. The RIVM has established a protocol for dealing with these kinds of high values.

6 February 2023 Change in number of measurements per week
RIVM has reduced the number of measurements per location from 4 to 3 per week. This is sufficient to keep an eye on the virus.

30 December 2022 New database of CBS residents
RIVM uses a new version of the database of Statistics Netherlands (CBS), which describes the number of inhabitants per catchment area of waste water treatment plants. The new figures in this version have been retroactively applied to all waste water measurements from 2022.

26 September 2022 Rainfall causes deviations in measurements at all WWTP's According to RIVM, the results of the waster water measurements of Monday, September 26, 2022 do not provide a good picture of the amount of virus particles in the sewer. This is because a lot of rain fell throughout the country while the samples were being taken. Therefore, these measurements will not be published in the open data.

18 August 2022 Removal of high measurements of all data at WWTP Katwoude From 18 August 2022, there will no longer be any wastewater measurement for the Katwoude WWTP. The wastewater measurements of WWTP Katwoude are also no longer included in the calculations with retroactive effect.

4 May - 24 June 2022 No measurement data WWTP Zeewolde
Between May 4 and June 24, 2022, no measurement data are known from the Zeewolde wastewater treatment plant due to technical maintenance.

3 February 2022 Removal of high measurements from dataset

31 August 2021 Deviating measurement location Dinther
On 31 August 2021, the dashboard published a measurement of August 26, 2021 from measurement location Dinther with a very high outcome. This measurement also caused a large increase in the national figures. Because the value was so extreme and RIVM did not find an explanation after quality checks and research, RIVM removed the measurement from the data on September 1, 2021. RIVM has conducted further research into other measurements from the same period. The results of samples from August 25, 2021 and August 30, 2021 are on the dashboard.

4 March 2021 Calculations for municipalities without their own WWTP
From 4 March 2021, the dashboard will also calculate how many virus particles are in the wastewater for municipalities that do not have their own wastewater treatment plant. We do this by using the measurements of the wastewater treatment plants to which these municipalities are connected and by looking at the population figures of Statistics Netherlands. Other calculations were also adjusted at the same time. See the paragraph 'How are the figures arrived at' for the calculation method.

5 October 2020 and 7 December 2020 Closure of location Aalst and Lienden In 2020, two measuring locations were closed and their areas were taken over by two other locations. In the week of October 5 2020, location Aalst was taken over by Zaltbommel, and in the week of 7 December 2020, location Lienden was taken over by Tiel. As a result, before these weeks a reduced number of inhabitants is calculated for the Zaltbommel and Tiel location.

View the population numbers in the table on the CBS website about the inhabitants per WWTP 1-1-2020.

Where do the numbers come from?

Self-reported positive tests
The numbers on the percentage of Infectieradar participants who reported a positive test result, come from RIVM. This data is available as open data and presented on the website of Infectieradar.

How are the numbers calculated?

Self-reported positive tests
Participants of Infectieradar are asked weekly to complete a short questionnaire. This questionnaire asks about complaints that may be related to the corona virus.

For the calculation of the percentage of positive test results, only those participants who have completed at least one questionnaire in that calendar week are taken into account. A calendar week runs from Monday to Sunday. Questionnaires and positive tests of new participants are not included in the first week of their participation.

The results of the submitted nose and throat samples of the self-test study that has been running since September 2022 are also not included in the calculation of the positive percentage.

Where do these figures come from?
The National Institute for Public Health and the Environment (RIVM) supplies open data on the reproduction number. The reproduction number (R) is not an exact value but a reliable calculation.

How are the figures determined?
To calculate the reproduction number R, the number of cases of COVID-19 that increases over time is needed. For this, RIVM uses the number of reported COVID-19 cases per day in the Netherlands. In addition, the time between the first day of illness of a COVID-19 patient and the first day of illness of his or her infector is also examined. Based on the data from the Netherlands, we know that the average time is 4 days. There is an existing method for estimating the reproduction number for this.

The figures on hospital admissions are always a bit behind, because it is not yet clear on the first day of illness of a patient whether that patient will be admitted to hospital. Sometimes reports are passed on or changed a little later. RIVM takes this reporting delay into account. The estimates of the R longer than 14 days ago are reliable. If the R is based on data from less than 14 days ago, the uncertainties are greater. We therefore do not show 'Today's 'R', because the uncertainties are too great for that.

The data used for the calculation of R:

How up to date are the figures?
The most up-to-date value of R provided on the coronavirus dashboard at any given time is always from at least two weeks ago. Calculations of R using data from less than 14 days ago could provide an indication of what the definitive value may be, but are not reliable predictors. The more recent the day, the less reliable the figure is since not all the data for that day is available yet.

Changes in the figures
From 15 March 2023, the reproduction number will be calculated again based on COVID-19 hospital admissions according to the NICE hospital registration. From 13 June 2020 to 14 March 2023, the reproduction number was calculated on the basis of COVID-19 reports to the GGD. However, the number of reports is strongly determined by the test policy, and is less suitable as a basis for calculating the reproduction number due to the adjusted test policy and the closure of the GGD test lanes as of 17 March 2023. Until 12 June 2020, the reproduction number was also calculated on the basis of hospital admissions, but then as reported to the GGD.

Where do the figures come from?
The figures on coronavirus variants are supplied by the National Institute for Public Health and the Environment (RIVM) as open data.

How are the figures determined?
The National Institute for Public Health and the Environment (RIVM) has been studying coronavirus variants in the Netherlands through pathogen surveillance since late 2020. Every week RIVM analyses about 1,500 random test samples containing coronavirus that it receives from various labs across the country.
On the basis of this analysis, RIVM can determine what percentage of infections each variant is responsible for and, from there, predict the speed at which the different variants are likely to spread. This enables RIVM to estimate what percentage of future infections will be caused by which variant. As new data arrives each week, it is checked against these predictions. This helps make future predictions more and more reliable. The figures shown on the Dashboard are not RIVM’s predictions, but rather the data from the pathogen surveillance. Preparing and analysing the samples and processing the data takes time. The figures for the most recent weeks are therefore incomplete and, because of this, we do not show them on the Dashboard. As a result, the percentage for a given variant as reported by RIVM often differs from what is shown on the Dashboard at that time. The media also tends to report RIVM’s predictions.

The data gathered from pathogen surveillance is updated every Friday. Figures may change from week to week compared to what was previously published, generally as a result of changes to the date a sample was collected or other changes related to the sample in the registration system. Data from the most recent weeks is incomplete and is updated in future publications as more information becomes available. In other words, the data on the dashboard is updated retroactively.

Variants on the dashboard
The table on the dashboard shows the variants of concern and the variants of interest. The European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) consider a variant to be a variant of concern if it spreads more easily, makes people more sick or if vaccines are less effective against the variant. A variant of interest is a variant that has been traced to multiple infections in a particular setting or cluster, or that has been detected in multiple countries.

The graph on the dashboard only shows the ECDC variants of concern. These variants are monitored because of their potential risk. RIVM follows the ECDC and the WHO guidelines in this respect. The variants that are not shown separately in the graph are listed in the category 'other variants'.

Chart adjustments
As of 3 September 2021 the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) are no longer designating the Alpha variant as a ‘variant of concern’, but as a ‘variant of interest’. Since that date, the National Institute for Public Health and the Environment (RIVM) has included data on the Alpha variant in the data set as a ‘variant of interest’. On the graph ‘Coronavirus variants over time’, variants of interests are included in the group ‘other coronavirus variants’. The Alpha variant was therefore not shown separately on the graph between 3 September and 28 October 2021. However, because the Alpha variant was previously a ‘variant of concern’ and was the dominant variant for almost 6 months, an exemption has now been made for this variant. As of 28 October the Alpha variant is shown separately in the graph again.

Where do these figures come from?
General data on mortality is provided by the national office Statistics Netherlands (CBS).

How are the figures determined?
Statistics Netherlands (CBS) weekly publishes the total number of deaths and compares this number with the expected number of deaths. Excess mortality occurs when more people die than expected. So expected mortality is the mortality you would expect if there had been no corona epidemic. This takes into account factors as aging and migration and compares it with the seasonal pattern from the years before. The predicted number of deaths per week have been taken from the mortality projections made once every year by Statistics Netherlands.

The expected number of deaths has a bandwidth with an upper and lower limit (interval). Statistics Netherlands only speaks of excess mortality if the number of deaths is above the interval. Within the interval, it may be an ordinary fluctuation.

Change definitions LCPS (National Coordination Center for Patient Distribution)

The LCPS has adapted the definitions. An unlabeled patient is no longer counted as a COVID occupancy as of December 12, 2022 if the patient with an indication of COVID has been admitted and is negative and/or without risk of infection within the same admission period or within the time frame of one month. Previously, unlabeled patients were shown as COVID occupancy.

See more information and open data of LCPS

Where do these figures come from?
Occupancy of bed per day and over time

Figures on occupancy of regular hospital and ICU beds are provided by the LCPS. This data is available in the form of an open data file. As of 1 July 2021, the LCPS bases the weekend figures on (historical) data known to the LCPS.

How are these figures determined?

Occupancy of regular hospital beds
The LCPS registers the number of beds on regular hospital wards that are occupied by COVID-19 patients. Figures from before 1 June 2020 may be less reliable, as the LCPS was still in the process of setting up its registration system at that time.

ICU bed occupancy
The LCPS data set includes both the number of ICU beds occupied by COVID-19 patients, and the number of ICU beds occupied by other patients. The percentage of ICU beds occupied by COVID-19 patients is calculated by dividing the number of ICU beds occupied by COVID-19 patients by the total number of occupied ICU beds. ICU bed occupancy does not include any Dutch patients in German ICUs, as the main purpose of this figure is to show the capacity of Dutch ICUs.

Figures from before 1 June 2020 may be less reliable as the LCPS was still in the process of setting up its registration system at that time.

Differences between the figures
There are differences between the LCPS and NICE registration systems. The LCPS system focuses on bed occupancy (capacity), the NICE system focuses on patients. An increase in occupancy does not fully reflect the number of new patients. When a patient is discharged from hospital, the bed does not immediately become available. It is also possible that one bed may have several occupants over the course of a day. Each of these data sets contains different information and is used for different purposes. These figures are therefore not directly interchangeable.

Where do these figures come from?
Patients per age group over time
The figures on the number of admitted patients in the hospital and the ICU are supplied by the National Institute for Public Health and the Environment (RIVM). This data is available in the form of an open data file.

How are these figures determined?
RIVM uses data collected by Stichting NICE (the National Intensive Care Evaluation Registry). Stichting NICE registers the number of COVID-19 patients in the ICU and regular wards. The number of hospital admissions refers to patients admitted to regular wards as well as those admitted directly to the ICU. Patients can also be admitted outside their region.

The dashboard shows the average number of people with COVID-19 admitted daily to hospital, including the ICU. It is a seven-day rolling average. Because the data for the most recent days is incomplete, they are not used in calculating the seven-day rolling average. The graph ‘Hospital admissions over time’ shows the actual number of hospital admissions (including ICU admissions) by admission date, as well as the seven-day rolling average.

The map with numbers per municipality based on date of admission. Although there are often reporting delays, they are offset by the admission numbers from previous days, which are included. Therefore the map still provides a good overall picture of daily hospital admissions.

The numbers are relative (per 100,000 inhabitants) because of the different number of inhabitants per municipality. The admissions are often reported a few days later.

Differences between the figures

Since October 2020, the LCPS has also been collecting figures on new hospital admissions.There are differences between the LCPS and NICE registration systems. The LCPS system focuses on bed occupancy (capacity), the NICE system on patients. An increase in occupancy only says something about the number of new patients. For example, a bed is not immediately available when a patient is discharged. It is also possible that one bed is occupied by several patients during the day. Both data collections therefore contain different data and serve different purposes. The numbers are not interchangeable.

Changes in the figures
Up to 16 December 2020 the dashboard used data from the OSIRIS database, which is provided primarily by the municipal health services (GGDs). However, OSIRIS suffers from significant underreporting of hospital admissions as the GGDs are no longer always informed when COVID-19 patients are admitted to hospital. The NICE data set is more complete, but its definition of ‘hospital admission’ is also broader. Whereas the OSIRIS data set includes only patients admitted to hospital due to COVID-19, the NICE data set also includes hospital patients who have COVID-19 but who were admitted for another reason.

Correction
Due to a correction in the registration system of the Albert Schweitzer Hospital (region Dordrecht), 355 hospital admissions and 30 ICU admissions spread over the period from January 1, 2021 to July 27, 2021 were incorrectly reported. The numbers are lower in reality. The numbers are retroactively updated on the dashboard on July 28, 2021.

Location of admitted patients
Until 24 November 2021, the figures were based on the reporting date (hospital admissions reported to the NICE Foundation in one day). From 25 November 2021, the dashboard uses figures based on admission date (the date the patient was admitted to hospital).

Change in delivery of data from 1 January 2023

As of 1 January 2023, if a test result is positive, it will no longer be recorded whether a person lives at home or lives in a nursing home.

This information was passed on by the GGDs and was an important source of information at an earlier stage of the COVID-19 pandemic. In the meantime, other monitoring instruments and information sources (such as Infectieradar, sewage and germ surveillance and hospital registrations) have become important or have been further developed.

From 10 January 2023, people who have tested positive will be reported as residents of a nursing home, provided that the postal code of this person corresponds to the location of a nursing home.

The Nursing home locations with positive tests section will continue to be updated. This information will be shown on a this new page about Vulnerable groups and people over 70.

If the epidemiological situation changes and additional data sources are required, the GGDs can be asked to provide additional information.

Where do these figures come from?
The figures on nursing home care are provided by the National Institute for Public Health and the Environment (RIVM). RIVM supplies the figures as an open data file.

How are these figures determined?
Residents testing positive
RIVM counts a person as a nursing home resident if, according to the OSIRIS central database, they are resident in a nursing home or a similar residential care centre for the elderly. When someone tests positive for coronavirus, the municipal health service (GGD) asks if that person is resident in a nursing home or residential care home for the elderly. If this information is unavailable, RIVM determines whether the person is a nursing home resident using the old definition (see below under ‘Changes in the figures’).

Nursing and care homes with positive tests
RIVM has determined the total number of nursing home locations per region using the list provided by Zorgkaart Nederland. RIVM counts nursing homes with the same postcode as one nursing home location. The same method is used to determine the number of locations with a positive test. It is necessary to know the total number of nursing home locations per region in order to calculate the percentage of nursing home locations that are infected. To calculate the total number of nursing home locations nationwide, we add up the totals of all regions.

Average over 7 days
The graph showing the number of confirmed cases among nursing home residents and the graph showing the number of residents who have died shows the average over 7 days.

Changes in the figures since November 2021
The definition RIVM used up to the end of September 2020 to determine if someone who had tested positive was a nursing home resident (see below under ‘Old definition’) resulted in an incomplete number of infected nursing home locations. From 1 July 2020, the GGDs register whether a newly-infected person is a nursing home resident. RIVM has recalculated the figures on the dashboard from 1 July 2020 onwards using this data, which now gives a much better picture of the actual number of infected nursing homes and nursing home residents. For reports of confirmed cases amongst residents without a stated first day of illness, the RIVM determines a calculated first day of illness. This calculation method has been adjusted from 16 July 2021. The figures for the number of infected locations have been retroactively adjusted on the dashboard.

As of November 2021, due to the scaled-down contact tracing, it is not standard checked if people live in an institution. This leads to an incomplete number of positively tested nursing home residents and infected nursing home locations.

Old definition
According to the old definition, a person was considered a nursing home resident if they met one of the following conditions:

In addition, the person:

Where do these figures come from?
RIVM delivers data on the number of vaccine doses administered. The figures on the total vaccination coverage in the Netherlands are the figures that RIVM provides to the European Center for Disease Control (ECDC).

The figures on vaccination coverage per municipality are available as an open data file.

How are these figures determined?

Vaccine doses administered
The number of doses administered is drawn from data that the municipal health services (GGDs) pass on to RIVM. RIVM records the number of doses administered by GGD vaccination centres, hospitals, healthcare institutions and general practitioners (GPs) in its central COVID Vaccination Information and Monitoring System (CIMS). However, the CIMS data is still incomplete, as GPs and institutions have not yet reported a small proportion of the doses that have been administered to RIVM.

Despite the incomplete data, we want to depict the number of vaccine doses administered and the number of people vaccinated as accurately as possible. To this end, the dashboard shows RIVM’s estimates of the number of vaccine doses administered in healthcare institutions and GP practices, and the number of people vaccinated. The estimates are based on the number of vaccine doses that have been delivered to the locations where injections are given.

The calculated number of doses administered in general practices is currently unchanged, as the RIVM is recalculating this number. Once the calculation is complete, the number of doses administered in general practices will be updated.

Vaccination coverage
So far, RIVM bases its figures on the total national vaccination coverage on the calculated number of doses administered. This is because the reported vaccinations in the registration system CIMS were not complete enough earlier. As the vaccination coverage is partly based on calculations, the actual coverage may be slightly different.

The figures for vaccination coverage by age group and vaccination coverage per municipality come from CIMS. RIVM registers in CIMS how many people have started and how many people have completed the primary course of vaccinations.

A primary course has started when someone has had the first corona vaccination. A primary course is completed when someone has had the last necessary dose. Depending on the type of vaccine, this may be immediately after the first dose (Janssen vaccine), after the second dose (other vaccines) or after a corona infection and one dose (other than Janssen). If someone has had the last necessary dose, this person is fully vaccinated. Persons with a immune disorder are being offered a third dose. For this group, the third dose is part of the primary course of vaccines. These people also receive a booster.

Repeat vaccination against coronavirus
This autumn everyone aged 12 and over will be able to get a repeat vaccination against coronavirus with an updated vaccine. This will help to prevent the spread of th virus.
People in at-risk groups and health and care professionals who work directly with patients or clients have priority. They will be invited from 13 September 2022 to make a vaccination appointment. The municipal health service (GGD) will start administering repeat vaccinations to these groups from 19 September 2022. After this, anyone aged 12 and over can get a repeat vaccination. Repeat vaccination can help prevent the spread of coronavirus.
You can get the jab if it has been at least 3 months since your last vaccination or coronavirus infection. You must have completed your primary vaccination series. A primary series is 2 doses of BioNTech/Pfizer, Moderna or Novavax, or 1 dose of the Janssen (Johnson & Johnson) vaccine.

Repeat vaccination against corona helps prevent spread of coronavirus
Coronavirus spreads more easily in autumn and winter. The more people who get a repeat vaccination, the slower the virus will spread.
Repeat COVID-19 vaccination helps:
• protect against severe illness, hospital admission or death due to COVID-19;
• prevent hospitals from becoming overburdened;
• keep businesses open, including restaurants, cafés and gyms, because fewer people are ill.

Order of priority
From 19 September 2022, repeat vaccinations will first be offered to health and care professionals who work directly with patients or clients, and people who have a higher risk of becoming severely ill from COVID-19. From 13 September they will receive an invitation to make an appointment for repeat vaccination.
People who have a higher risk of severe COVID-19 are:
• People aged 60 and over
• People aged 12 to 59 who are eligible for the annual flu jab
• People living in residential care facilities
• People with Down’s syndrome.

We also show what percentage of all adults (18+) have received a booster jab. The booster turnout for the group aged 12 and older is shown as of 24 March 2022. A very high booster turnout in young people aged 12 to 17 is not a government goal. Young people will be offered a booster jab but the decision to get one is theirs (and/or their parents or guardians).

From 22 March 2022, we also show the number of repeat corona jabs. Repeat jabs are offered to groups of people (over-60's, people with a severe immune disorder, people with Down syndrome and people in care homes).

If the vaccination coverage is very high or very low in a certain population group, this can be traced back to individuals. For reasons of privacy, the dashboard in those cases therefore shows 'more than 95%' or 'less than 5%' instead of an exact percentage.

Vaccination coverage by age group and per municipality and number of fully vaccinated people actually higher
The vaccination coverage by age group and per municipality is in reality higher than shown on the dashboard. The reason for this is that CIMS only lists the vaccinations given to people who have given permission to register their vaccination.

Waiting time after last vaccine dose
The dashboard counts someone as having had the primary course of corona jabs immediately after the last vaccine dose was administered. The dashboard therefore does not take into account the waiting time after the last dose. In the Netherlands, there is a waiting period of four weeks for the Janssen vaccine and a waiting period of two weeks for other vaccines. Only then does the vaccination provide sufficient protection against COVID-19 and does it count as a valid corona certificate.

Changes in the figures

New calculation method RIVM
As of 19 January 2021 RIVM publishes a weekly update on the vaccination figures of the Dutch population. These vaccination figures were previously based on the number of vaccinations that the Dutch Public Health Service (GGD) has registered in the CoronIT registration system. These CoronIT figures were supplemented by the number of vaccines that have been delivered to general practitioners, hospitals and institutions (i.e. other than the GGD).

Until 24 May 2022, the vaccination coverage based on these supplied vaccines had to be estimated up to a degree. That's because the registrations in CoronIT weren't fully complete. RIVM is now able to better calculate the vaccination data. This new method uses the national COVID vaccination Information and Monitoring System (CIMS) as a basis for the vaccination figures. RIVM supplements the registered vaccinations in CIMS with the GGD vaccination data. The figures coming from other parties than the GGD (like hospitals) are supplemented and calculated on the basis of the GGD data. In addition, we take into account that one vaccination after a corona infection also counts as having completed the primary series of corona jabs.

In addition, RIVM now uses more up-to-date population figures. Until 24 May 2022, RIVM worked with the population figures of 1 January 2020, this being consistent with how the European Centre for Disease Control (ECDC) uses population figures. The population figures are now updated quarterly by RIVM. Also, RIVM substracts vaccinated people who have died or emigrated. As a result, the vaccination rate of the Dutch population had to be slightly adjusted downward.

The main causes for the downward adjustment are that deceased and emigrated persons are no longer added to the figures, and that the population data are updated more frequently. The new calculation method, which no longer uses estimates based on vaccinations supplied to hospitals, institutions and general practitioners, contributes less to the downward adjustment.

RIVM's calculation method with regard to population figures has consequences for the graph 'Vaccinations over time'. This graph shows the number of vaccinations in the past. Because RIVM is adjusting the figures retroactively, as of 1 January 2020, the new RIVM vaccination figures deviate from the figures shown in the graph. Therefore, the chart is currently not being updated.

Update vaccination data July 2022
Every quarter, RIVM uses the latest population data for vaccination figures. For the figures of mid-July 2022, the current population data of July 2022 were used. The age groups have also been adjusted and the calculation of age has been adjusted to 2022 minus year of birth. These adjustments cause slightly lower vaccination rates. The vaccination coverage of the basic series will decrease by 1% as a result of the adjustments.

Correction number of fully vaccinated people
From November 11, 2021, people who have had corona and one vaccine dose count as having completed the primary course of corona jabs in the 'Vaccinated people' graph. Until this date, they counted among not having completed the primary course.

Vaccination coverage
People who have had one shot after having had corona will also count as having completed the primary course from 22 September 2021 in the figures per municipality and per age group. As a result, these numbers have increased. In addition, a number of Janssen vaccinations that had been counted too much were removed from the data on the same date. As a result, the vaccination rate per age group has decreased somewhat.

Improved data
The GGD has removed appointments that were cancelled or that did not result in vaccination from its data set. It has also corrected the data for people who received doses of two different vaccines. Around 160,000 doses have been removed from the data set. The improved data set includes the data up to and including 8 August 2021. The figures on the dashboard were updated on 10 August 2021.

Administred vaccine doses
From 11 November 2021, it will no longer be possible to estimate how many vaccines have been administered for a first or second vaccination for vaccinations administered by providers other than the GGD (for example, institutions or hospitals). The reason for this is that the estimate of the number of administered first and second shots is based on the number of vaccines applied. With the spread vaccines, no distinction is made between the vaccines for the first and second shots and the vaccines used for the booster shot. It is therefore assumed that no more first and second shots will be administered by other providers as of 11 November 2021.

Where do these figures come from?
Once every three weeks the National Institute for Public Health and the Environment (RIVM) delivers the results of a behavioural survey. This data is available in the form of an open data file.

How are these figures determined?
Every three weeks the RIVM conducts a survey to determine the extent to which people comply with and support the coronavirus measures. Around 5,000 people aged 16 and over participate in this survey.

Changes in the figures
Since the 12th round of the survey, which was conducted from 11 to 17 May 2021, the RIVM has amended the questions about two rules.

Curfew
The curfew was lifted on 28 April 2021. Accordingly, RIVM no longer measures compliance with and support for this rule. On the dashboard we show the figures relating to the curfew up to 26 April.

Stay at home if you have symptoms
Up to and including the 11th round of the survey, RIVM may have incorrectly included some people in the group that ignored the basic rule of staying at home if they had symptoms. These were people who had symptoms suggestive of COVID-19 and who did leave their homes, but only after they had tested negative. In other cases, people may have had an urgent medical reason for leaving their homes without first testing negative. While these individuals may not have stayed at home, they did in fact correctly observe the rule. RIVM has therefore rephrased the question relating to this rule.

Because RIVM has rephrased the question, we only show the data based on the new question on the dashboard. The older data is still available in the RIVM’S open data file.

Work from home if possible
The rule ‘work from home if possible’ was not measured in the 14th round (29 June - 5 July 2021) and the 15th round of the survey (13-19 July 2021), because the measure was temporarily abolished. The rule has been measured again from 16th round of the survey (3-9 August 2021). As of round 19 (5-11 October 2021) the rule ‘work from home if possible’ has been changed to the urgent advice ‘work from home, and at the office when needed’. On the dashboard this has been shortened to: 'work at home if possible'.

Stay 1.5 metres from others
As of round 19 (5-11 October 2021) the physical distancing rule ‘stay 1.5 metres from others’ has been changed to the urgent advice ‘give others enough space’.

Avoid busy places
As of round 19 (5-11 October 2021), the coronavirus rule ‘avoid busy places’ is no longer included in the survey because it has been lifted.

Ensure a good flow of fresh air in house
As of round 19 (5-11 October) the new basic rule ‘ensure a good flow of fresh air in house’ has been added to the list of coronavirus rules in the survey.

Closure of GGD test lanes

The coronavirus has reached an endemic phase and the GGD test streets will be closed as of 17 March 2023. As a result, the data will no longer be updated from 4 April 2023. The page Positive tests is archived.

Where do the numbers come from?

The figures on the number of positive tests are supplied by the National Institute for Public Health and the Environment (RIVM). RIVM also supplies the figures on the ages of people who have tested positive as open data.

How are the numbers calculated?

Number of positive tests
The figure shows the number of positive tests reported to RIVM in the preceding 24 hours, up to 10.00 on the day of publication of the figures. The date attributed to positive tests is the date on which RIVM was notified by the municipal health authority (GGD). This is not the same as the date on which people are tested. The data is organized based on the date the tests were conducted. On average it takes 1 to 2 days before test results are produced.

Doctors and laboratories are required to report cases of infectious disease to the GGD. However, coronavirus tests are also carried out by commercial organisations and individuals. The results of these tests are not always reported to the GGD, or the notification is not counted as the test used does not meet RIVM standards. Commercial testing organisations are required to report positive test results to the GGD. This means that the daily number of confirmed cases reported on the dashboard may not give the complete picture. This should be kept in mind when interpreting these figures.

The percentage of tests that have a positive result is based on tests conducted by the GGD and for which the results are known. The seven-day rolling average is calculated with a two-day delay. This is because the results of tests conducted in the last 48 hours may not yet be available. This way we can be sure that most of the results are available and that the percentage of positive tests is accurately represented.

Part of the notification process is done manually. Sometimes the GGDs will not have reported all newly confirmed cases at the moment that RIVM compiles the figures for the preceding 24 hours. Missing notifications are passed on at a later time. Missing or delayed notifications can skew the daily figures. The rolling average filters out this type of fluctuation, and therefore often gives a better picture of the number of infections.

Positive tests per age group over time
The figures on ages of positively tested persons come from a different data source than the figures on positive tests, because the dataset on positive tests does not contain ages. Different dates are used in the two datasets.

The dates used in the age file are:

The file on positive tests uses the date of notification by RIVM. This date is usually further in the future per positive test result than the dates in the file with the ages. In addition, there are positive test results from people whose age is unknown. There are therefore differences between the graph for the absolute number of positively tested persons and the graph with the ages of positively tested persons.

The graph shows averages over the last 7 days. To be able to compare age groups, we calculate numbers per 100,000 people.

Growth rate
The growth rate (or G rate) is a percentage that expresses the change in the number of positive tests in the last 7 days relative to the number of positive tests in the preceding 7 days. To calculate the growth rate, data must be available for 14 consecutive days (the previous 7 days + the 7 days preceding that).

The growth rate is calculated by the Ministry of Health, Welfare and Sport based on data from RIVM. All historical growth rates are recalculated daily, so that any corrections made by RIVM to the number of positive tests are incorporated into the historical trend of the growth rate. The growth rate is calculated in line with the method used by research institute IPSE Studies. The growth rate was introduced by the Dutch newspaper de Volkskrant.

Adjustments and corrections

RIVM can also retrospectively correct data that has already been published. These corrections are processed in the open data file and incorporated into the dashboard. The data file registers cases at safety region and municipality level. In order to calculate data at national level we add all notified cases together. Some notified cases cannot be linked to a particular municipality/safety region, as this information is missing from the data file. These cases cannot therefore be shown at those levels, but they are included in the national figures.

11 April 2022
As of 11 April 2022, everyone no longer has to go to the GGD for a confirmation test. Target groups that can be tested include healthcare workers and residents of nursing homes. As a result, after April 11, 2022, the number of testers who go to the GGD after a positive self-test will be lower.

7 September 2021
On 7 September 2021, we added an additional notification in the graph "Percentage of GGD positive test results, over time". The percentage of positive tests is no longer clear and unambiguous to interpret and compare over time. This is partly due to a recent increase in testing at walk-in test sites not requiring an appointment for students during introduction weeks, testing of returning travellers, and testing for confirmation after a positive self-test.

1 July 2021
As of 1 July 2021 people who are planning to travel abroad can also be tested at GGD test centres. Before 10 August these people’s test results were included in the same data set as the results of people being tested by the GGD for other reasons. As of 10 August travellers’ test results are no longer included. Around 200,000 test results have been removed from the data set. The figures on the dashboard for the period between 1 July and 10 August have been adjusted accordingly. As a result, the percentage of positive test results in that period is higher than previously indicated. The increase is 2 to 3 percentage points, depending on the day.

Change in delivery of data from 1 January 2023

As of 1 January 2023, if a test result is positive, less information is collected.

This information was collected by the GGDs and was an important source of information at an earlier stage of the COVID-19 pandemic. In the meantime, other monitoring instruments and information sources (such as Infectieradar, sewage and germ surveillance and hospital registrations) have become important or have been further developed.

The CBS data will still be updated on the page Death rate. This continues to provide timely insight into trends in total mortality and is reported weekly on our dashboard.

If the epidemiological situation changes and additional data sources are required, the GGDs can be asked to provide additional information.

Where do these figures come from?

Number of COVID-19 deceased patients
The mortality figures are supplied by the National Institute for Public Health and the Environment (RIVM). This data is available in the form of an open data file.

Deceased COVID-19 patients by age group
The graph with the age distribution at national level is based on an open data file of the RIVM.

How are these figures determined?

Number of COVID-19 deceased patients
This is the number of COVID-19 patients whose deaths have been reported to RIVM in the past 24 hours. The date shown is the date on which RIVM was notified by the municipal health authority (GGD). This may not be the same as the date on which deaths occurred. The actual number of deceased COVID-19 patients is higher than the number of deaths reported by RIVM because there is no requirement to report COVID-19-related deaths.

Deceased COVID-19 patients by age group
Everyone under the age of 50 is put in the same age group because that data can be traced back to individuals due to the small numbers, coupled with the breakdown of COVID-19 mortality on the dashboard.

Change in delivery of data from 1 January 2023

As of 1 January 2023, if a test result is positive, less information is collected.

This information was collected by the GGDs and was an important source of information at an earlier stage of the COVID-19 pandemic. In the meantime, other monitoring instruments and information sources (such as Infectieradar, sewage and germ surveillance and hospital registrations) have become important or have been further developed.

The page Disability care will no longer be updated. Available information will be shown on a new page about Vulnerable groups and 70+.

If the epidemiological situation changes and additional data sources are required, the GGDs can be asked to provide additional information.

Where do these figures come from?
The figures on disability care are provided by the National Institute for Public Health and the Environment (RIVM). RIVM supplies the figures as an open data file.

How are these figures determined?
Confirmed cases among residents
From 1 July 2020, the GGDs registers whether a newly-infected person is resident in a disability care facility. RIVM considers a person to be a disability care home resident if they are registered as such in the central OSIRIS database. If this is not known, RIVM counts the person as a disability care home resident if they are not a health worker and:

Locations
The word ‘locations’ refers to the 2,586 care homes in the Netherlands that are registered by Zorgkaart Nederland as providing residential care to people with disabilities. The total number of locations per safety region is provided by RIVM. Locations with the same postcode are counted as one location. The same method is used to determine the number of infected locations. It is necessary to know the total number of locations per safety region in order to calculate the percentage of locations that are infected. To calculate the total number of locations nationwide, we add up the totals of all safety regions.

Deceased residents
We show the number of deaths among disability care facility residents by the date of death. If we do not know the date of death, which is sometimes the case, we do not show the death on the dashboard.

Average over 7 days
The graph showing the number of confirmed cases among residents and the graph showing the number of deaths among residents shows the average over 7 days.

Changes in the figures
For reports of confirmed cases amongst residents without a stated first day of illness, the RIVM determines a calculated first day of illness. This calculation method has been adjusted from 16 July 2021. The figures for the number of infected locations have been retroactively adjusted on the dashboard.

As of November 2021, due to the scaled-down contact tracing, it will not be standard practice to check whether people live in an institution. This leads to an underreporting of the number of positively tested residents of disability care facilities.

Change in delivery of data from 1 January 2023

As of 1 January 2023, if a test result is positive, it will no longer be recorded whether a person over 70 lives at home or lives in a nursing home.

This information was passed on by the GGDs and was an important source of information at an earlier stage of the COVID-19 pandemic. In the meantime, other monitoring instruments and information sources (such as Infectieradar, sewage and germ surveillance and hospital registrations) have become important or have been further developed.

From 10 January 2023, people over 70 who have tested positive will be reported as residents of a nursing home, provided that the postal code of this person corresponds to the location of a nursing home. This information will be shown on a new page about Vulnerable groups and 70+.

The number of positive test results by age group and 70+ will continue to be updated on the page Positive Tests.

If the epidemiological situation changes and additional data sources are required, the GGDs can be asked to provide additional information.

Where do these figures come from?
The figures on people over 70 living at home are provided by the National Institute for Public Health and the Environment (RIVM). RIVM supplies the figures as an open data file.

How are these figures determined?
For its calculations RIVM uses the test results and mortality data that it receives from the municipal health service (GGD). When someone newly tests positive for coronavirus, the GGD records a number of details, including the person’s age and if they live in a nursing home or disability care home. RIVM calculates the number of new cases among over 70s living at home by first determining the total number of new cases in this age group and then subtracting the number of infections among:

We show the number of deaths among over 70s by the date of death. If we do not know the date of death, which is sometimes the case, we do not show the death on the dashboard.

Number of confirmed cases among the over 70s per 100,000
In order to compare groups of people with one another, we convert some figures to figures per 100,000 people. Likewise for the over 70s living at home. Statistics Netherlands collect data on the number of persons aged 70 and older who live at home (cbs.nl: 'StatLine - Huishoudens; personen naar geslacht, leeftijd en regio, 1 januari' in Dutch only). In the Netherlands, this group comprises around 2.3 million people.

Source and contact tracing scaled down

In the event of a positive corona test, the GGD carried out source and contact research until the end of 2021. The GGD contacted the infected person to find out where they might have become infected and to find out who they had been in contact with. The source and contact investigation will be scaled down in the autumn of 2021. As a result, less and less data is available and the Source and contact tracing page is no longer updated. The maps on this page provided data on source and contact tracing in the security regions up to May 15, 2022.

Where do these figures come from?
RIVM provided these figures as open data.

How are the figures determined?
GGDs performed the source and contact investigation (BCO) in people with a positive test result. The GGDs investigate, among other things, in which situation someone may be infected. The GGDs have named 21 possible situations of infections. For the overview on the dashboard, we divided these 21 situations into 8 categories. The overview below shows the eight categories with the situations that fall under the relevant category.

1. At home and visiting

2. Work

3. School and childcare

4. Healthcare

5. Gatherings

6. Travel

7. Restaurant, café or bar

8. Other

From 5 November 2021, GGDs have been working with a new form of source and contact investigation: customized BCO. With customized BCO it was more common that enough information was available to show the possible situations of contamination on the dashboard.

Just like in the 'old' system, customized BCO also has a phase model. This meant that if there were a lot of infections, the BCO went to a different phase and was carried out in a less extensive way. With customized BCO, the GGD worked with the color codes green, orange and red. In the green phase, custom BCO was fully implemented. Orange meant that BCO was carried out to a limited extent. In phase red, the person who tested positive was only called with the result and no further information.

In contrast to the old system, if one of the 25 GGD regions was in phase green or orange, sufficient data was available to display information about BCO on the dashboard.

Read the GGD press release on tailored contact tracing (in Dutch).

The CoronaMelder app was developed in 2020 to prevent the spread of the coronavirus. The app sends users a warning when they have been in the vicinity of someone who has tested positive for an extended period of time.

Where do these figures come from?
The data for the CoronaMelder app come from the Ministry of Health, Welfare and Sport. This data is available as open data.

How are these figures determined?
Alerts for infection
The dashboard shows how many CoronaMelder users who tested positive alerted other app users that they may be infected. This figure, taken from the GGD portal, is based on the number of codes shared each day.

Number of downloads
We also show how many people have downloaded the CoronaMelder app. This figure is calculated by adding together the daily statistics for downloads via:

CoronaMelder app stopped as of 22 April 2022

Many measures are no longer needed since February 2022. For example, you no longer have to stay at home when you have been near someone with corona and you no longer have to have a positive self-test confirmed by the GGD. That is why the usefulness of the CoronaMelder has been greatly reduced.

The app will therefore stop from April 22, 2022. The app will no longer exchange data with other users of the CoronaMelder, nor with notification apps from other EU countries. The app can be reactivated if the development of the corona virus requires it.

Where do these figures come from?
Data on deliveries and doses in stock is provided by the National Institute for Public Health and the Environment (RIVM). This is not yet available as an open data file.

How are these figures determined?
Deliveries
The ‘Deliveries’ graph on the dashboard shows the number of doses that the Netherlands has received and expects to receive. RIVM assumes that each vaccine vial contains a specific number of doses – BioNTech/Pfizer: 6.9 doses per vial; Moderna: 10 doses per vial; AstraZeneca: 11 doses per vial; and Janssen: 5 doses per vial. This may differ from the manufacturer’s instructions for some vaccines.

These figures include the vaccine doses for the Dutch Caribbean and the vaccine doses that the Netherlands donates to other countries.

Doses in stock per type of vaccine
In the graph ‘Doses in stock per type of vaccine,’ the dashboard shows the total and available stock per type of vaccine at the central storage site. The total stock covers stock that is available and stock that is not yet available. The stock that is not yet available comprises vaccines that still have to be checked.

The size of the stock fluctuates: shortly after a new delivery, the total stock of a vaccine is relatively high; just before the next delivery is released from quality control, the available stock is low.

These figures include the vaccine doses for the Dutch Caribbean and the vaccine doses that the Netherlands donates to other countries.

Where did these figures come from?
Until 9 July the National Institute for Public Health and the Environment (RIVM) supplied data on the number of infectious people twice a week. This data is available as open data.

How are the figures determined?
Someone who is infected with coronavirus can transmit the virus to other people. How long they are infectious for differs from one person to another. The precise number of infectious people is unknown, but RIVM calculates the range within which this number probably lies using data from the Pienter Corona study and the number of hospital admissions.

Changes in the figures
From 1 June 2020 until 12 October 2020 the number of infected people was estimated on the basis of data from the first round of the Pienter Corona study, the number of hospital admissions and the number of confirmed cases. As of 13 October 2020, this figure is estimated using data from the second round of the Pienter Corona study and the number of hospital admissions. In the second round of this study, a larger group of people was tested to find out if they were infected with coronavirus, and more insight was gained into the degree of people’s infectiousness.

From 9 July 2021, RIVM will no longer calculate the number of infectious people for the time being. This figure is based on the number of hospital admissions. More and more people have been vaccinated and fewer people are hospitalized as a result. The difference between the number of infections among people and the number of hospital admissions is increasing. Therefore, the number of infectious people is no longer calculated.

Where do these figures come from?
Until 1 Sepember 2021, the Netherlands Institute for Health Services Research (NIVEL) reported on thursday of each week, the figures from general practitioners on patients with COVID-19-like symptoms. This data is available in the form of an open data file.

How were these figures determined?
Once a week, a representative sample of around 350 GP practices across the Netherlands provided data concerning the symptoms of patients they have seen to NIVEL’s Primary Care Database. Using this data, NIVEL determined the number of patients who have reported COVID-19-like symptoms in the past week. NIVEL determined this on the basis of the diagnostic codes reported by GPs and any additional information provided that is suggestive of COVID-19. These diagnostic codes are:

In order to achieve greater accuracy, each week NIVEL also recalculated the data from the preceding weeks. It also included data that was only published at a later date.