Frequently asked questions

The dashboard presents a variety of data that give us an idea of how we are managing the COVID-19 epidemic. In this section we give an answer to frequently asked questions. More information about the dashboard can be found here.

Vaccinations

The figures for the reported number of vaccines administered are incomplete. This is because the registration systems used by care institutions and GPs are not yet linked to RIVM’s own COVID Vaccination Information and Monitoring System (CIMS). RIVM estimates the number of doses administered as accurately as possible, based on the number of vaccines that it distributes to each of the locations where vaccines are administered.

Unfortunately, the data sets delivered to us via automated systems do not yet contain this information.

The two graphs showing the delivery of vaccines concern different things. The graph ‘Delivered and checked doses & doses administered in total’ shows the total number of vaccines that have been delivered and checked. Newly delivered consignments are always checked first. This takes a few days. After they have been checked they become available to be administered and are included in the graph ‘Delivered and checked’. The ‘Deliveries’ graph shows the total number of vaccines delivered or expected on a certain date, i.e. before they have been checked. Therefore, on any given date, the number of vaccines delivered is higher in the ‘Deliveries’ graph than in the ‘Delivered and checked doses & doses administered in total’ graph.

There is another reason why the number in the ‘Deliveries’ graph is higher than in the ‘Delivered and checked doses & doses administered in total’ graph. The ‘Deliveries’ graph also includes vaccines intended for the Caribbean part of the Kingdom (Aruba, Curaçao, St Maarten, Bonaire, Saba and St Eustatius), and the ‘Delivered and checked doses & doses administered in total’ graph does not.

Information about the side effects of the different vaccines is not published on the coronavirus dashboard. The dashboard shows data that helps people understand how the pandemic is developing. The Netherlands Pharmacovigilance Centre Lareb collects reports for the Ministry of Health, Welfare and Sport on side effects of the vaccines used.

At present it is not possible for the dashboard to display the number of vaccinated people who have tested positive or been admitted to hospital because that data is not delivered by the relevant automated systems.

Hospital and ICU admissions

Since the middle of January, we have been showing ‘Hospital admissions over time, by admission date’ in a separate graph. This gives a better picture of when people were hospitalised. It always takes hospitals a few days to report all their COVID-19 admissions. So the figure for yesterday’s admissions will not be complete for another day or two. The number of admissions may therefore continue to rise over the next few days. The graph is updated to include these figures. The last part of the graph is shaded grey to indicate that the figures for these days are not yet complete. They could still increase.

Hospital admissions are reported to us via different sources and they do not all supply their data at the same time. There is often a delay of a few days between the date of admission and the day when this is reported to us. This means we often have to update the more recent figures.

The dashboard is intended to show how the pandemic is developing and to monitor the pressure on the healthcare system. The number of hospital admissions gives an indication of the disease burden of COVID-19 and the pressure it puts on the healthcare system. Of course it’s positive that patients recover and leave the hospital, but it is not information that helps us monitor the pandemic.

Positive tests

It’s true that adding up all the confirmed cases in the municipalities does not always equal the number of confirmed cases in the region. This is because some confirmed cases cannot be attributed to a specific municipality.

The previous graph proved to be rather complicated for many of the visitors to the Coronavirus Dashboard. This graph has now made way for a new graph showing the number of positive tests per age group over time.

The old ‘Distribution by age’ graph showed a breakdown, in percentages, of the most recent daily number of confirmed cases over the age groups, as well as what percentage of the Dutch population fell into each age group. For example, out of everyone who tested positive yesterday, 16% were in their twenties while 13% of the Dutch population are in their twenties.

The new graph shows how many people in a given age group tested positive for coronavirus per 100,000 people. This graph makes it possible to compare age groups over time. For example, 53.8 people per 100,000 people in their twenties tested positive on 31 March 2021 compared to 29.8 people per 100,000 in their sixties on the same day.

Reproduction number

The most up-to-date value of the reproduction number (R) provided on the coronavirus dashboard at any given time is always from at least two weeks ago. Estimates of R using data from less than 14 days ago could provide an indication of what the definitive value may be, but these are less reliable because the data is not yet complete. It is, for instance, impossible to know how many newly confirmed cases will result in hospital admissions in the days ahead. So the R might look ‘old’ but it is the most recent value we have.

The R shown on the website is updated every Tuesday and Friday afternoon at around 15.20, after we receive this data from the National Institute for Public Health and the Environment (RIVM). On Tuesdays, RIVM gives us the R of three Fridays ago. On Fridays we get the R of three Mondays ago.

Deaths

The number of COVID-19 deaths among people younger than 50 is low. To protect people’s privacy, it must be impossible to trace the presented data back to individual people. Dividing these deaths over narrow age groups might result in reporting only one death in a group, and thus in surviving relatives seeing their loved one presented as a statistic. That’s why there is only one age category for COVID-19 deaths among people younger than 50.

Sewage water measurements

The blue bar at the top of the chart is an average calculated over a longer period. The grey bars for each of the locations show the values in the most recent measurements. There are two possible reasons for a big difference between these values. The most recent measurement produces a much lower number of virus particles than the average of older measurements. Or fewer measurements were carried out, for instance due to fewer samples being collected because of the weather. If the last measurement produces a much lower number of particles, this shows up as a deviating value in the chart on the dashboard.

The catchment area of a sewage water treatment plants rarely falls entirely within a single municipality. A plant in one municipality often serves some or all of the inhabitants of other municipalities. From 4 March 2021 the dashboard also shows sewage water monitoring results for municipalities that do not have their own sewage water treatment plant. This is possible by using the measurements from all sewage water treatment plants that serve a municipality. Using the population distribution statistics provided by Statistics Netherlands (CBS), we can attribute the number of virus particles in sewage water to a municipality that does not have its own wastewater treatment plant. The figure presented is per 100,000 inhabitants and can therefore be compared with other municipalities. This new method of calculation produces other values at national, regional and municipal level. More information about how these figures are calculated can be found on this website.

Regional numbers

Coronavirus doesn’t spread uniformly. Sometimes it flares up in one region, while in others the infection rate remains low. If we have an accurate picture of this, we can combat the virus quickly and in a targeted manner. That’s why the data on the dashboard is also broken down by municipality/region. This also helps mayors decide if local measures are necessary.

The situation varies widely, and some regions have been worse affected than others. But the virus can easily spread across the country and that’s why many measures apply nationwide. Sometimes, extra measures are taken in a specific region if there are many extra cases there. These are largely based on input from experts, and consultations with the GGDs and safety regions.

General

An alert value is a kind of ‘alarm bell’, determined by the Ministry of VWS. These alarm bells can go off if a large number of people test positive, fall ill or are admitted to hospital at the same time. It’s been calculated that the healthcare sector would soon be unable to cope if daily hospital admissions for COVID-19 exceed 40 per day for an extended period of time.

The tiles on the dashboard show the term “value of” to indicate the date to which the number refers, while “obtained” is used to refer to the date when the information was received. The purpose of providing this information is to give users a better idea of how up-to-date the data is, which is especially relevant for retrospective indicators. For instance, RIVM publishes the reproduction number (R) twice a week, but the most recent R is always for a date two weeks in the past. “Value of” is followed by that date two weeks ago, and “obtained” by the date on which the most recent R was published (the current week).

In order to compare municipalities, we convert some figures to figures per 100,000 people. We do this so we can better compare large and small municipalities with one another. If we didn’t do this, municipalities such as Amsterdam and Rotterdam would always have high numbers because far more people live there than in smaller municipalities.

Example:
On 3 May 2021, a total of 47 people in Katwijk had a positive test result.
According to figures from the CBS, there were 65,753 people living in Katwijk on that date.
The calculation we then make is 47 / 65,753 * 100,000 = 71.5.
So on 3 May, a total of 71.5 people per 100,000 in Katwijk tested positive.

On 3 May 2021 a total of 455 people in Amsterdam had a positive test result.
According to figures from the CBS, there were 872,757 people living in Amsterdam on that date.
We then make the same calculation: 455 / 872,757 * 100,000 = 52.1.
So on 3 May, a total of 52.1 people per 100,000 in Amsterdam tested positive.

More people live in Amsterdam than in Katwijk, but by calculating the positive test results per 100,000 people we are able to compare the two municipalities. On 3 May 2021 more people per 100,000 inhabitants in Katwijk than in Amsterdam had a positive test result.

Because the number per 100,000 people is a calculated rate and therefore does not express an exact number of people, it can be rounded off to the nearest tenth (one decimal place).