Age distribution of COVID patients in hospitals in the Netherlands

This article explains the graphs showing the age distribution of COVID patients admitted to hospital (including ICU) , and to ICU .

The graphs show the age distribution of hospital and ICU admissions from the start of the epidemic up to the present time. They show the number of persons per 1 million people admitted in a given week, by age group. We calculate the numbers per 1 million people in order to be able to compare the various age groups with one another (for an example of this type of calculation see ‘Explanation of the data presented’ under Hospitals and Intensive Care Units ). Each line in the graphs represents an age group. The dotted line shows admissions for all age groups combined, per 1 million people.

First and second waves

The higher the line, the more people who were admitted that week. The line clearly shoots up during the first wave (March 2020) and second wave (November 2020 to January 2021) of infections. During the first wave the line dropped rapidly, but during the second wave we can see that that was not the case.

Differences between the two graphs

The first graph shows the ages of people admitted to hospital in a given week, including those admitted directly to ICU. The second graph shows only those admitted to ICU in a given week. This also includes people who were already in hospital with COVID-19, and who became so ill that they had to be admitted to ICU. If you click on the buttons above the graph, you will be able to view a particular age group separately or compare two or more groups. By comparing the line of an age group with the dotted line, you can see if that age group was admitted to hospital or ICU more or less often than the average. You will also be able to see if the age distribution changes over time.

More serious illness mainly in older people

It is striking that both graphs show that people aged 50 and over end up in hospital relatively more often than younger people (from 0 to 49 years). This shows us that age plays a role in the severity of the disease. In other words, older people are at higher risk of becoming seriously ill after being infected with coronavirus. This is why older people, along with vulnerable people, are vaccinated earlier than other groups. After being vaccinated people can sometimes still carry the virus, but usually they will not become seriously ill.

Vaccination is effective

From mid-February the effect of vaccination has become visible in the number of new hospital admissions in the age groups that were vaccinated first. We can see that the line is still rising in most age groups, except in the age groups 80-89 and 90 years and older (see illustration below). This fall is due to the fact that people in these groups have had at least one dose. For this reason, the likelihood that they will end up in hospital due to coronavirus is much smaller. Here we can clearly see the initial effect of vaccinations in the number of new hospital admissions.

Difference between hospital and ICU admissions in the elderly

The age distribution of the total number of hospital admissions for most age groups follows the same trend as for the ICU. However, the lines representing the age groups 80-89 years and 90 years and older show a difference. Here, the line showing admissions to ICU is lower than the line showing the total number of hospital admissions. This is probably because very few seriously ill people of advanced years with severe underlying disease are admitted to ICU.

Expected fall in number of admissions

The number of people being vaccinated against coronavirus is growing fast. This means that increasingly fewer people will become severely ill due to coronavirus, and therefore the number of admissions to hospital and ICUs will also fall. We are already seeing this in the oldest age groups. The next groups in which we are expecting to see this effect are people aged from 70 to 79 years, followed by people aged from 60 to 69 years. When enough people have been vaccinated, we expect all the lines to show a downward trend.