Since the COVID-19 pandemic, more people have been dying per year than expected. This is called excess mortality. There are people who have questions about this. Some people are wondering whether the excess mortality might be a consequence of the COVID-19 vaccinations. RIVM is constantly researching the effects of vaccination. These kinds of studies are complex; the research methods and variations in results are often difficult to explain in ways that everyone understands. This page presents answers to frequently asked questions about excess mortality and the COVID-19 vaccinations.
How does RIVM monitor excess mortality in the Netherlands?
Since 2009, RIVM has been monitoring how many people die in the Netherlands per week. The number of deaths (referred to as mortality) is monitored based on data from Statistics Netherlands (CBS). This enables RIVM to assess how mortality is affected by unique circumstances, such as an outbreak of an infectious disease. RIVM publishes these figures on its website on a weekly basis.
What research has RIVM done on the effectiveness of the COVID-19 vaccinations?
Naturally, RIVM wants to know how effective the COVID-19 vaccinations are. For example, RIVM researches vaccine-induced protection against infection, hospital admission and death. In the past few years, RIVM has carried out a number of studies on the effectiveness of the COVID-19 vaccinations. RIVM publishes the results of these studies on its website and in scientific journals.
What research has RIVM done on the COVID-19 vaccinations and excess mortality?
Over the course of 2021 and 2022, RIVM conducted research on the COVID-19 vaccinations and mortality. RIVM studied how well the vaccinations protect against death from COVID-19. RIVM also studied the risk of people dying of something other than COVID-19 after receiving a COVID-19 vaccination. The first study, covering 2021, is described in chapters 5 and 6 of a report jointly published by RIVM and Statistics Netherlands and in a scientific article. RIVM also published a report on the second study, covering 2022 (in Dutch).
To promote research on this topic by various scientists, the Ministry of Health, Welfare and Sport (VWS) has asked the Netherlands Organisation for Health Research and Development (ZonMW) to make funding available to a variety of research groups. One of these research groups is active at the Netherlands Institute for Health Services Research (Nivel). This group recently published the results of its own study on the correlation between the COVID-19 vaccinations and mortality (in Dutch).
Were all these studies carried out using the same methods?
No. There are various ways to conduct research, which is why it is sometimes difficult to directly compare these studies and their results. Collectively, the studies do offer a more complete overview of the causes of excess mortality and the role of vaccination compared to a single study. Scientific evidence is stronger when it is supported by research results from many different studies indicating the same outcome. The studies show that the risk of hospital admission and death due to COVID-19 is lower for vaccinated people than for unvaccinated people.
What kind of data does RIVM use to study the COVID-19 vaccination, deaths and excess mortality?
RIVM uses a number of different data sources. Statistics Netherlands (CBS) tracks how many people die each week and collects data on the causes of death. RIVM uses that data in its research. In addition, RIVM gathers data on people who have had one or more COVID-19 vaccinations, using a system called the COVID Vaccination Information and Monitoring System (CIMS). This system is used to keep records on whether people have received COVID-19 vaccinations and how many vaccinations they have received, as well as data on their health.
Personal data about vaccinations is only stored in CIMS if people give their permission. Otherwise, the data is stored anonymously. This means that we know how many people did not give permission to store their data and were vaccinated by the Municipal Public Health Services (GGDs), but we do not know their identity. As a result, RIVM can accurately estimate the percentage of the Dutch population that has been vaccinated (vaccination coverage), but we cannot use the anonymous data for studies on how well the COVID-19 vaccinations protect people against hospital admission or death (vaccine effectiveness).
Are you allowed to gather vaccination data from everyone and use it for research?
No. The Ministry of Health, Welfare and Sport (VWS) has decided that people must always first give permission for their data to be shared with RIVM. RIVM can only store and use the data for research once this permission has been granted.
When does RIVM consider someone to be vaccinated or unvaccinated?
A person only counts as vaccinated if they have actually received a vaccination. If they come to the appointment but do not receive a vaccination, they do not count as vaccinated. This can happen, for example, if someone changes their mind about getting vaccinated (cancelled vaccination) or if the vaccine could not be administered (failed vaccination). A person counts as partly vaccinated from the day that the first vaccination was given. In RIVM’s vaccination studies, only people who have not received any COVID-19 vaccinations (or not yet) are counted as unvaccinated.
Is the data reliable?
Yes, the data is reliable, because the data of people who have granted permission for their data to be shared is automatically transmitted to CIMS. However, the CIMS data is not complete: not everyone who has received a COVID-19 vaccination has granted permission for their vaccination to be registered. This makes research more difficult.
Has RIVM deleted vaccination data from the system?
No, RIVM does not delete data from CIMS unless people request deletion of their own personal data. The data used by RIVM depends on the type of analysis performed. For example, researchers need different data to determine the vaccination coverage than how well people are protected by the vaccinations (vaccine effectiveness). For example, the data of people who have died or emigrated is important for research into the correlation between the COVID-19 vaccinations and mortality, but not for calculating the vaccination coverage.
RIVM also uses data on anonymous vaccinations to calculate the vaccination coverage, since the latest vaccination coverage is based on people currently living in the Netherlands. As a result, there is a difference between the number of vaccinations used to determine the latest vaccination coverage and the number used for studies into vaccine effectiveness. For the purpose of researching vaccination effects, RIVM uses all the vaccination data stored in CIMS, including the data of people who have since died or moved abroad. Anonymous vaccinations cannot be used in RIVM research on vaccination effects.
Is it true that the vaccination data of people who died shortly after receiving a COVID-19 vaccination is not stored in CIMS?
No, that is not true. All vaccinations administered by the Municipal Public Health Services (GGDs), GPs or nursing homes are registered in CIMS. Transmission and registration of vaccination data are unrelated to the time of someone’s death.
Are vaccinated people healthier?
Research shows that people who are vaccinated are often healthier than people who are not. They are less likely to have symptoms and become ill. This is called the Healthy Vaccinee Effect. Moreover, people who are seriously ill are not vaccinated during illness, even though they have a more significant risk of dying. Researchers who are studying the effects of vaccines should take this into account. The Healthy Vaccinee Effect may make the vaccines seem slightly more effective than they actually are.
Have people died as a result of their COVID-19 vaccination?
Sadly, a person has occasionally died as a result of the COVID-19 vaccination. This has happened in both the Netherlands and internationally. RIVM has studied the risk of people dying of something other than COVID-19 within two months after receiving the COVID-19 vaccination and compared it to the risk for unvaccinated people. This showed that the risk of dying shortly after receiving a COVID-19 vaccination is comparable to the risk of dying for unvaccinated people.
Is the excess mortality a result of the COVID-19 vaccinations?
No. Studies have shown that people who had the COVID-19 vaccinations actually had a much lower risk of dying. They also had a much lower risk of being hospitalised with COVID-19, even when accounting for different methods or using additional data. This has been confirmed by research in the Netherlands and elsewhere.
Why did more people than expected die in the periods when people could get a COVID-19 vaccination?
More people died in the periods when the COVID-19 vaccinations were available. This is not surprising, because these vaccination rounds took place at times when the coronavirus SARS-CoV-2 and other respiratory infections were circulating widely in the Netherlands. People who had COVID-19 then or had recently recovered were not vaccinated at that time, even though they had a more significant risk of dying from COVID-19.
How is it possible that the risk of dying was higher among vaccinated people in some periods?
There were weeks in which the number of deaths per 100,000 people in some groups was higher for people who had already had one COVID-19 vaccination, compared to unvaccinated people.* This difference disappears when we account for the age of those people. This is not surprising: during the basic series of COVID-19 vaccinations (the primary course consisting of two vaccine doses several weeks apart), the first people who received a COVID-19 vaccination were healthcare workers, and then the oldest and most vulnerable people. In early 2021, therefore, the people who were most likely to have been vaccinated against COVID-19 were vulnerable older people, who were also at a higher risk of dying due to COVID-19 or other causes. If we compare vaccinated and unvaccinated people of the same age, the risk of dying was in fact much lower for vaccinated people than for unvaccinated people.