By now, most people have built up immunity to the coronavirus SARS-CoV-2 as a result of vaccination and/or infection. Not everyone becomes ill or develops severe symptoms from a first or subsequent SARS-CoV-2 infection that causes COVID-19. The symptoms are often mild, and sometimes people have no symptoms at all, but others have long-term symptoms (post-COVID). The expectation is that COVID-19 will not disappear, but will have surges every year, for example in winter. The question is why this is happening when so many Dutch people have been vaccinated or have previously had COVID-19.
Over the past few years, assisted by the PIENTER Corona Study, RIVM investigated immunity to SARS-CoV-2 among the general population in the Netherlands. In this study, we collected information about antibodies in the blood of people of various ages, distributed throughout the Netherlands. These antibodies indicate whether a person has been vaccinated and/or recently had a SARS-CoV-2 infection. By monitoring antibody levels in participants, we learned more about protection against the virus and how long that protection lasts.
The study
The PIENTER Corona Study was launched at the start of the pandemic in April 2020 with 3200 participants, and another 4500 participants were added in June 2020. Many of these 7700 participants took part in multiple rounds of the study. The research project was extended and new participants were invited in autumn 2021, joining the existing participants. As a result, it was possible to, for example, monitor the duration of coronavirus immunity at all ages even more effectively.
The thirteenth and final round took place in autumn 2024.
Publishing results
After each round of research, RIVM publishes a summary of the results on the website. Since various steps are involved in the process leading from the start of a round to the final research results, this always takes some time:
- We invite participants to take part in a new round of research, and ask them to send in a blood sample and complete a survey.
- Within about a month, most of the blood samples have arrived at RIVM.
- We examine the blood samples in the laboratory to check for antibodies and determine antibody levels.
- We perform quality checks on the laboratory tests.
- The data from the completed surveys is processed into a database.
- Then we compile the data from the surveys and the research data from the laboratory tests.
- The definitive analyses and results are processed in scientific articles. Then a summary of the key results is published on the RIVM website.