It is important that vaccines work well, and offer protection against disease. At the same time, vaccines also need to be safe for your health. This page describes how COVID-19 vaccines work.
Vaccination against the coronavirus SARS-CoV-2
Building protection against serious illness
Vaccination helps the body build protection against severe disease caused by the coronavirus SARS-CoV-2. After vaccination, your body responds very quickly by producing antibodies. These antibody levels keep rising in the days after vaccination, continuing to increase for up to two weeks. If some time has passed since the last vaccination or infection, that protection against COVID-19 grows weaker. A new vaccination helps to boost immunity again.
Building protection against infection
Even after vaccination, you may still get COVID-19. The vaccine only offers partial protection against an infection with the coronavirus SARS-CoV-2. However, the vaccine does offer protection against becoming ill or seriously ill from COVID-19. Because the vaccine offers temporary protection against an infection, it indirectly also helps prevent you from passing the virus to others. This effect is minor and temporary. These findings are from the Vaccination Study on the Coronavirus (VASCO).
Protection if the virus changes
The coronavirus SARS-CoV-2 adapts and changes. Along the way, new variants and sub-variants of the virus emerge. Read more on the RIVM page about Variants of the coronavirus SARS-CoV-2. Often, this does not mean the vaccine is no longer effective. This is because the variants that have been circulating in recent years are all from the same strain and are very similar. The current vaccines also work well against these new variants.
Variants of the virus are subjected to research at the national and international levels to determine how they respond to the COVID-19 vaccines. RIVM also closely monitors changes in the virus. These changes usually involve minimal differences in the virus. Even if a vaccine is slightly less effective against a variant, it can still protect against serious illness and death.If necessary, the COVID-19 vaccines will be adapted in response to these new variants.
How long does a COVID-19 vaccination offer protection?
Protection against infection
A vaccination only offers partial protection against getting COVID-19. Moreover, protection against infection decreases by about 20% to 30% in the first six months after vaccination.
Protection against severe illness
The vaccination does offer effective protection against severe illness, hospital admission and death. This protection remains very effective in the six months following vaccination.
Advisory opinion of the Health Council
Since the virus changes constantly, the Health Council of the Netherlands advises offering an annual COVID-19 vaccination for people who are at higher risk. Each year, the vaccine is adapted to the latest variants as much as possible.
Research on effectiveness of the COVID-19 vaccines
RIVM is conducting research on COVID-19 and vaccination. This includes studies on the level of protection among the population of the Netherlands, the vaccines themselves, the burden of disease (hospital and ICU admission), and human behaviour and vaccination behaviour.
More information about vaccine-induced protection against hospital and ICU admission from COVID-19 is available on the RIVM page about COVID-19 hospital admissions according to vaccination status. Since the start of 2024, RIVM has had more limited access to data on hospital admissions due to COVID-19. As a result, ongoing up-to-date analysis of COVID-19 vaccine effectiveness in preventing hospital admissions is no longer possible as of January 2024. However, RIVM will continue analysing vaccine-induced protection against SARS-CoV-2 infection in the VASCO study. Read more about COVID-19 vaccination and protection against infection and transmission on the RIVM page about COVID-19 research.
How the COVID-19 vaccine works
For COVID-19 vaccination in the Netherlands, an mRNA vaccine is available. For COVID-19 vaccination in the Netherlands, an mRNA vaccine is available. This is the vaccine made by Pfizer/BioNTech (Comirnaty).
What does mRNA mean?
mRNA stands for messenger ribonucleic acid. It serves as an instruction manual for the body.
What does the vaccine do?
The vaccine gives cells in your body the instruction to temporarily copy a small part of the virus: the spike protein that normally covers the exterior of the coronavirus. Your cells only make that protein, never the whole virus that could make you ill. The spike protein is harmless, but your immune system recognises it as a foreign substance. In response, your immune system produces antibodies against this protein.
How does this protect you?
If you encounter the SARS-COV-2 virus later on, your body immediately recognises the spike proteins on the virus. The antibodies that you produced after the vaccination quickly take out the virus. This is how the vaccine helps you to build up protection before the virus can make you very ill. The vaccine trains your immune system in advance, so you have faster, better protection before you have contact with the actual virus.
Why is the spike protein harmless?
The spike proteins that are produced in the body after a COVID-19 vaccination are harmless and are quickly broken down again. The vaccine ensures that your body only makes the spike proteins and does not replicate the virus that could make you ill. In the actual coronavirus SARS-CoV-2, the spike proteins help the virus attach to human cells. That allows the virus to enter the cell and replicate there.
Why might you feel unwell for a bit after the vaccination?
After the vaccination, your immune system starts working to learn how to fight the virus. This could lead to pain at the injection site, elevated temperature or fever, headache or tiredness. These symptoms are normal and usually go away after a few days. You cannot get COVID-19 from the vaccine.
Read more about the Pfizer/BioNTech vaccine. The vaccine information leaflet is provided below.
Package leaflet for the Pfizer/BioNTech vaccine against COVID-19
- Official Dutch package leaflet
- Vaccine factsheet – children aged 6 months to 4 years
- Vaccine factsheet – children aged 5 to 11 years
- Vaccine factsheet – children aged 12 years and older and adults of all ages
There is no gelatine, chicken protein or antibiotics in the mRNA vaccines made by Pfizer/BioNTech.