“If you got Pfizer or Moderna in the first round, it doesn’t really matter which of the two you get now,” says Ben van der Zeijst, emeritus professor of vaccines and vaccinations at Leiden University. “Three times Pfizer is basically just as good as first twice Moderna and now a booster with Pfizer. Or vice versa.”
According to the expert, people who previously received AstraZeneca or Janssen are also well protected with an mRNA vaccine. “It is good that we boost with Pfizer and Moderna, because Janssen and AstraZeneca are slightly less suitable for repeated boosters.”
The Health Council has also advised that both vaccines offer good protection.
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According to Van der Zeijst, these conclusions were drawn after many studies, including by the European Medicines Agency (EMA). “All kinds of combinations and sequences have been studied. The effect is comparable. They also do not differ significantly in terms of side effects.”
In general, the following applies: a week after the booster, you are best protected. After that, the protection gradually decreases.
Age difference
Choosing your own vaccine is not an option, a RIVM spokesperson confirms: “You can indeed not choose. That was not possible in the first round either. The distribution of the two vaccines over the injection locations is mainly determined by availability.”
Professor Van der Zeijst agrees: “It is now about making haste. Allowing exceptions would only stop the matter.”
A distinction is made between age groups, says the RIVM. People between the ages of 18 and 30 are preferably vaccinated with Pfizer; the chance is 3 to 5 times smaller that young people will contract myocarditis (inflammation of the heart muscle). This side effect is rare and occurs in less than 1 in 10,000 doses. Those over 45 usually get Moderna. There are signs that this vaccine boosts immunity in this group slightly more.
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According to professor Van der Zeijst, we may be given a choice in March: the new Novavax vaccine will probably become available then. “Pfizer and Moderna are mRNA vaccines. Some people object to that. Novavax is not an mRNA vaccine, but a protein vaccine. So maybe those people will be able to choose that in the future.”
According to him, the extra regulatory burden on the system would not be too bad. “By that time the booster program will be approximately ready, or at least in calmer waters. That should give room to make that choice possible.”
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