You are less well protected after one dose of the viral vector vaccine than after initial immunisation with an mRNA vaccine. For better protection, we recommend that between 28 days to 4 months after vaccination with the viral vector vaccine, you supplement the initial immunisation with a dose of an mRNA vaccine from Moderna or Pfizer/BioNTech.
To renew and extend the protection provided by the vaccine, we recommend a booster for anyone aged 18 years and older after initial immunisation with the viral vector vaccine. The booster increases and extends protection against falling severely ill with coronavirus.
We recommend a booster vaccination preferably with an mRNA vaccine (Pfizer/BioNTech or Moderna) from 4 months after full vaccination (initial immunisation), provided this is possible from a medical point of view.
Are you unable to be vaccinated with an mRNA vaccine for medical reasons? Or do you not want to be vaccinated with an mRNA vaccine? Then we recommend you have a booster with the Janssen viral vector vaccine from 2 months after initial immunisation.