RIVM has investigated the effect of paracetamol on the immune system of adolescents. If paracetamol was taken before vaccination, the amount of antibodies was lower than when no paracetamol was taken. This is because paracetamol has a negative effect on the immune system, the body's natural defence system. If paracetamol is taken after the vaccination, the vaccine would be as effective as when no paracetamol had been taken.

Paracetamol is a well-known analgesic, taken worldwide to fight pain symptoms, including following vaccination. Earlier research showed that it is preferable not to administer paracetamol to children before they were vaccinated, because the vaccine then becomes less effective. This new research confirms the same is true for adolescents. The use of paracetamol preceding vaccination, to prevent symptoms that result from the vaccination, should be discouraged.

This research was carried out as part of RIVM Strategic Programme ( SPR Strategic Programme RIVM (Strategic Programme RIVM)). With this programme RIVM is contributing to the development of expertise and innovative research projects, to prepare RIVM for questions that may arise in future.