Effect of prophylactic paracetamol administration at time of vaccination on febrile reactions and antibody responses in children: two open-label, randomised controlled trials.

Background: Although fever is part of the normal inflammatory process after immunisation, prophylactic antipyretic drugs are sometimes recommended to allay concerns of high fever and febrile convulsion. We assessed the effect of prophylactic administration of paracetamol at vaccination on infant febrile reaction rates and vaccine responses.

Methods: In two consecutive (primary and booster) randomised, controlled, open-label vaccination studies, 459 healthy infants were enrolled from ten centres in the Czech Republic.