children(7) COVID-19(4) Ethylmercury(2) MIS-C(2) cerebral palsy(2) Vaccine(2) Influenza(2) Conclusion: Delayed vaccination during the primary vaccination schedule occurs in one sixth of the Dutch children. Efforts to improve compliance should be focused in particular on (2) Developmental outcomes(2) immunization status(2) Vaccines(2) pneumococcus(2) Immunosuppression(2) Tuberculosis(2) respiratory infections(2) Conclusion: Addition of antigens to a vaccine resulted in a higher reactogenicity, but the AEs were in general mild and transient. What is Known: • Assessment of adverse events is (2) acute otitis media(1) gustatory sweating(1) Search volume index(1) sports(1) viral infections(1) typhoid fever(1) immunization(1) antivirals(1) colonisation(1) pediatrics(1) IGRA(1) polio(1) Frey syndrome(1) Transmission(1)