Simultaneous or Sequential Administration of Influenza Vaccine Relative to Other Scheduled Vaccines :

Parents are often concerned about the number of vaccines recommended to be given at a time. Families may request either staggering the vaccines over multiple visits or foregoing a key vaccine. One question that comes up is whether simultaneous administration of the diphtheria-tetanus-acellular pertussis (DTaP) vaccine, pneumococcal conjugate vaccine, and inactivated influenza vaccine (IIV) vaccine increase the risk of fever than if the IIV vaccine was given at another time? Walter et al (10.1542/peds.2019-1909) randomized children ages 12-16 months to either get all 3 vaccines on the same day (n=110) or separate the IIV (n=111) and give it two weeks later monitoring children on both schedules (simultaneous and sequential) for 8 days after each vaccine visit for fever or other adverse events. The good news is that there was no increase in fever occurrences after simultaneous vaccination compared to sequential administration of the IIV separate from the DTaP/PCV vaccines. In fact, there was more fussiness noted in the sequential group following the IIV vaccine given separately than when given simultaneously. Neither group sought additional medical care over the 48 hours post-vaccination even if fevers did occur. The results are reassuring and will hopefully help you reassure families about the importance of timely IIV vaccination.