Minimum Interval Between Influenza Vaccines

Age-Specific Dosing Requirements

The American Academy of Pediatrics recommends that children aged 6 months through 8 years receiving influenza vaccine for the first time or who have not previously received at least 2 total doses of influenza vaccine require 2 doses separated by at least 4 weeks (for IIV) or at least 6 weeks (for LAIV) during their first season of vaccination for optimal protection 1, 2, 3, 4
The Centers for Disease Control and Prevention (CDC) guidelines state that children in this age group who have previously received at least 2 total doses of influenza vaccine (separated by at least 4 weeks) before July 1 of the current season require only 1 dose 3, 4, 5
The CDC recommends that children requiring 2 doses should receive their first dose as soon as vaccine becomes available to allow the second dose to be administered at least 4 weeks later, ideally by the end of October 3

The CDC recommends that pregnant persons can receive influenza vaccine at any time during pregnancy (any trimester) and only inactivated influenza vaccine (IIV) or recombinant influenza vaccine (RIV) should be used; LAIV is contraindicated during pregnancy 3, 4
The CDC guidelines state that immunocompromised patients should follow the same minimum interval of 4 weeks and inactivated vaccines are preferred over live attenuated vaccines for patients on immunosuppressive therapy 3, 7

The CDC recommends that children and adults aged 9 years and older only need 1 dose of influenza vaccine per season, regardless of vaccination history 3, 4, 5
The CDC states that there is no minimum interval requirement between annual doses for this age group, as only one dose per season is recommended 3