If the recombinant influenza vaccine (RIV4, Flublok Quadrivalent) was given inadvertently to a person younger than 18 years, can it be counted? Would there be any adverse side effects from this error?

RIV4 is not licensed for people younger than 18 years of age, so there are no data regarding safety and efficacy in this age group. However, no serious side effects would be expected. The dose does not need to be repeated. Even if no adverse reaction occurs, vaccine administration errors like this should be reported to the Vaccine Adverse Events Reporting System (VAERS) at www.vaers.hhs.gov.