Nearly all vaccines have been reported to be associated with fainting (syncope). Post-vaccination syncope has been most frequently reported after three vaccines commonly given to adolescents (HPV, MenACWY, and Tdap). However, it is not known whether the vaccines are responsible for post-vaccination syncope or if the association with these vaccines simply reflects the fact that adolescents are generally more likely to experience syncope.
Syncope can cause serious injury. Falls that occur due to syncope after vaccination can be prevented by having the vaccinated person seated or lying down. The person should be observed for 15 minutes following vaccination. For additional information about vaccination-associated syncope, see Immunize.org’s clinical resource, Vaccination-Related Syncope: Information for Healthcare Personnel at www.immunize.org/catg.d/p4260.pdf.