Fever Incidence in Infants After Influenza Vaccination

Fever Rates with Influenza Vaccines

Infants aged 6-23 months experience fever in approximately 10-35% of cases within 24 hours after influenza vaccination, which is substantially higher than older children 1
Among children aged 1-5 years, fever occurs in 11.5% after influenza vaccination 2, 3, 4, 5, 6
High-risk infants aged 6 months to 4 years show even higher rates, with fever reported in up to 27% of cases 2, 4, 5, 6

TCV is typically not administered to 6-month-old infants as it is generally recommended for children ≥6 months in endemic areas, but more commonly started at 9-12 months or older 4
No direct comparative data exists for TCV fever rates in 6-month-olds in the provided evidence 4

Acetaminophen 10-15 mg/kg every 4-6 hours can be used for fever management, but routine prophylactic use is not recommended for healthy infants 7
Prophylactic antipyretics are only recommended for infants with a history of seizures or family history of convulsions 7
Fever ≥40.5°C (≥105°F) within 48 hours constitutes a severe reaction requiring VAERS reporting 7
The influenza vaccine cannot cause actual influenza infection—it contains only inactivated viruses 1, 8
Respiratory symptoms occurring after vaccination often represent coincidental illness unrelated to the vaccine 8