Vaccine and Infectious Disease Division

Baby flu

Influenza can be very dangerous for small infants, but the flu vaccine is not given to babies under six months old.  A safe and effective flu shot would be very helpful, as some studies show that this age group has the highest rates of severe illness during flu epidemics.  To address whether flu shots could safely be given to very young infants, VIDI affiliate investigator Dr. Janet Englund and colleagues first performed a study testing the safety of Fluzone, an inactivated influenza vaccine commonly used in the U.S in two-month old and six month old babies, and then went on to study this vaccine in a placebo-controlled study in 1,375 babies aged six to 12 weeks.

The scientists looked at several possible side effects of the vaccine, including fever, reaction at the injection site, and other adverse effects, and found that none of these were more common in babies who received the vaccine versus those who received the placebo.  One infant in the vaccine group had an allergic reaction.  The researchers then looked at flu antibodies induced by the vaccine, and found that the infants produced antibodies to the different flu strains contained in the vaccine, similar to adults and older children who get the shot.

Although the study did not test whether these babies were protected against the flu, their results suggest that Fluzone is safe to give young babies and may help protect this highly susceptible group against serious flu-related illnesses and death.

Percentage of participants with fever or local reactions following first and second doses of Fluzone or placebo.  No significant differences were found between vaccine and placebo groups for any reaction at either dose.

Trivalent inactivated influenza virus vaccine given to two-month-old children: an off-season pilot study.  Walter EB, Englund JA, Blatter M, Nyberg J, Ruben FL, Decker MD; GRC27 Study Team.  Pediatr Infect Dis J. 2009 Dec;28(12):1099-104 

Safety and Immunogenicity of Trivalent Inactivated Influenza Vaccine in Infants: A Randomized Double-Blind Placebo-Controlled Study.  Englund JA, Walter E, Black S, Blatter M, Nyberg J, Ruben FL, Decker MD; the GRC28 Study Team.  Pediatr Infect Dis J. 2009 Nov 19 (Epub);.

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