Background: Live attenuated influenza vaccine (LAIV) is approved for use in eligible individuals 2-49 years of age. There are little data regarding fetal or maternal outcomes after LAIV administration during pregnancy. Although the LAIV prescribing information states that LAIV should be given to a pregnant woman only if clearly needed, rare inadvertent administration of LAIV to pregnant women does occur.
Objectives: To analyze case report data on outcomes after exposure to LAIV during pregnancy.
Methods: Data regarding exposure to LAIV during clinical trials beginning in September 1997 and spontaneous postlicensure reports from 2003 through September 2009 were reviewed. All available information on maternal and fetal outcomes was analyzed.
Results: Exposure to LAIV was identified in clinical trials (n=79) and in spontaneous postlicensure reports (n=39). Of reports that included trimester of exposure (n=89), 71%, 18%, and 11% occurred in the first, second, and third trimesters, respectively. Of the 118 total reports, outcome information was available for 72 cases (mean age, 27; range, 14-40 y), and included 52 live births, 7 spontaneous abortions, 12 therapeutic abortions, and 2 ectopic pregnancies. The 52 live births included 41 infants described as “healthy”, 7 without additional details, 3 premature infants (32-33 weeks gestational age, including twins) and 1 infant with clinodactyly. Four women reported adverse events within 21 days of receiving LAIV, including headache (n=2) and sore throat (n=2). Common complications of pregnancy were also reported, including vaginal bleeding (n=6), placenta previa (n=4), threatened labor (n=4), and abdominal pain (n=4).
Conclusions: In this limited cohort, outcomes after inadvertent administration of LAIV to pregnant women did not suggest any safety signals in the mothers or children. As with all live vaccines, LAIV is not recommended for pregnant women and should not be used unless clearly needed. Sponsored by MedImmune.