AdimFlu-S(®) influenza A (H1N1) vaccine during pregnancy: the Taiwanese Pharmacovigilance Survey.

BACKGROUND: This study evaluated the incidence, nature, and seriousness of adverse drug reactions (ADRs) occurring after AdimFlu-S(®) influenza A (H1N1) vaccination in pregnant women was administered.

METHODS: This is a retrospective cohort study. Between October 2009 and February 2010, 198 pregnant women who had received the AdimFlu-S(®) influenza A (H1N1) vaccine during pregnancy and 198 age-matched pregnant women who had not received influenza vaccine were included and recorded. The pregnancy outcome and maternal adverse effects were extracted from chart reviews. Infant health status data were followed up until 8 weeks post-partum.

RESULTS: During the observation period of each cohort, four subjects (2.0%) in the exposed group experienced vaccine-related adverse events that were mild in severity. A total of 17 women (8.6%) in the vaccine exposed group and 40 women (20.2%) in the unexposed group underwent at least one adverse effect during their pregnancy. A total of 72 infants (35.6%) in the exposed group and 101 infants (49%) in the unexposed group had at least one adverse event within 8 weeks after they were born (p<0.05). The adverse events experienced by the women and their infants were not increased when the vaccine was administered during the first trimester. There were no significant differences between these two groups with regard to preterm delivery rate and stillbirth rate.

CONCLUSION: AdimFlu-S (®) influenza A (H1N1) vaccine is safe for pregnant women and their infants.