Barbra M. Fisher

Behaviors and perceptions regarding seasonal and H1N1 influenza vaccination during pregnancy.

We examined vaccination rates during pregnancy against both seasonal and pandemic H1N1 influenza and reasons for nonadherence to recommended guidelines during the 2009 through 2010 influenza season. Demographic and vaccination data were collected using a cross-sectional approach. Among 813 postpartum women, 520 (64%) reported receiving the seasonal influenza vaccination and 439 (54%) reported receiving the H1N1 influenza vaccination during pregnancy. Most received vaccinations at their obstetricians office. Major reasons for not receiving vaccination were: not knowledgeable about the vaccine importance (25%), concerns for effects on fetal and maternal health (18% and 9%, respectively), and not knowledgeable about where to obtain vaccination (9%). Reported H1N1 influenza vaccination rates were significantly lower in blacks (37%) compared with non-Hispanic whites, Hispanics, and Asian/other (57%, 59%, and 58%, respectively; P < .0001). Subsequent campaigns for improving vaccination rates in pregnancy should focus on educating patients about vaccine importance and safety.

Pandemic Influenza A H1N1 2009 Infection versus Vaccination: A Cohort Study Comparing Immune Responses in Pregnancy

Background With the emergence of H1N1 pandemic (pH1N1) influenza, the CDC recommended that pregnant women be one of five initial target groups to receive the 2009 monovalent H1N1 vaccine, regardless of prior infection with this influenza strain. We sought to compare the immune response of pregnant women to H1N1 infection versus vaccination and to determine the extent of passive immunity conferred to the newborn. Methods/Findings During the 2009-2010 influenza season, we enrolled a cohort of women who either had confirmed pH1N1 infection during pregnancy, did not have pH1N1 during pregnancy but were vaccinated against pH1N1, or did not have illness or vaccination. Maternal and umbilical cord venous blood samples were collected at delivery. Hemagglutination inhibition assays (HAI) for pH1N1 were performed. Data were analyzed using linear regression analyses. HAIs were performed for matched maternal/cord blood pairs for 16 women with confirmed pH1N1 infection, 14 women vaccinated against pH1N1, and 10 women without infection or vaccination. We found that pH1N1 vaccination and wild-type infection during pregnancy did not differ with respect to (1) HAI titers at delivery, (2) HAI antibody decay slopes over time, and (3) HAI titers in the cord blood. Conclusions Vaccination against pH1N1 confers a similar HAI antibody response as compared to pH1N1 infection during pregnancy, both in quantity and quality. Illness or vaccination during pregnancy confers passive immunity to the newborn.