Serum hemagglutination inhibition (HAI) responses elicited by immunization were significantly reduced during pregnancy for 3 different influenza vaccine antigens, a recent study found. Therefore, waning serological responsiveness to influenza vaccination with the progression of pregnancy has important translational implications for when immunization should be optimally administered during pregnancy. Quantitative and qualitative shifts in the serological response to influenza vaccination were evaluated in healthy women throughout the course of pregnancy. Serum was obtained before and after vaccination among 71 pregnant and 67 non-pregnant women during the 2011–12 and 2012–13 influenza seasons. HAI assay was used to investigate anti-influenza antibody responses by comparing pre-vaccine and post-vaccine geometric mean titers (GMTs) between groups for each antigen. Researchers found:
- Post-vaccine GMTs at day 28 were significantly reduced for women vaccinated during pregnancy for A/California (H1N1) in 2011, A/Perth (H3N2) in 2011, and B/Wisconsin in 2012.
- Vaccine responses progressively declined with the initiation of vaccination later in pregnancy.
- Anti-H1N1 IgG1, IgG2, and IgG3 titers were reduced in pregnant women compared to non-pregnant controls, and these titers declined with pregnancy progression.
Schlaudecker EP, Ambroggio L, McNeal MM, Finkelman FD, Way SS. Declining responsiveness to influenza vaccination with progression of human pregnancy. [Published online ahead of print June 22, 2018]. Vaccine. doi:10.1016/j.vaccine.2018.05.117.