Kinetics of Hemagglutination-Inhibiting Antibodies Following Maternal Influenza Vaccination Among Mothers With and Those Without HIV Infection and Their Infants

Abstract

Background: We evaluated the immunogenicity of trivalent inactivated influenza vaccine (IIV3) in pregnant women with and those without human immunodeficiency virus (HIV) infection and the persistence of hemagglutination-inhibiting antibodies in mothers and infants.

Methods: Antibodies were measured before vaccination, 1 month after vaccination, at delivery, and at postpartum week 24 in mothers and within 1 week of birth and at 8, 16, and 24 weeks of age in infants.

Results: We enrolled 98 HIV-uninfected and 100 HIV-infected pregnant women, including 93% with a CD4(+) T-cell count of ≥ 200 cells/µL. Compared with HIV-uninfected women, HIV-infected women had lower seroconversion rates (ranging from 63%-92% vs 36%-40%), lower antibody titers through postpartum week 24, and overlapping antibody half-lives (ranging from 106-121 vs 87-153 days). Infant titers were lower than the maternal titers within 1 week of delivery, regardless of vaccine strain and HIV exposure status. Compared with HIV-unexposed infants, HIV-exposed infants had a similar transplacental influenza virus antibody transfer ratio, lower titers, and a lower frequency of titers ≥ 1:40 (ranging from 82%-95% vs 43%-79%) at birth and higher antibody half-lives (ranging from 43-45 vs 56-65 days).

Conclusions: Compared with HIV-uninfected pregnant women, HIV-infected pregnant women had lower antibody responses and persistence. Compared with HIV-unexposed infants, HIV-exposed infants had lower antibody levels at birth but similar antibody levels after 8 weeks of life. Early IIV3 administration during pregnancy did not decrease antibody titers among infants at birth.

Keywords: HIV; immunogenicity; influenza vaccine; pregnancy; transplacental antibody transfer.