Pertussis immunity in pregnant women and factors associated with seronegative status

Abstract

Despite high level of vaccination coverage, pertussis remains a serious problem of modern medicine. Pertussis cases are registered among infants, adolescents, and adults. Infants younger than three months of age have the highest rate of serious clinical pertussis course. Transplacental transfer of pertussis-specific antibodies induce protection against infection. The available data regarding anti-pertussis antibody level in pregnant women in Russia remain sparce. To evaluate the humoral immunity to Bordetella pertussis in pregnant women and factors associated with seronegative status, we performed a cross-sectional study with 388 participants. SeroPertussis IgG (Israel) ELISA kit was used to quantitate antibodies against pertussis toxin/hemagglutinin. Binary logistic regression analysis was performed to assess factors associated with seronegative status. The median age of the subjects was 30 years old, more than half of which (51.3%) provided no verified pertussis vaccination data so that their children will not receive transplacental anti-infectious immunity. Gestational age was significantly associated with seronegative status. Compared to women tested during the first trimester, participants in the third trimester of pregnancy were more likely to be seronegative against pertussis. The odds of being susceptible rose with increased gestational period (p < 0.01 for linear trend). Age, number of pregnancies and vaccination status revealed no impact on significant differences between seropositive and seronegative subjects. Pertussis booster vaccinations for preschool children, adolescents and healthcare workers dealing with pregnant women and neonates as well as cocoon vaccination strategy and vaccination during pregnancy were necessary to be implemented to protect infants against pertussis.

Keywords

• immunity
• pertussis
• pregnancy
• vaccination
• antibodies
• seroprevalence