Influenza is a highly contagious viral respiratory disease that affects millions of people worldwide each year. Annual vaccination is recommended by the World Health Organization to reduce influenza severity and limit transmission through elicitation of antibodies targeting mainly the hemagglutinin glycoprotein of the influenza virus. Antibodies elicited by current seasonal influenza vaccines are predominantly strain-specific. However, continuous antigenic drift by circulating influenza viruses facilitates escape from pre-existing antibodies requiring frequent reformulation of the seasonal influenza vaccine. Traditionally, immunological responses to influenza vaccination have been largely focused on IgG antibodies, with almost complete disregard of other isotypes. In this report, young adults (18-34 years old) and elderly (65-85 years old) subjects were administered the split inactivated influenza vaccine for 3 consecutive seasons and their serological IgA and IgG responses were profiled. Moreover, correlation analysis showed a positive relationship between vaccine-induced IgA antibody titers and traditional immunological endpoints, exposing vaccine-induced IgA antibodies as an important novel immune correlate during influenza vaccination.

Child marriage, defined as union before age 18 years, has detrimental health and socioeconomic consequences. This study examines whether women married as children have a disproportionately higher risk of being obese at adulthood compared to their peers married as adults. Using data from the 2012 and 2017 waves of the Tajikistan Demographic and Health Survey, we matched women aged 25 to 49 years by birth year and month to create four birth cohorts. We fitted multivariable logistic regressions to assess the differential odds of being obese and estimated simultaneous quantile regression models to examine the differences in average body mass index (BMI) between women married as adults and as children within birth cohorts. We found that the adjusted odds of being obese for women married as children were 1.5 (CI: 1.3–1.7) times those of those who were married as adults, after controlling for sociodemographic correlates along with birth cohort and survey wave fixed effects. Results of the quantile regression analyses suggest higher expected BMI levels among women married as children compared to those of women married as adults across different quantiles of BMI. The differences though were more pronounced in the younger cohorts than in the older cohorts.