ABSTRACT
Background: Previous research has shown that socioeconomic and demographic risk factors in children are additive and lead to increasingly negative impacts on vaccination coverage. The goal of this study is to examine if different combinations of four risk factors (infant sex, birth order, maternal education level, and family wealth status) vary by state among children 12-23 months in India and to determine the impact of ≥ 1 risk factor on differences in state vaccination rates. Methods: Using data from the National Family Health Survey (NFHS) conducted in India between 2005 and 2006 (NFHS-3) and 2015-2016 (NFHS-4), full vaccination of children 12-23 months was examined. Full vaccination was defined as receipt of one dose of bacillus Calmette-Guérin (BCG), three doses of diphtheria-pertussis-tetanus vaccine (DPT) vaccine, three doses of oral polio vaccine (OPV), and one dose of measles-containing vaccine (MCV). Associations between full vaccination and the four risk factors were assessed using logistic regression. Data were analyzed by the state of residence. Results: A total of 60.9% of children 12-23 months were fully vaccinated, in NFHS-4, ranging from 33.9% in Arunachal Pradesh to 91.3% in Punjab. In NFHS-4, the odds of full vaccination across all states were 15% lower among infants with 2 risk factors versus 0 or 1 risk factors (OR: 0.85, 95% CI: 0.80-0.91), and 28% lower among infants with 3 or 4 risk factors versus 0 or 1 risk factor (OR: 0.72, 95% CI: 0.67-0.78). Overall, the absolute difference in the full vaccination coverage in those with > 2 vs < 2 risk factors decreased from -13% in NFHS-3 to -5.6% in NFHS-4, with substantial variation across states. Conclusions: Disparities in full vaccination exist among children 12-23 months experiencing > 1 risk factor. Indian states that are more populous or located in the north were more likely to have greater disparities.
ABSTRACT
Measles continues to result in focal outbreaks in India, despite over three decades of universal infant vaccination. The aims of this study were to examine measles immunity in the population of Chandigarh, India, and to compare immunity by vaccination vs. natural infection. In a cross-sectional study of individuals 1-60 years selected from 30 communities within Chandigarh during 2017-2018, measles immunity was assessed using serological surveys. Seropositivity was compared across demographic groups, and by prior history of vaccination and natural history of infection. Among those 1-20 years old, measles seropositivity, and histories of measles vaccination or prior measles diagnosis were separately assessed as outcomes in logistic regression models, with demographic factors as independent variables. Among 1690 participants, 94% were seropositive, and 6% had borderline or negative antibody levels. Of those positive, 30% had prior vaccination, 16% had a history of natural infection, and 54% had an unknown history. Over 50% of individuals among those >20 years old, had unknown history of immunity. In the multivariable regression models, vaccination was more common in younger ages (P < .0001), and in males compared to females (P = .0220), and in those with more education (P < .0001). The majority of the population was seropositive, and seropositivity increased with age. Older age groups were more likely to be protected because of previous natural infection, whereas younger age groups were protected by vaccination. There was inequity in vaccination coverage by gender, and maternal education status.
