Vitamin A and body weight status do not impact humoral immunity against measles, mumps or rubella in individuals 4 to 18 years old: a cross-sectional cohort study in India

BACKGROUND: Ongoing measles outbreaks globally have renewed interest in the role of vitamin A in measles infection. Vitamin A supplementation is recommended for measles disease management, but its impact on the immune response to measles virus (MV) infection or vaccination is unclear. We evaluated the relationships between nutrition, vitamin A status and humoral immune responses to measles, mumps, and rubella (MMR) in vaccinated children. METHODS: Anthropometric measurements, serum vitamin A levels and immune response outcomes were assessed in a convenience cohort of 684 Indian children aged 4-18 years who had previously received ≥2 MV-containing vaccine doses. Nutrition status categories were defined by BMI-for-age z-scores per the World Health Organization (WHO) and Indian Academy of Pediatrics (IAP) standards. Serum vitamin A (retinol) levels were quantified by HPLC; ELISA was used to evaluate MV (n = 684), mumps (MuV) (n = 466), and rubella (RV) (n = 508) IgG antibody (Ab) titers; and a PRMN assay was used to assess MV neutralizing antibody (nAb) titers (n = 681). Associations between nutrition and vitamin A status with MV-, MuV- and RV-specific humoral immune responses were analyzed. RESULTS: Among 684 children, 3.2% were underweight, 14% overweight, 10.5% obese, and 72.2% normal weight. Vitamin A deficiency was relatively rare (3.4%), and vitamin A levels were differentially distributed by BMI z-scores (p < 0.0001). MV IgG Ab and MV nAb titers did not differ by BMI-for-age category (MV IgG Ab: p = 0.77; MV nAb: p = 0.585) or vitamin A deficiency vs sufficiency (MV IgG Ab: p = 0.98; MV nAb: p = 0.25) status. MuV IgG and RV IgG Ab titers were also not affected by BMI categories (MuV: p = 0.215; RV: p = 0.36) or vitamin A status (MuV: p = 0.14; RV: p = 0.23). CONCLUSION: Among vaccinated children 4-18 years sampled from a convenience cohort in southern India, body weight and vitamin A status were not associated with humoral immunity to MV, MuV, or RV, suggesting vitamin A does not play a major role in regulating protective immunity to these three viruses.