Factors Associated with Measles Vaccine Immunogenicity in Children at University Teaching Hospitals, Lusaka, Zambia

BackgroundMeasles poses a significant global public health challenge, particularly in low-resource settings where vaccination coverage is limited. This study examined factors associated with measles vaccine immunogenicity in children aged 2 to 15 years at the University Teaching Childrens Hospital and the HIV Pediatric Centre of Excellence in Lusaka in Lusaka, Zambia. MethodsThis was a comparative analytical cross-sectional study conducted from April to July 2024. Blood samples were collected using a questionnaire that was uploaded in Kobo. Data analysis was conducted in R-studio. Descriptive statistics were conducted to summarize respondent data. Bivariate analysis was computed to test the association between the predictor and outcome variables; multivariate logistic regression analysis was conducted to measure the strength of association using adjusted odds ratios (AORs). The p-value<0.05 was considered significant. ResultsChildren aged 10 to 15 years were less likely to have retained immunity compared to those aged 2 to 4 years (AOR = 0.270, 95% CI [0.114-0.618], p = <0.002). HIV-positive children had lower odds of retaining immunity compared to HIV-Negative children (AOR = 0.290, 95% CI [0.137- 0.594], p = <0.001). Children who were breastfed had lower odds of waning immunity (AOR = 0.336; 95% CI [0.147-0.738], p = 0.007) compared to children who were not breastfed. Residing in Lusaka was associated with lower immunity retention compared to children outside the province; however, this finding requires further investigation with a more representative sample size from areas beyond Lusaka. (AOR = 0.250, 95% CI [0.066-0.859], p = 0.031). ConclusionThese findings show that age, breastfeeding and HIV status significantly affect retention of measles immunity in children aged 10-15 years. Younger, HIV-negative and breastfed children show better immunity retention. These results highlight the protective role of breastfeeding and the need for booster doses to enhance immunity retention, especially for older and HIV-infected children.