<p><strong>Background:</strong> The persistence of measles immunity in children is influenced by multiple factors, including nutritional status. This study aimed to assess the role of body mass index (BMI) as a proxy for nutritional status in the persistence of measles immunity, alongside other socio-demographic factors, in a pediatric population. <strong>Methods:</strong> A multivariate logistic regression analysis was conducted on 200 children (2-15 years) attending the University Teaching Children's Hospital in Lusaka, Zambia. Immunity retention was measured through IgG serology. BMI represented nutritional status, and the analysis adjusted for key variables such as HIV status, breastfeeding history, sex, and education level. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to determine the association between nutritional status and immunity persistence. <strong>Results:</strong> Children categorized as well-nourished had significantly lower odds of waning immunity (OR = 0.37, 95% CI = 0.16–0.83, p = 0.016). However, for children with over or under malnutrition, the association was not statistically significant (OR = 0.23, 95% CI = 0.03–1.62, p = 0.140). Additionally, HIV-positive status was associated with decreased immunity retention (OR = 0.28, 95% CI = 0.14–0.56, p &lt; 0.001). Breastfeeding was positively associated with immunity persistence (OR = 3.34, 95% CI = 1.53–7.29, p = 0.003), while other socio-demographic factors such as sex and education level showed no significant effect. <strong>Conclusion:</strong> Nutritional status, as measured by BMI, plays a significant role in the persistence of measles immunity among children, with over- and under-nourished children being associated with lower immunity retention. These findings suggest that nutritional interventions may be necessary to improve vaccine efficacy, particularly in populations with high rates of malnutrition or obesity. The results also highlight the need for further investigation into the mechanisms linking nutritional status to immune response and the development of targeted public health strategies to optimize measles immunization outcomes in children.</p><p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0722/a.php" alt="Hit counter" /></p>