TIME TO MEASLES VACCINATION AND ITS DETERMINANTS AMONG CHILDREN AGED 12-23 MONTHS IN MOZAMBIQUE: A SURVIVAL ANALYSIS

  • Edmilson Filimone1,2*,
  • Edy Chissaque1,
  • Sheyla Cassy2,3,
  • Esperança Guimarães1,
  • Assucênio Chissaque4,
  • Orvalho Augusto5,6,7
  1. Instituto Nacional de Saúde, Mozambique;
  2. Universidade Eduardo Mandane, Mozambique;
  3. Universidade Nova de Lisboa, Portugal;
  4. Elizabeth Glaser Pediatric AIDS Foundation, Mozambique;
  5. Department of Global Health, University of Washington, Seattle, WA 98105, United States of America;
  6. Centro de Investigação em Saúde da Manhiça, Manhiça 12th Street, Distrito da Manhiça, Maputo Province 1929, Mozambique;
  7. Faculdade de Medicina, Universidade Eduardo Mondlane, Maputo City, Mozambique.

*corresponding author: filimone.edmilson@gmail.com

Background: Measles remains one of the leading causes of vaccine-preventable diseases worldwide, with an estimated 12 deaths every hour, mostly among children under five. Since its introduction in 1974, the measles vaccine has saved nearly 94 million lives, more than any other EPI vaccine. In 2024, Mozambique experienced a severe outbreak with over 340 confirmed cases in the northern region. Timely vaccination is critical, as delays increase susceptibility and risk of outbreaks. This study assessed the time to measles vaccination and associated factors among children aged 12-23 months in Mozambique.

Methods: We conducted a cross-sectional analysis using nationally representative data from the 2022-23 Mozambique Demographic and Health Survey. A total of 1807 children aged 12-23 months were included. Weighted descriptive statistics summarized the prevalence of early, timely, and delayed vaccination. Kaplan-Meier estimates were used to calculate the median age at first measles dose. Factors associated with time to vaccination were identified using Cox Proportional Hazards Regression, with results presented as hazard ratios (HR).

Results: The median time to first measles vaccination was 13 months (95% CI: 9.5-16.5). Among children 12–23 months, 79.0% (95% CI: 75.5-82.2) were vaccinated on time, 13.8% (95% CI: 5.4-9.4) delayed, and 7.2% (95% CI: 10.9-16.9) early. Timely vaccination was more likely among children of mothers with higher education (HR=1.29; 95% CI: 1.03-1.77), households in the highest wealth quintile (HR=1.57; 95% CI: 1.04-2.35), those with four or more antenatal visits (HR=3.88; 95% CI: 2.02-7.45), and households with more than two under-five children (HR=3.94; 95% CI: 1.37-11.3). Children living out of the capital city Maputo were less likely to be vaccinated.

Conclusion: In Mozambique, half of children experience a one-month delay in measles vaccination, creating vulnerability to outbreaks. Addressing socioeconomic inequalities and strengthening antenatal care could improve timely vaccination and reduce measles risk.

Keywords: Timeliness, Immunization, Measles, Survival Analysis