Measles in Ugandan Children Under 18 Months of Age: A Retrospective Study of Case-based Surveillance, 2018-2024

Measles remains a significant public health threat in Uganda, with regular outbreaks. The current national immunization schedule offers the first measles-containing vaccine dose (MCV) at 9 months, and a second dose at 18 months. We investigated the epidemiology of measles in Ugandan children aged 18 months and younger.

We analyzed the national measles surveillance data from 2018 to the first quarter (Q1) of 2024, probing the demographic and geographic distribution. We categorized children as under 6 months, 6 to under 9 months, and 9-18 months. Suspected measles cases were classified as clinical, epidemiologically linked, laboratory-confirmed or discarded (not measles).

1316/2274 (57.9%) of the suspected cases were diagnosed with measles. One hundred and forty-nine cases (11.3%; 95% CI: 9.7-13.0) were aged under 6 months, 390 (29.6%; 27.0-32.0) 6 to under 9 months, and 777 (59.0%; 56.0-62.0) 9-18 months. 717/1208 (59.4%; 57.0-62.0) of vaccine-eligible children, with a captured vaccination history, had received at least 1 dose of MCV. 59.5% (95%CI: 55.0-63.0) of measles cases were unvaccinated vaccine-eligible children. Several districts did not achieve the WHO-recommended measles surveillance threshold of at least 2 discarded cases per 100 000 population.

Most measles cases among Ugandan children ≤18 months are unvaccinated. Infants nine to 18 months old comprise most of the measles cases (59.0%; 777/1316). To achieve better control of measles transmission, review of the current vaccination policies with strengthened vaccination and surveillance systems are recommended.