Epidemiology of measles infection in Namibia, 2020-2024

Introduction: Despite efforts towards measles elimination, Namibia continues to report outbreaks and cases of measles. The World Health Organization estimates that 9.6 million measles cases and 128,000 deaths were reported worldwide in 2019, 50% of which occurred in Africa alone. Namibia reported 75 cases and 0 deaths in the past five years from 2020 to 2024. We described the epidemiology of measles infection in Namibia from 2020 to 2024. Methods: A retrospective secondary data analysis of measles infections reported in the national measles line list between January 2020 and April 2024 was conducted. We calculated frequencies, incidence rates, proportions, and time series to identify trends and seasonality. Data were cleaned in Microsoft Excel and analysed in SPSS version 25 and Datawrapper. The data were visualised using tables, graphs, and maps. Results: A total of 75 cases recorded in the national measles line list between January 2020 and April 2024 were analysed in this study. The median age was 5 (Interquartile range: 2.5 – 9) years. Half of the cases (50.1%) were aged 0-4 years old. There was a steady increase in measles incidence in Namibia, with a rate of 0.73 per 100,000 in 2024 (0.73/100,000). A seasonal trend was observed, with most cases occurring between April and May of each year. Among the cases, 44% were vaccinated, 40% had unknown vaccination status, and 16% were unvaccinated. The highest incidence rates were reported in the Erongo region in 2024 (6.24/100,000), followed by those in the northern regions. Conclusion: The burden of measles infections was observed among children aged 0-4 years, and during the winter season. With a steady increase in the number of cases in the country, measures for successful elimination need to be strengthened to prevent outbreaks and ensure that Namibia remains on track with its elimination targets.