Ongoing measles outbreak, the Federation of Bosnia and Herzegovina, December 2023 to February 2024.

We report on an ongoing measles outbreak in the Federation of Bosnia and Herzegovina with 141 cases notified between week 52 2023 and week 6 2024. Among those with known vaccination status, 97% were unvaccinated and the most affected group is children under the age of 5 years (n = 87) who were not vaccinated during the pandemic years. Sixty-eight cases were hospitalised, the most common complications were measles-related pneumonia and diarrhoea. The sequenced measles viruses from four cases belonged to genotype D8.