Epidemiology of measles cases and phylogenetic analysis of the virus circulated in the Federation of Bosnia and Herzegovina during 2018: implications for elimination efforts.

Aim To present combined measles cases data and phylogenetic analysis of the virus circulated in 2018 in the Federation of Bosnia and Herzegovina (FB&H, the entity of Bosnia and Herzegovina), in order to analyse endemic transmission patterns of circulating strains and its implications for elimination efforts. Methods The data were derived from epidemiological case investigations and laboratory diagnoses based on serology, molecular detection and genotyping of the measles virus. Results During 2018 16 measles cases were reported in FB&H, of which five were classified as laboratory confirmed cases, one was an epidemiologically linked case and 10 were clinically compatible cases. Among them 12 (75.00%) cases were unvaccinated or had unknown vaccination status. The most affected population was up to 14 years of age (13/16; 81.25%). None of the cases was fully vaccinated. Viruses of other genetic lineages had been introduced in FB&H in the recent period. Two virus lineages of genotype B3 were identified. Phylogenetic analysis indicated the presence of a unique sequence of measles B3 virus in FB&H (Sarajevo). Conclusion Further strengthening of measles surveillance system and renewed efforts to increase vaccination levels are necessary to prevent disease and for elimination setting.