Milan Faces Measles Threat as Single Virus Lineage Drives New Outbreak: Study - Video

Despite high vaccination rates, Milan is seeing a worrying resurgence of measles, driven by a single virus lineage. A recent study in Eurosurveillance reveals that 27 of the 32 confirmed measles cases in early 2025 were linked to genotype B3-suggesting sustained community transmission and a risk of re-establishing endemic spread.

Measles, a highly contagious yet preventable disease, has surged across parts of Europe in recent years. Northern Italy faced outbreaks in 2024 from multiple imported strains. However, this year marks a shift: a single B3 strain, genetically similar to one circulating in Morocco, is spreading locally among unvaccinated adults in Milan and nearby provinces.

"Despite 96% first-dose coverage, immunity gaps in adults-especially those never vaccinated-are creating a pathway for the virus to re-establish itself," researchers warned.

Genetic analysis of throat swabs and urine samples from suspected cases confirmed the dominance of this B3 lineage. Mapping revealed no direct link between most cases and international travel, indicating undetected local spread. The median age of patients was 36.5 years, with many requiring hospitalization—including two with severe pneumonia.

The virus has also spread in hospitals and workplaces, underlining the urgency of immunizing healthcare workers and young adults. Researchers stress the need for enhanced surveillance, better adult immunization, and swift outbreak response.

Reference: Fappani, C., Gori, M., Bianchi, S., Tieghi, L., Colzani, D., Senatore, S., Faccini, M., Pasutto, P., Imeri, L., Vezzosi, L., Castillo, D., Villa, S., Cereda, D., Gioacchini, S., Bucci, P., Fioravanti, R., D’Ugo, E., Baggieri, M., Magurano, F., & Amendola, A. (2025). From multiple measles genotype D8 introductions in 2024 to sustained B3 local transmission in and around Milan, northern Italy, from January to April 2025. Eurosurveillance, 30, 20. DOI:10.2807/1560-7917.ES.2025.30.20.2500315, https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2025.30.20.2500315