Key Points

• Since January 1, 2026, 12 cases of measles have occurred and been reported (i.e., 12 new cases in January). The number of reported cases is very low and lower than that of January 2025 (68 cases).

• Among these cases, 4 were hospitalized (including 1 in intensive care), and 1 case developed a complication (including 1 case of pneumonia and 0 cases of encephalitis). No deaths have been reported.

• The median age of cases is 21.9 years. The three most affected age groups are adults aged 20–24 (3 cases), infants under one year of age (2 cases), and adults aged 25–29 (2 cases).

• Among the individuals targeted for vaccination (aged over one year and born since 1980), for whom vaccination status was known (n=7), 5 were unvaccinated or incompletely vaccinated, and 2 had received two doses.

• Seven departments in France (7%) reported at least one case during the period; none were reported in the overseas territories. The departments that reported more than one case are: Savoie (3 cases), Paris (3 cases), and Essonne (2 cases).

• During the period, 3 clusters of cases (groups of epidemiologically linked cases) were reported to the Regional Health Agencies (ARS) (provisional, unconsolidated data) for a total of 6 cases. None of these clusters included 5 or more cases. One cluster is still active in Auvergne-Rhône-Alpes at a ski resort.