Key Points

• From January 1 to March 14, 2025, 180 cases of measles were reported, compared to 83 during the same period in 2024—just over double the number. The three age groups most affected are infants under one year of age (14%), children aged 1–4 (21%), and adults aged 30–39 (14%), who account for nearly half of all cases.

• Hospitalization was reported for 82 cases (45.6%) (including 6 in intensive care), and complications for 35 cases (19.5%) (including 20 cases of pneumonia and 1 case of encephalitis). Hospitalizations and complications primarily affected infants and young children, but also young adults.

• 70.5% of cases occurred in unvaccinated or incompletely vaccinated individuals.

• 34 departments in mainland France (33.6%) reported at least one case. No cases were reported in the overseas territories. More than half of the reported cases were concentrated in 5 departments: Nord (55 cases), Val d’Oise (15 cases), Bouches-du-Rhône (13 cases), Ain (9 cases), and Alpes-Maritimes (9 cases).

• During this period, 30 clusters of cases (groups of epidemiologically linked cases) were reported to the Regional Health Agencies (ARS) (provisional, unconsolidated data), resulting in a total of 113 cases. Among these, 7 clusters involved more than 5 cases and concerned individuals from the Roma community or of Romanian origin living in the general population, while the others occurred in group settings (daycare centers, high schools), in hospitals, or within families, with the exception of one cluster that occurred following attendance at a Parisian trade show.

• Of the 180 cases, 20% (36 cases) were imported cases (defined as a stay abroad during the 7 to 18 days preceding the onset of symptoms):

  • Countries of origin included Morocco (22 cases), Romania (3 cases), Italy (3 cases), Switzerland and Vietnam (3 cases each), and the Philippines and the United Kingdom (1 case each).

  • These imported cases triggered transmission chains within France, leading to 11 clusters involving 27 infected cases on French territory: 19 linked to cases imported from Morocco (primarily among close contacts of the cases or in healthcare settings), 7 linked to a case imported from Italy (daycare center), and one linked to a case imported from Vietnam (family).

  • The historic measles outbreak currently affecting Morocco since late 2023 has resulted in 41 cases in France since early 2025 (representing 23% of total cases): 22 cases following a recent stay in Morocco and 19 linked to an imported case from Morocco. Spain also reported numerous cases of measles imported from that country.

• The immediate reporting of cases to the Regional Health Agencies (ARS) and the submission of biological samples to the National Measles Reference Center (CNR) are essential for the early identification of clusters of cases and for implementing prevention and post-exposure prophylaxis measures around cases, particularly within communities.