There are two categories of MSOs:

• 33 diseases that require both urgent local, national, or international intervention and special surveillance to protect public health, as defined in categories 1 and 2 of Article L 3113-1 of the Public Health Code,
• 5 diseases for which only surveillance is required under Category 2 of Article L 3113-1 of the Public Health Code. These include HIV infection at any stage, acute hepatitis B, tetanus, mesotheliomas, and COVID-19.

The inclusion or removal of a disease from the list of MSOs is decided by the Minister of Health via a decree issued after consultation with the High Council for Public Health (HCSP). Depending on the MSO group, this decree amends Article D3113-6 or Article D3113-7 of the HCSP.

An order issued by the Minister of Health specifies, for each MSO, the individual clinical, biological, and sociodemographic data to be transmitted to the health authority. This data is submitted via a Cerfa form, which is gradually being digitized through:

• the e-DO tool, which has enabled online reporting of HIV/AIDS infections since 2015 and tuberculosis since 2019;
• the reporting portal, which has provided access since April 22, 2026, to digital versions of the Cerfa forms for the following MSOs: measles, chikungunya, dengue, Zika, and West Nile virus;
• LaboéSI, which allows laboratory technicians exclusively to submit their COVID-19 data electronically.

For other notifiable diseases, Cerfa forms must be downloaded and submitted to the ARS by any available means (secure messaging, fax, or postal mail). 

List of Notifiable Diseases