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, as defined in 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 addition or removal of a disease from the MSO list is decided by the Minister of Health through a decree issued after consultation with the High Council for Public Health (HCSP). Depending on the MSO category, this decree amends either 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 submitted 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, as of April 22, 2026, provides access to digital versions of the Cerfa forms for the following MSOs: measles, chikungunya, dengue, Zika, and West Nile virus;
• LaboéSI, which allows laboratory technicians only to submit their COVID-19 data electronically.

For other communicable diseases, the Cerfa forms can be downloaded and submitted to the ARS.

Reporting entities (physicians and heads of clinical laboratories) must submit the reporting forms to the ARS using the secure procedures defined by that authority: be sure to consult the relevant page on the ARS website regarding mandatory reporting. In case of an emergency, you can also contact the ARS’s point of contact by phone at the number listed on its website.

List of Reportable Diseases