Following the report on the 4th of September 2020 of two confirmed indigenous cases of dengue fever in Nice and another case in La Croix-Valmer in the Var department, the High Council for Public Health (HCSP) was seized on 7 September 2020 by the General Directorate for Health (DGS). Five new cases occurred after this date, three in Nice (same outbreak), one in La Croix-Valmer (same outbreak) and one in Gard near Alès (new outbreak). Two new cases were reported even later in Saint Laurent-du-Var (new outbreak).

Following a first provisional opinion on the 21st of September 2020 to establish as quickly as possible recommendations on the criteria for deferral or exclusion to be implemented for both labile blood products and grafts from donors who have been in risk areas, the present HCSP opinion comments on all the data collected from the epidemiological and virological angles, as well as the actions taken; it formulates additional recommendations.

In response to a request from the DGS on the definition of criteria that would make it possible to trigger an intervention without waiting for confirmation from the CNR and without requiring an emergency meeting of the HCSP (Secproch alert working group), the present opinion includes in annex a technical sheet that summarises the management and information measures recommended for the Regional Health Agency and its partners, the French Blood Establishment, the Armed Forces Blood Transfusion Centre and the Biomedicine Agency, in simple cases where the epidemic outbreak(s) does (do) not exceed 3 cases of autochthonous dengue hosted in the same household on the metropolitan territory. Other situations will continue to be submitted to the HCSP working group for advice.