Primary Outcome Measures:
- The number of household contacts who will develop within 7 days of the inclusion of the index patient a respiratory syndrome defined by fever> = 37.8 ° C and a cough or a sore throat. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
Secondary Outcome Measures:
- clinical events in all household members on the entire monitoring period (21 days). [ Time Frame: 21 days ] [ Designated as safety issue: Yes ]
- Adverse events related to wearing a mask - a safety issue. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Number of days of wearing a mask, number of masks used. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Drug-consumption, in particular antibiotics [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Sick-leave from work (for adults contacts), or from school (for children of school age). [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Quality of life in the index patient. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Infection with influenza virus at different time, among all household members. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Quantification of viral load in patients infected. [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
- Characterization of viruses isolated (sub-type and sequence of the portion of HA1 gene for haemagglutinin). [ Time Frame: during the study ] [ Designated as safety issue: Yes ]
Background. Non pharmaceutical interventions, and in particular the wearing of face masks, could play a role in controlling the transmission of influenza in the early stages of the epidemic. In the French pandemic plan, surgical masks are recommended in contagious patients in wards. The effectiveness of such masks in preventing transmission of influenza A virus is unknown. Our project aims to assess the preventive efficacy and tolerance of surgical mask.
The primary objective is to measure the decrease of the number of secondary cases of flu in households where the index case will wear a surgical mask during its period of infectiousness (5 days), compared to households where the index case will not be subject to this intervention. Secondary objectives are: (1) to study the feasibility and tolerance of wearing a mask continuously during the period of viral shedding; (2) virological description of infection spreading among household contacts based on virological collections.