In the context of a persistent circulation of the SARS-CoV-2 and of the circulation of winter viruses, the HCSP recommends the following measures.

In the general population:

• promotion of influenza vaccination among those people eligible in the 2020 vaccination calendar, in particular among healthcare workers;
• strict compliance with protective measures during the winter period;
• PCR testing of upper airways samples, in case of any Covid-19 symptoms or high-risk contact with an infected person;
• a diagnostic test for influenza in accordance with usual practice (community at risk, serious respiratory infection requiring hospitalisation, etc.), giving preference to molecular tests, especially in adults;
• simultaneous testing for the influenza virus and the SARS-CoV-2, especially for at-risk populations and during co-circulation periods.

For communities of elderly people:

• reinforce the recommendations for influenza vaccination among residents and nursing staff in accordance with the recommendations of the vaccination calendar;
• strengthen clinical surveillance to look for symptoms of acute respiratory infection;
• use molecular tests to screen for SARS-CoV-2 and influenza viruses in parallel.

In children under 6, the guidelines for management and surveillance (looking for signs of severity) of epidemic viral diseases remain valid. The HCSP specifies the situations where SARS-CoV-2 testing is either not recommended, recommended to be performed rapidly or should be performed secondarily in regard with the evolution.

Beyond the age of 6, due to the lower frequency of seasonal viral infections than in very young children, Covid-19 testing can be performed as in adults, outside of highly suggestive epidemic contexts.

With regard to multiplex testing, according to the above recommendations, a rapid antigenic test or a molecular test able to detect respiratory syncytial virus (RSV), influenza viruses or rotavirus is recommended to establish the diagnosis in case of symptoms compatible with these pathologies. In cases for which a co-infection with SARS-CoV-2 is suspected, this agent must also be tested, by using preferentially a multiplex test dedicated to respiratory pathogens if this kind of test is available at affordable cost.