Winter Outbreaks - 2021–2022 Season
Every year, winter viruses cause outbreaks of the flu, gastroenteritis, and bronchiolitis. Starting in October, Santé publique France publishes a weekly update tracking the trend in the number of cases in France and reminds the public of the preventive measures they should take to reduce the risk of infection.
Winter viruses
thematic dossier
Every year, winter viruses cause outbreaks of the flu, gastroenteritis, and bronchiolitis. Simple preventive measures can reduce the risk of infection.
Every year, millions of people are affected by winter viruses: influenza, bronchiolitis, and gastroenteritis. The COVID-19 pandemic had a direct impact on the circulation of viruses during the 2020–2021 winter season and on the winter outbreaks typically observed each year; a decline in the number of cases, mainly due to the strengthening of preventive measures (mask-wearing, physical distancing, etc.) and measures to curb the COVID-19 epidemic, which also impacted the circulation of other viruses (lockdowns, travel restrictions, social distancing, etc.).
Winter surveillance for 2021-2022 resumed in early October with the publication of the first surveillance bulletins. The published data already show early circulation of the bronchiolitis virus and active circulation of the influenza virus in Mayotte.
What are the winter epidemics?
Influenza, gastroenteritis, and bronchiolitis are the main infections caused by winter viruses, and they place a heavy burden on healthcare systems during the winter.
Influenza
Influenza is a contagious respiratory viral infection that causes seasonal epidemics in the winter. In mainland France, the epidemic generally occurs between November and April, most often starting in late December or early January. It lasts an average of 10 to 11 weeks.
Between 2 and 6 million people are affected by the flu each year in France. There are various ways to protect yourself: the flu vaccine is the most effective method, but it is just as important to follow preventive measures.
Bronchiolitis
Bronchiolitis is an epidemic respiratory disease caused primarily by the respiratory syncytial virus (RSV). It mainly affects children under the age of 2. The epidemic typically begins in mid-October, peaks in December, and ends by the end of winter.
In France, it is estimated that bronchiolitis affects nearly 30% of infants under 2 years of age each winter, representing approximately 480,000 cases per year. Currently, prevention relies primarily on hygiene measures.
Gastroenteritis
Winter acute gastroenteritis (AGE) is primarily viral in origin, with noroviruses and rotaviruses being the most prevalent. Noroviruses cause AGE in people of all ages, while rotaviruses primarily affect children under 5 years of age. The number of AGE-related visits to healthcare providers typically increases between December and April. A peak is often observed during the first two weeks of January.
It is estimated that, each winter, these cases of AGE account for 1.4 to 4.0 million visits to primary care physicians. Since the transmission of acute viral gastroenteritis is primarily person-to-person, prevention measures are primarily based on the practice of hygiene, particularly hand hygiene.
Enhanced surveillance during the winter season
As part of its surveillance, monitoring, and alert missions regarding seasonal epidemics, Santé publique France analyzes surveillance data on influenza, bronchiolitis, and acute gastroenteritis from its network of partners.
The analysis of this data is published weekly between October and April in national and regional epidemiological bulletins.
Stay informed by subscribing to our weekly newsletters.
Simple precautions to take during the winter
To reduce the risk of catching a winter virus, Santé publique France recommends a few simple preventive measures:
Wear a disposable mask when in contact with the elderly, infants, people with chronic illnesses, or pregnant women, as soon as the first symptoms appear (fever, cough, sneezing).
Wash your hands regularly with soap and water (preferably liquid) for 30 seconds, scrubbing your nails, fingertips, palms, the backs of your hands, wrists, and between your fingers. After washing, it is recommended to dry your hands with a clean towel or let them air dry. According to the World Health Organization (WHO), this is the most important hygiene measure for preventing the spread of infections. It is strongly recommended to wash your hands as often as possible, especially at times considered essential:
before and after caring for a baby
after visiting a sick person
before preparing, serving, or eating meals
after blowing your nose, coughing, or sneezing
after every time you go outside
after using public transportation (bus, coach, train, subway), upon arriving at the office or at home
after using the restroom.
The use of hand sanitizers (SHA) is effective at eliminating many transmissible microbes, but it is not effective against all germs. They should be used on hands that are visibly clean, as they disinfect but do not remove dirt from the hands. Use a disposable tissue to blow your nose, throw it in the trash, and then wash your hands. At home, a trash can with a lid is preferable.
Sneeze or cough into the crook of your elbow. If you cover your mouth and nose with your hand, the germs on your hand can spread to others through handshakes or by touching objects. If this isn’t possible (e.g., holding a child), it’s recommended to cover your mouth with a disposable tissue, throw it away, and then wash your hands. After coughing or sneezing into your hands, wash your hands as soon as possible to avoid contaminating people or objects.
WATCH THE VIDEO OCTOBER 1, 2021
