Every year, there is an increase in cases of acute gastroenteritis (AGE), caused primarily by the circulation of noroviruses and rotaviruses. Noroviruses cause AGE in people of all ages, while rotaviruses mainly affect children under the age of 5.

During the winter season, Santé publique France, together with its network of partners, monitors the epidemiological trends of acute gastroenteritis and publishes weekly national and regional epidemiological bulletins on its website. This data is also made available as open data on Géodes.

Santé publique France is releasing today the summary of its winter surveillance covering the 2020–2021 and 2021–2022 seasons in metropolitan France and reminds the public of simple measures to take to limit the risk of infection.

What were the highlights of the past two seasons?

2020–2021: A season marked by historically low activity levels

The low level of activity observed starting in March 2020 (end of the 2019-2020 season), amid the COVID-19 pandemic, continued throughout the 2020-2021 season. In private practice and in hospital emergency departments, activity remained relatively stable and lower than in the years prior to the COVID-19 pandemic across all metropolitan areas.

A return to activity levels comparable to pre-COVID seasons during the winter of 2021–2022

Activity levels recorded throughout the 2021-2022 season were once again comparable to those observed during pre-COVID seasons. In hospital emergency departments, activity for acute gastroenteritis remained close to historical highs from December 2021 to April 2022. Consultations at SOS Médecins were similar to the data observed before the COVID-19 pandemic.

Children under 5: a group particularly affected in 2021

Among children under 5, acute gastroenteritis activity saw a particularly sharp increase starting in mid-November 2021, reaching levels comparable to the peaks observed during pre-COVID seasons at the same time of year. This significant resurgence of activity in this age group could be explained by the lack of acquired immunity against the most frequently isolated viruses (rotavirus and norovirus) in the two cohorts of children born in 2020 and 2021, thereby increasing the number of children susceptible to enteric viruses. Indeed, the containment measures taken to control the COVID-19 epidemic (enhanced hygiene measures, lockdowns, closure of preschools, etc.) may have limited the circulation of enteric viruses1.

Rotavirus vaccination for infants and young children

Rotavirus vaccination is now recommended by the HAS in France for all infants. Its purpose is to protect young children from diarrhea—sometimes severe—caused by these viruses, which may require hospitalization. To inform parents, Santé publique France has created a new informational brochure: 5 Good Reasons to Get Vaccinated. This brochure is available for download on our website and can be ordered by all healthcare professionals.

In addition, the website vaccination-info-service.fr answers questions that the general public and healthcare professionals may have about vaccination.

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