Covid-19: Should we be worried about the rise in cases this fall?

Covid-19 ? It never went away! The bad news is that this summer, the virus spread again, affecting all ages and all regions - with a concentration of cases in Île-de-France and Hauts-de-France.

In city laboratories, the latest national bulletin from the Pasteur Institute reports a "steady increase" in positive tests, with 18.66% of positive detections during the last week of August 2025.

In its latest weekly bulletin, published this Wednesday, September 3, 2025, Public Health France notes an increase in emergency room visits in France for suspected Covid-19 infections. This is around +20% among those under 15, and +12% among those aged 15-74, during the week of August 25 to 31.

However, virologists reassure that the "additional risks" linked to increased circulation of the virus are particularly limited.

"The current situation is not at all comparable to what we observed at the beginning of the pandemic, and that's no surprise. There is therefore nothing to fear," explains Antonin Bal, deputy director of the National Reference Center for Respiratory Infections (CNR) in Lyon.

Are the additional cases due to the variants? While last May it was the NB.1.8.1 variant that caught the attention of specialists in France, it is ultimately the XFG (belonging to the Omicron family) which, at the beginning of September, is the most represented in the observed positivity rates.

"It should be noted, however, that the progression of the XFG variant was probably more significant in August than in July," specifies Antonin Bal.

So far, symptoms of the new XFG variant are relatively similar to those previously observed for other variants: runny nose, headache, sometimes muscle pain with stiffness and, more rarely, loss of taste or smell.

"If the patient's respiratory condition worsens, you must be vigilant and seek medical advice. Hospitalization may be required if the distress is significant," concludes Antonin Bal.

Another finding from the CNR: it appears that Covid-19 circulates more frequently in the spring and summer. This is something that has already emerged from previous scientific findings and now appears to be confirmed.

"Even though the virus's progression came later this year than in 2024 , the positivity rates are once again higher at this time," adds the virologist. However, no seasonality has, for the time being, been officially established by the medical profession.

Although the risk of developing a serious or severe form of Covid-19 remains limited, the CNR nevertheless emphasizes the importance of vaccination monitoring for the most vulnerable people (elderly, immunocompromised, HIV-positive, etc.). The next vaccination campaign has not yet been announced by the health authorities.