Runny nose, dry cough, fever: this classic picture of Covid no longer corresponds to what doctors have been observing since the start of the 2026 school year. The virus is circulating again in France, but its manifestations have shifted towards unusual signs, often confused with gastroenteritis, fatigue, or a simple allergy. Recognizing these atypical symptoms allows for quick action, testing, and protecting those around you.
Why the XFG variant is confusing the picture in September 2026
Since the start of the school year, it is the XFG variant, nicknamed “Frankenstein” because it is derived from the fusion of two Omicron lineages, that dominates the circulation of SARS-CoV-2 in France and around the world. This recombinant has the particularity of causing digestive and neurological symptoms rather than respiratory ones.
Specifically, a patient infected with XFG may suffer from nausea, diarrhea, or abdominal pain for several days without ever coughing or developing a fever. They consult for what they believe to be seasonal gastroenteritis. The general practitioner may not always think of Covid in the face of such a presentation.
This disconnect between the mental image of Covid (cough, fever, loss of smell) and the current clinical reality delays diagnosis. An article detailing Covid in September 2026 on Compar Santé precisely describes this evolution of the symptomatic profile.
Digestive disorders, confusion, and skin rashes: the new face of Covid
Have you ever had gastro that lingers for more than a week without a clear explanation? This is exactly the type of situation that should raise alarms right now. The atypical symptoms reported since September fall into three distinct categories.
Persistent digestive signs
Vomiting, diarrhea, abdominal cramps: these manifestations affect both adults and children. The Oscour bulletin from Public Health France on September 30, 2026, notes an increase in emergency visits for gastroenteritis and acute abdominal pain among those under 15 years old.
The duration often distinguishes Covid from a common gastro. A classic viral gastroenteritis lasts two to three days. If the symptoms persist beyond that, a Covid self-test deserves to be taken out of the cupboard.
Mental fog and general malaise
The second category of signs: disproportionate fatigue associated with temporary confusion. Patients describe difficulties concentrating, unusual forgetfulness, or a sensation of “head in the clouds” that lasts several days.
Among those under 15, Public Health France has observed an increase in the “general malaise” reason for emergency visits, alongside suspicions of Covid. This symptom, which is not very spectacular, easily goes under the radar because it does not fit the expected respiratory pattern.
Skin rashes and conjunctivitis
The third, less known signal: increased skin rashes and cases of conjunctivitis. Visits for conjunctivitis rose at the end of September 2026 among those under 15 and adults aged 15 to 74, according to Oscour data. The direct causal relationship with SARS-CoV-2 is not formally established for each individual case, but the temporal coincidence with the resurgence of the epidemic constitutes a clinical signal to monitor.
Unusual joint pain sometimes complements the picture, reinforcing the confusion with other autumnal pathologies.
Covid or back-to-school pathology: how to tell the difference
September annually concentrates a peak of respiratory viruses, gastroenteritis, and ENT pathologies related to the return to group settings. Distinguishing Covid from a simple cold or sore throat is not always straightforward, especially when cough and fever are absent.
Here are the elements that guide towards a Covid test rather than a trivial infection:
- Digestive symptoms lasting more than three days without clear improvement, especially if accompanied by muscle aches or intense fatigue
- A mental fog or sudden difficulty concentrating, without an obvious context of overwork or lack of sleep
- Bilateral conjunctivitis (both eyes affected) associated with at least one other symptom (fatigue, muscle pain, digestive disorders)
- A loss or alteration of smell, even mild, which remains a relatively specific marker of SARS-CoV-2
The dynamics of the resurgence are also measurable in wastewater, confirming that the virus is actively circulating this school year.
Children and atypical symptoms: an even more misleading picture
In children, the XFG variant manifests in particularly confusing ways. Data from Public Health France show a simultaneous increase in emergency visits for vomiting, ENT pathologies, and general malaise among those under 15 at the beginning of September 2026.
A child who vomits and complains of stomach pain is common during the back-to-school period. What should raise alarms is the association of several signs: digestive disorders, marked fatigue, and possibly red eyes. This combination justifies a self-test before sending the child back to school.
ENT pathologies (rhinitis, otitis) have also significantly increased in early September. They can coexist with a Covid infection without the link being immediately identified by the treating physician.
Self-test and consultation: when to react concretely
In the face of unusual symptoms that persist, the self-test remains the first useful reflex. In case of a negative test but ongoing symptoms, a medical consultation allows for an evaluation of the situation and, if necessary, the prescription of a more sensitive PCR test.
Barrier gestures remain highly relevant, particularly regular hand washing and wearing a mask in case of symptoms, even if they resemble gastro more than a cold.
Covid in September 2026 no longer resembles what most people have in mind. Abdominal pain, fuzzy head, irritated eyes: these signs warrant a self-test, especially when they linger beyond a few days.
