This week, Elisabeth Borne called for masks to be put back on public transport, health authorities declared nationwide epidemics of flu and bronchiolitis, and on 9And The Covid wave is about to get carried away. Is it possible to be unlucky enough to be co-infected with all three viruses? We asked Eric Leroy, director of research at the Research Institute for Development (IRD), member of the National Academy of Medicine and the French Veterinary Academy.
“Co-infections are by no means uncommon”
Can you have all three diseases at the same time? WHO had already responded in part September 30, 2021 : Yes, it is possible to have the flu and Covid at the same time. And dozens of cases of “flurone” (short for “flu” and coronavirus) have been identified since 2020. Last November, theThe National Academy of Medicine has been alerted for its part on the “risk of excess mortality linked to viral co-infections”.
Because “co-infections are by no means rare,” explains Eric Leroy. “There are as many as fifteen viruses responsible for respiratory symptoms (flu, cold, bronchiolitis, etc.) that co-circulate stably and have been since the dawn of time. Some are more pathogenic or more media-friendly than others. You can be infected with one, two or three viruses. It’s classic medically and scientifically.”
So classic. However, it is difficult to give an estimate of the number of co-infected, because for this it would be necessary to test each patient for different viruses. A study in 2021 of the Bichat-Claude Bernard hospital (Paris) indicates that 6% of its tested Covid patients had also contracted another virus. “Co-infections with respiratory viruses are quite common,” Eric Leroy abounds. “I had done a study in Africa for a year. We had found about 10% co-infections. But we were looking for about fifteen viruses. For this Paris study, they looked for just two viruses. This explains a lower coinfection rate.”
It’s also unclear whether the viruses explode at the same time. Covid and the flu “are both respiratory diseases”, recalls the WHO. “The two viruses have symptoms in common, including cough, runny nose, sore throat, fever, headache and fatigue.” Furthermore, these viruses are spread in a similar way, “through droplets and aerosols emitted by an infected person when they cough, sneeze, speak, sing or breathe”.
Too many respiratory viruses to test
“There are co-infections that induce a reduction in symptoms for one or the other virus, others that enhance them”, deciphers Eric Leroy. “We don’t have many perspectives on this, because it depends on many parameters. In particular the methods of coinfection”.
The methods of coinfection are in fact the moment in which the virus is contracted. “When we’re infected, we keep the virus for a few days or even a week or two,” continues Eric Leroy. “We can therefore have a simultaneous coinfection – the two diseases at the same time – or successive – we are infected with a virus, and a few days later, while we are sick, we are infected with this other virus. Inevitably, these methods of infection will have an influence on symptoms. »
Exactly, can symptoms be a good indication of a co-infection? “I saw everything! This can range from no symptoms to severe symptoms,” says Eric Leroy. “It could be a combination of the two viruses, or the symptoms of one and not the other. The combinations are many.
The only way to know would be to test patients. Which seems unimaginable. “We will not have fun diagnosing all respiratory viruses: there are many! “Remember the member of the National Academy of Medicine.
The mask, “it’s common sense”
If symptoms are variable or even absent, when should we be concerned? Above all, you have to trust your instincts. “Everyone has their own feelings and a good perspective on how we react to all these viruses,” reassures Eric Leroy. “Everyone defines the threshold at which you have to see a doctor or go to the hospital emergency room.”
Between the epidemiological announcements and Prime Minister Elisabeth Borne’s call to wear a mask, the French may have a feeling of panic. “If we remove the context and the nature of the person saying it, the message is completely rational and logical,” reassures Eric Leroy. “We are in a seasonal epidemic context. This is what doctors tell their frail patients and those around them. It’s common sense. But said by a politician it takes on different proportions and connotations.
In any case, people most at risk, namely the elderly, people with chronic diseases and people with immunodeficiency, need to be especially careful. But not just this winter.
