06:00, August 16, 2022
The Covid-19 pandemic having made us Sunday epidemiologists, but without giving us the certainty of correctly interpreting the incidence curves, we submitted this burning question to our address book: “Is the progression of monkeypox exponential? » In other words, should we, in the heart of summer, raise the level of concern in the face of a still unknown virus? Well, according to the specialists, the answer is not simple.
A few undisputed figures to set the equation: more than 27,800 cases have been reported since the beginning of the year, with an acceleration since the arrival of the disease in Europe and North America in May, according to the WHO; 2,673 confirmed contaminations had been identified in France on Thursday. So what do the experts say? “It is not exponential for the moment”, sweeps away one of the pilots of crisis management, even if Public Health France has been responsible for settling this mathematical controversy.
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The epidemiologist Antoine Flahault, director of the Institute of global health in Geneva, detects him, the index of a worrying flight: “The number of cases is doubling globally every fortnight or so and the growth has not slowed in the past month. It’s an exponential: we can go to infinity very slowly. » A former Minister of Health also urges vigilance: “People don’t understand what an exponential is. Even if the number of cases remains low, there will be a moment of acceleration. We can’t stop the progression of the virus, so here we go. »
How far ? Difficult to know as the projections remain hazardous. Antoine Flahault estimates that at this rate 80,000 cases could be exceeded worldwide by the end of August. “We are unable to circumscribe outbreaks that are nevertheless restricted, he observes. We may be witnessing the start of a pandemic. » More cautious, the infectiologist and director of the National Agency for Research on Infectious Diseases Yazdan Yazdanpanah also assures that “it is not a virus that should be allowed to circulate”.
The fear of contamination in children
First pitfall: the difficulty in tracing the chains of contamination. Because monkeypox, which mainly seems to be transmitted through close contact, is mainly spread among gay, bi or trans people with multiple, often anonymous partners. This mode of dissemination via backrooms and saunas, which defeats contact tracing, remains prevention. In order to protect oneself and, in the event of symptoms, to refrain from contaminating one’s lovers, always or one evening. “It really is the number one tool, explains Professor Yazdanpanah. To promote self-diagnosis, it is necessary to explain what the lesions, often located on the penis, anus or mouth, look like. »
Second pitfall: the vaccination campaign for groups at risk is not moving fast enough. At the current rate, all eligible persons “will be vaccinated only at the end of December, and with a single dose”, tackle Act Up Paris, Aides, Sidaction and Le Strass (sex work union). The situation would then be ” out of control “argue these associations fighting against discrimination against LGBT + and HIV-positive people. “The vaccine is the base, completes Fabrice Pilorgé (Aids). We have to step up the pace because there is a real risk that things will flare up at the end of the summer, during festive events in particular. » Very mobilized, these activists still hope, as evidenced by messages posted on a Telegram group devoted to monkeypox (English name of the disease), to see the virus confined to their communities. “The health emergency is that it does not affect the rest of the population”, thus sums up Fabrice Pilorgé.
Read also – Monkey pox: “We still have a lot of uncertainty about the future dynamics of this epidemic”
An epidemic that would change its face in the fall with mass contamination among children, as in the African cradle of the virus, such is also the fear of the government. “We fear that it will slip into the general population”, indicates a high-ranking source. Also the study of a recent family cluster around a heterosexual couple in a campsite in Fréjus (Var) has focused all the attention. “Contact tracing has almost been abandoned among men, says another interlocutor. But we continue when it comes to women or atypical cases. »
Mutations of “unknown significance”
While waiting to find out if the gay community, and more broadly that of men who have sex with other men, will have been the gateway to the virus or a providential impasse, the experts are reassured on the grounds that this disease, cousin of fire the terrible smallpox, does not seem ” very severe “. But epidemiologist Antoine Flahault warns: “Monkeypox is not benign. 10% of patients have complications, 5% are hospitalized*. The burden is heavy. »
The last unknown relates to the pathogen itself. “If the future is so uncertain, it is in particular because we do not yet know whether this virus, endemic to Africa, has evolved, specifies Anne-Claude Crémieux, professor of infectiology. Whether the outbreak is mainly due to human factors (festive gatherings) or immune factors (stopping smallpox vaccination in 1980 which offered cross-protection against monkeypox), it is controllable. But if the virus has mutated to better adapt to humans by becoming more transmissible, it is much more worrying. » In the words of the British authorities, the mutations recently detected by the researchers have “an unknown meaning”. All we know is that we know almost nothing. Like two and a half years ago, when Sars-CoV-2 appeared.
* And not 40% and 20%, as indicated above. Indeed, only half of hospitalized patients are there for serious forms, the others are for isolation.