Transmission, number of cases… After Covid-19, will monkeypox be the next major pandemic?

Worrying numbers. Since the beginning of May, more than 1,600 confirmed cases of monkeypox have been reported in 32 countries where the disease is not endemic. Less than a week after Tedros Adhanom Ghebreyesus, director general of the World Health Organization, called on states to “control the outbreak” of the virus, Tedros Adhanom Ghebreyesus on Tuesday called the outbreak “unusual” and worrying “, saying that” the situation requires a coordinated response “.

While initially only a few isolated contaminants were reported in the UK or Portugal, the number of cases identified and countries affected has rapidly exploded and now, “the risk that monkeypox is spreading to non-endemic countries is real, ”said WHO, which will convene a meeting of its emergency committee next week to assess whether the virus is an“ international public health emergency ”. So, like Covid-19, can the monkeypox contagion turn into a pandemic?

A virus present on several continents

Launched in Wuhan at the end of 2019, the Covid-19 is rapidly crossing China’s borders and spreading around the globe in a few weeks. The first French case was identified in February 2020 and then the WHO described Covid-19 as a pandemic.

With regard to smallpox, the first non-endemic cases have been identified since 6 May in the United Kingdom. In recent days, other contaminants have been reported in several European countries and the United States. In the Hexagon, the first case is identified on May 19. And today there are more than a hundred. According to the latest figures released on Tuesday by Santé publique France, “125 confirmed cases have been reported in France, including 91 in Ile-de-France.” According to the WHO, the “sudden and unexpected onset” of the virus in non-endemic countries suggests that it has been circulating for some time, but has not been detected. “Come for the Covid-19,” says Dr. Benjamin Davido, an infectiologist at Raymond-Poincaré de Garches Hospital (Hauts-de-Seine).

Does this mean that the planet is experiencing a monkeypox pandemic? “It simply came to our notice then. But in fact, we are facing a pandemic: the virus is present on several continents, and in a very unusual way, Europe is affected, notes the infectiologist. If, from a geographical point of view, we are on a pandemic distribution, this is not yet the case on the numbers side, he reassures. There is an increase in contamination, but we are not (yet) facing a rampant disease ”.

Specific modes of transmission and symptoms

Contamination by surfaces or droplets: “There was little trial and error before claiming that Covid-19 was transmitted primarily by aerosol,” recalls Dr. Davido. With the smallpox of the monkey, we also tried to define the modes of transmission and the percentages they represent. Like Covid-19, monkeypox is a zoonosis, an initialization of the disease transmitted to humans through infected animals, wild or captive, dead or alive, such as rodents or les singes.

On the symptom side, the two viruses differed. “Where Covid-19 has caused concern with the risk of severe form and lung damage, monkeypox is not associated with any pulmonary or neurological complications, and is characterized by the appearance of skin lesions, described by the infectiologist. However, while many publications illustrate monkeypox with black people with hand injuries, the 1,000 or so cases in recent weeks have mainly affected men who have sex with Western men (MSM) with genital injuries. ” , underlines Dr. Davido who, at the end of May, took care of two affected French patients. An “anogenital eruption” is present in “77% of cases under investigation,” according to Santé publique France.

The peculiarity of these non-endemic cases is based on “their unprecedented mode of sexual transmission, through direct contact with skin lesions or mucous membranes of a sick person.” And all the present cases of exclusive lesions located at the genital level, to complete Dr. Davido, the author of an article à paraître in Journal of Travel Medicine. On a transmission mode very different from Covid-19, with a much slower propagation speed. And if, like Covid-19 (since mass vaccination campaigns), the disease has a relatively low lethality rate of less than 1%, it remains very distressing for patients. One of my patients told me, “I’m afraid of losing my penis.”

Often vaccines available, more …

Fortunately, a human smallpox vaccine offers about 85% cross-immunity to monkeypox “with a high level of efficacy,” said Sylvie Briand, director of the WHO’s Department of Pandemic and Epidemic Diseases. In early 2020, when it comes to the “new coronavirus”, no vaccine exists yet. He will have to attend at the end of the year to receive the vaccines against Covid no voient le jour – in record time – and begin to be administered.

Several laboratories have been able to produce millions of doses to protect against coronavirus. Today, the WHO has not said how many doses of smallpox vaccine are available worldwide. The organization seeks to inventory stocks and contact “(vaccine) manufacturers to find out their production and distribution capabilities,” said Sylvie Briand. And “we may not have enough vaccines,” says Dr. Davido. The state of the stocks, which are part of the strategic reserve to deal with a bioterrorist threat, is unknown ”. But on Tuesday, the European Commission and the Danish laboratory Bavarian Nordic announced the conclusion of a contract for the purchase of more than 100,000 doses.

Unlike Covid-19, the WHO “does not recommend mass vaccination against smallpox,” said Dr. Tedros. In France, the Haute Autorité de santé (HAS) advocates “contact vaccination” or ring vaccination. A strategy adopted “in 1972 during the human smallpox epidemic in Kosovo, which put an end to it in a few weeks,” recalls Dr. Davido.

Reflexes to be adopted to break the transmission chains

Individually, for Covid-19, the reflexes are adoptive for the casser les chaînes of monkeypox transmission. “We know that the disease can be very contagious, such as chickenpox and smallpox in humans by causing infected crusts,” said Dr. Davido. So from the moment you have an eruptive disease, lesions on the body, you call the 15th to be screened without delay and start tracing the contact cases to vaccinate them. Then the patients have to isolate themselves until the crusts are completely gone, which is about three weeks. ”

And with cases that are characterized by sexual transmission, “it’s important to do prevention, as you do with other sexually transmitted infections (STIs),” insists the infectiologist. Then, if the cases explode and the stocks allow it, maybe it will be opportune to recommend the vaccination of the populations at risk ”. For now, “we have everything to prevent the pandemic: we know the virus, it is less transmissible, and we have a vaccine,” says Dr. Davido.

Moreover, without a strengthened surveillance strategy and rapid action around each identified case, the scenario could turn into a massive contagion, predicting a team of Dutch, Swiss, German and American researchers who maintained a study published in February in the journal . Plos Neglected Tropical Deeases on all cases of smallpox in the blood reviewed since the onset of this virus and which it estimates could be the next major pandemic. Why? “The decline in immunity of the population associated with the cessation of smallpox vaccination has established the landscape of the resurgence of monkeypox,” the researchers point out. This is demonstrated by the increase in the number of cases and the median age of those who contract it. In addition, the occurrence of cases outside Africa highlights the risk of geographical spread of the disease, they warn. In light of the current pandemic threat environment, the public health importance of monkeypox should not be underestimated. ”

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