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

Figures that worry. Since early 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 urging states to “control the outbreak of the virus,” World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus on Tuesday deemed the spread of the epidemic “unusual and worrisome.” “The situation requires a coordinated response.”

While initially only a few isolated contaminations were reported in the UK or Portugal, the number of identified cases and affected countries quickly exploded and now “the risk of monkeypox establishing itself in non-endemic countries is real,” according to the WHO , next A meeting of its emergency committee will be convened later this week to assess whether the virus constitutes a “public health emergency of international concern”. So, like Covid-19, can monkeypox become a pandemic?

A virus found on multiple continents

Discovered in Wuhan at the end of 2019, the Covid-19 very quickly crossed the borders of China and spread around the world within a few weeks. The first French case was identified in February 2020 and the following month WHO qualified Covid-19 as a pandemic.

Regarding monkeypox, the first non-endemic cases were identified in the UK on May 6th. In the following days, further contaminations are registered in several European countries and in the United States. In France, the first case was identified on May 19. And today there are more than a hundred. According to the latest figures shared by Public Health France on Tuesday, “125 confirmed cases have been reported in France, including 91 in Ile-de-France”. For the WHO, the “sudden and unexpected emergence” of the virus in non-endemic countries suggests that it has been circulating for some time without its transmission being proven. “As for Covid-19,” notes Dr. Benjamin Davido, specialist in infectious diseases at the Raymond Poincaré Hospital in Garches (Hauts-de-Seine).

Does this mean the planet is experiencing a monkeypox pandemic? ” You should be careful. But in fact we are facing a pandemic: the virus is present on several continents, and Europe is affected in a very unusual way, the infectiologist notes. If we are geographically on the spread of a pandemic, be 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 runaway disease.

Transmission routes and specific symptoms

Contamination from surfaces or from droplets: “We did a bit of fumbling before claiming that Covid-19 was mainly transmitted through aerosols,” recalls Dr. Davido. With monkeypox, we also tried to define the routes of transmission and the percentages that they represent.” Like Covid-19, monkeypox is a zoonosis, a disease originally transmitted by infected animals, wild or captive, dead or alive, such as rodents or monkeys transmitted to humans.

The two viruses differ in terms of symptoms. “Where Covid-19 has raised concerns about the risk of severe forms and lung damage, monkeypox is not associated with cases of pulmonary or neurological complications and is characterized by the appearance of skin lesions,” describes the infectiologist. While many publications show monkeypox in black men with hand lesions, the approximately 1,000 cases registered in recent weeks mostly affect Western men who have sex with men (MSM) with genital lesions. , emphasizes Dr. Davido, at the end of May, took care of two affected French patients. An “anogenital rash” present in “77% of the cases studied” points to Public Health France.

The specificity of these non-endemic cases stems from “their unprecedented route of sexual transmission through direct contact with the skin lesions or mucous membranes of a sick person. And all cases have lesions located exclusively at the genital level, Dr. Davido continued, author of an article on the subject published this Tuesday in the Journal of Travel Medicine. We are therefore on a very different transmission route than Covid-19, with a much slower rate of spread. And if the disease, like Covid-19 (since the massive vaccination campaigns), has a relatively low mortality rate of less than 1%, it remains very distressing for the sick. One of my patients said to me, “I’m afraid of losing my penis”.

Vaccines available but…

Fortunately, a human smallpox vaccine provides cross-immunity to monkeypox “with a high efficiency” of about 85%, affirmed Sylvie Briand, director of the Division of Pandemic and Epidemic Diseases at WHO. At the beginning of 2020, while we are talking about the “new coronavirus”, there is still no vaccine. It will be necessary to wait until the end of the year for the first anti-Covid vaccines to emerge – in record time – and start being administered.

But if labs have been able to produce millions of doses to protect against the coronavirus to date, the WHO doesn’t know how many doses of the smallpox vaccine are available worldwide. The organization is trying to take stock and is contacting “manufacturers (of vaccines) to find out their production capacities” and distribution, Sylvie Briand said. And “we may not have enough vaccines,” fears Dr. Davido. We do not know the state of the stocks that fall under the strategic reserve to deal with a bioterrorist threat.” But this Tuesday, the European Commission and the Danish laboratory Bavarian Nordic announced the signing of a contract for the purchase of more than 100,000 doses known.

Unlike Covid-19, the WHO “recommends no mass vaccination against monkeypox,” said Dr. tedros In France, the High Health Authority (HAS) recommends “contact case vaccination” or ring vaccination. A strategy “adopted during the human smallpox epidemic in Kosovo in 1972 and which made it possible to put an end to it in a few weeks,” recalls Dr. Davido.

Reflexes to be adopted to break the chains of transmission

Individually, as with Covid-19, reflexes should be adopted to break the chains of transmission of monkeypox. “We know that the disease can be very contagious, just like chickenpox and human smallpox, by causing infectious scabs,” explains Dr. Davido. From the moment you have an outbreak of illness or lesions on your body, call 15 to get tested immediately and start tracking contact cases to get vaccinated. Then the patients have to isolate themselves until the scabs have completely disappeared, that is about three weeks”.

And in cases that are characterized by sexual transmission, “it is important to practice prevention, as we do with other sexually transmitted infections (STIs),” emphasizes the infectiologist. Then, as cases explode and stocks allow, it may be appropriate to recommend vaccination of vulnerable populations.” For the time being, “we have all the elements to avoid the pandemic: we know the virus, it’s less transmissible and we have a vaccine,” summarizes Dr. David together.

But without a strategy of increased surveillance and swift action on each identified case, the scenario could lead to massive contagion, predicts a team of Dutch, Swiss, German and American researchers conducting a study published in February in the journal Plos Neglected Tropical Deseases definitely have cases of monkeypox that have been recorded since the emergence of this virus and who are guessing it could be the next big pandemic. Why ? “The decline in population immunity associated with the cessation of smallpox vaccination has created the landscape for a resurgence in monkeypox,” the researchers point out. This is reflected in the increase in the number of cases and the average age of those affected. In addition, the emergence of cases outside of Africa underscores the risk of the disease spreading geographically, they warn. Given the current pandemic threat, the importance of monkeypox to public health cannot be underestimated.”

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