Monkey pox: a first case of the new variant identified in France

It was expected, it’s now official. A first patient infected with the new variant of the monkeypox virus (mpox, formerly monkeypox) has been identified in France, the Ministry of Health announced this Monday evening. This is a woman hospitalized at Rennes University Hospital but whose condition does not cause concern, according to Ouest-France.

This new strain, clade Ib, was first identified in the Democratic Republic of Congo (DRC) in late 2023. It then spread to other African countries and eventually reached the rest of the world, starting in last summer. Sweden, first, with a first confirmed case on August 15. Then Thailand, a few days later, and Germany, on October 22. In the United Kingdom, a first patient was detected on October 30, then two others, living in the same household, a week later. Finally, a first case was recorded in Belgium in December.

Another variant is already circulating in France

Since mid-August, doctors and laboratories in France have been called upon to be extremely vigilant in the face of any suspicion. Like many of her colleagues, infectious disease specialist Karine Lacombe expected that a case of clade 1b would eventually be detected. “We have already alerted all our outpatient structures,” the head of the infectious diseases department at Saint-Antoine hospital (AP-HP) told us in mid-August. The goal is to encourage these patients to isolate themselves, in order to prevent any transmission.

The mortality rate of clade I (which brings together Ia and Ib) has been estimated at nearly 4% in the general population, but in an African country (the DRC) where the health system is less solid than in Europe and where the Access to treatments is less simple. In other words, this value is not applicable to Europe and therefore to France. And this, especially since the mortality rate could be overestimated by poor screening. Many people infected in Africa are not detected, and therefore not taken into account in the calculation.

This new virus seems to be transmitted more easily than its “cousin” from clade IIb, which had already circulated in France and in many Western countries in 2022 and 2023, mainly affecting homosexual men (more than 5,000 confirmed cases in France). It can be spread through close contact (including sexual intercourse), through contaminated objects and perhaps also through respiratory droplets.

This clade IIb is still circulating in France, quietly, with more than 200 cases recorded this year. Faced with the threat represented by the new variant, the World Health Organization (WHO) decreed the highest level of international alert on August 14, to encourage the entire world to coordinate.

Vaccination still offered

In addition to prevention measures (screening, isolation, etc.), we have another weapon at our disposal: vaccination, always offered in France to people at risk (men who have sex with men, sex workers, etc.). .). Several Western countries have also promised to deliver hundreds of thousands of doses to the African continent.

The effectiveness of these smallpox vaccines has been established, in several studies, against strain IIb. Will it be equivalent to the new clade Ib? It is likely, “although the evidence is currently lacking,” responded the European public health agency in mid-August. On the other hand, the antiviral treatment Tecovirimat appears to have no effect on this new clade, according to a study carried out in Africa.