what we know about the first case of the new variant detected in France

After Sweden, Germany, the United Kingdom and Belgium, it is France's turn. A first case of the new variant of the mpox virus, clade 1b, has been identified on the national territory, health authorities announced on Monday January 6. France becomes the fifth country in Europe affected by the appearance of this strain. Franceinfo takes stock of what we know about this contamination and, more broadly, this new variant.

A first case identified in Brittany

The Ministry of Health announced on Monday that it had been informed “a first human case of clade 1b mpox on the national territory, in Brittany”confirming daily information West France.

“The reported case concerns a person who has not traveled to Central Africa, an area in which the different clades of mpox viruses have been actively circulating for several months, including clade 1b”specifies the ministry press release. “This person, however, was in contact with two people returning from central Africa, investigations are underway to find the origin of the contamination and identify all the contact persons,” add the authorities.

Two clades of mpox are currently prevalent in the world

For the mpox virus (a(formerly called “monkeypox” or “monkey pox”), we distinguish two types of variants: clade 1 (and its subclades 1a and 1b) and clade 2 (and its subclades 2a and 2b), explains the World Health Organization (WHO).

Since 2022, an epidemic caused by subclade 2b has been raging worldwide. In France, 215 cases of mpox, all due to clade 2b, were declared to Public Health France (SPF) in 2024, with an average of three cases declared per week at the end of the year. Simultaneously, an increasing number of epidemic outbreaks due to subclades 1a and 1b are affecting the Democratic Republic of Congo and other African countries, but also other continents since this summer.

“The possible Differences in transmissibility, virulence and risk factors between the two subclades are still poorly known”, However, explained the national public health agency in a document intended for health professionals and dated August.

The fifth European country concerned

The variant called clade 1b has been detected for the first time in the Democratic Republic of Congo (DRC) in September 2023, explains the Ministry of Health. Cases have been recorded in various areas of the continent. According to the Africa Centers for Disease Surveillance and Preventionchildren under 15 are the most affected by this variant in Africa and represent at least 60% of cases. A finding that particularly worries Unicef.

The variant has gradually spread outside Africa, reaching Asian countries such as Thailand, but also Europe. The Ministry of Health recalls that four countries in the Old Continent have identified cases of clade 1b since this summer: Sweden, Germany, the United Kingdom and Belgium.

In August, the WHO has therefore decided to trigger its highest level of alert due to the increase in cases and the number of countries concerned.

Health authorities want to be reassuring

“The few cases that there have been in Europe call for vigilance, but for the moment [il n’y a] no reason to be worried about a large-scale outbreak“, infectious disease specialist Karine Lacombe explained on Monday on franceinfo, head of the infectious diseases department at Saint-Antoine hospital. “IWe must take the necessary precautions, but from there to being a generalized epidemic, we are still far from the situation”she assured.

The risk of mpox clade 1 infection for the general population in France and Europe is also considered low by the European Center for Disease Prevention and Control (ECDC, the EU public health agency) , underlines the Ministry of Health. “The recommended management measures have been put in place”argue the authorities. “But sporadic cases, linked to countries with more intense viral circulation, can occur. The occurrence of this case in France was quickly detected thanks to the surveillance system in place,” continues the ministry.

Vaccination remains recommended for people at risk

Health authorities recall the importance of vaccination for high-risk populations: men having homosexual relationships with multiple partners, transgender people with multiple partners, sex workers, professionals in places of sexual consumption, partners or people sharing the same living space as those at high risk of exposure.

People with close ties to Central African countries can also be vaccinated, the authorities further specify. In a press release published in November, the WHO also recalled that the vaccine is effective against the two clades in circulation.

— Ministry of Health and Access to Care (@Sante_Gouv) https://twitter.com/Sante_Gouv/status/1876551983156609390?ref_src=twsrc%5Etfw