Effectiveness, stocks, targeted people… What you need to know about vaccination against mpox

A new variant of the virus, more contagious and more deadly, has arrived in Sweden, where one case has been reported, and is raging in Africa. Scientists are, however, confident about the effectiveness of the current vaccine.

Are we sufficiently equipped against the new variant of mpox? Following the World Health Organization (WHO), France placed its health system on maximum alert on Friday. While Sweden reported a first case on Thursday, others are expected to follow in Europe in the coming weeks, according to the WHO.

In this context, the international state of health emergency makes it possible to “motivate governments to facilitate access to vaccination and purchase vaccines in large numbers”Karine Lacombe, infectious disease specialist and head of the infectious diseases department at Saint-Antoine hospital, stressed on France Inter on Saturday. Franceinfo provides an update on the vaccination situation while the Ministry of Health announced on Saturday, August 17, that“none contamination by the [variant clade 1b] n / A[vait] yet been recorded” in the country for now.

An effective vaccine against the 2022 variant

A first mpox pandemic broke out in 2022. While the Covid pandemic required the manufacture of a new adapted vaccine, the smallpox vaccine proved effective against mpox, its distant cousin. Mandatory in France until 1979, smallpox vaccination (first and second generations) has ceased “because there were no more cases of human smallpox in the world. It is a disease that has been eradicated”recalls Brigitte Autran, professor emeritus in immunology and president of Covars, the Committee for monitoring and anticipating health risks, on France Inter.

Several scientific studies demonstrate the effectiveness of the “third generation” vaccination against mpox (variant “clade 2b”). A study by Inserm published at the end of July in The Lancet Regional Health-Europe concludes to “an estimated 99% reduction in incidence” in case of “rapid implementation of vaccination”. An American meta-analysis from June 2024 specifies that this makes it possible to “prevent serious illness and hospitalization”. An American study from May 2023 also suggests “that a series of two doses appeared to offer better protection”.

A probable protective effect against the new variant

The epidemic has taken a new turn: 18,737 suspected or confirmed cases and 500 deaths have been recorded since the beginning of 2024 in Africa, mainly in the Democratic Republic of Congo (DRC), according to the African Union health agency (Africa CDC). Will current vaccines be effective against the new clade 1b variant? More deadly and more transmissible than previous variants, its mortality rate can reach 5% in adults and 10% in children.

“We are equipped to face this epidemic with vaccines that will work”anticipates Brigitte Autran. “We know that this vaccine, which is called MVA, from the Bavarian Nordic company, protects against the variant or subtype of mpox that circulated in 2022-2023. We have very strong arguments to believe that it will protect just as effectively against the variant that has just emerged. (…) There is no reason why this vaccine should not works“, estimates the professor of immunology.

Sufficient stock in Europe…

The European continent is unlikely to suffer from a supply problem. Danish pharmaceutical company Bavarian Nordic, which manufactures the only vaccine approved in Europe and the United States, has announced that it has 500,000 doses in stock and is ready to produce up to 10 million doses by 2025. On Friday, the company also announced that it had applied to have its vaccine approved for adolescents.

On the French side, “There is no concern about access to the vaccine”estimates infectious disease specialist Karine Lacombe. “The vaccines are already available and we continue to use them. We have never stopped between 2022 and now.” At the Saint-Antoine hospital in Paris, where the infectious disease specialist works, “We have several hundred doses at the pharmacy waiting to be used. We have activated new vaccination lines.”she illustrates.

…but insufficient in Africa, the focus of the epidemic

Smallpox vaccines have been available in Africa for “very recently”, “with major logistical and financial constraints”lamented Xavier Lescure, an infectious disease specialist at the Bichat-Claude-Bernard hospital and member of Covars, on France Inter. However, he is not “not very worried” : “There is a level of responsiveness in pharmaceutical and vaccine companies that has proven itself for Covid, there will be aid, support, contributions that will ensure that the manufacture of the vaccine will be on track,” he anticipates. “It is very important to increase vaccine capacity”adds Brigitte Autran.

In its report to the WHO, the African Union health agency said: “a very explicit request for solidarity and equity between the countries of the North and the South”recalls Xavier Lescure. The professor, a specialist in infectious diseases at the University of Paris-Cité, evokes a contrast between the “optimal support in northern countries” and access to the vaccine “extremely limited, if not totally non-existent, in African countries” in 2022-2023.

Call heard: the European Commission announced in a press release on Thursday the sending of 215,000 doses of the Bavarian Nordic vaccine to the African Union health agency. And on Friday, Gabriel Attal also announced that France would “to donate vaccines to the most affected countries”, “in accordance with our values ​​of international solidarity and the health priority of containing the epidemic outbreak in Africa”.

A target population that is not expected to expand

Since the summer of 2022, only a section of the French population has been affected by preventive vaccination. According to an opinion from the High Authority for Health (HAS) dated July 2022, this is “multi-partner men who have sex with men (MSM), trans people reporting multiple sexual partners, sex workers, professionals in places of sexual consumption”. It can also be considered “for health professionals who are called upon to care for sick people”.

This part of the population vaccinated two years ago is “probably protected, although we do not know how long the effectiveness of this new vaccine will last”tempers Brigitte Autran. “A priori, as for the 2022 epidemic, it would be necessary to have a new injection of vaccine to have complete protection.” As for people born before 1975 and already vaccinated, “they have immune memory”she believes.

“There is no reason to open vaccination to the general population. There will be no major inflation of needs in the North”says Xavier Lescure. “In the South, it’s different, since the exposed population is much larger. (…) It’s on the exposed African populations [qu’il faut faire des efforts de vaccination].” The government has contacted the HAS to obtain vaccination recommendations adapted to the current situation.

The Ministry of Health reminds that since July 2022, a specific listening device for the mpox virus, responsible in particular for informing, advising and directing towards care systems, has been available. Monkeypox info service is accessible 7 days a week, from 8 a.m. to 11 p.m., on the toll-free number 0 801 90 80 69.