The monkeypox virus or monkeypox is currently causing several epidemics around the world and particularly in the United States and Europe.
According to the latest Public Health France report, 2,239 cases were identified in France as of Tuesday midday, including a majority of the cases (1,375) reported in Île-de-France. 45 cases were hospitalized, including 37 from complications related to monkeypox.
To prevent the introduction of this virus into French Polynesia, the country has authorized the marketing of the monkeypox vaccine, the specialty IMVANEX.
French Polynesia approves the vaccine that would make it possible to vaccinate the population identified as being at risk of contracting smallpox. award procedures are ongoing.
It is a vaccine against human smallpox, a deadly disease that was eradicated in 1980 and is currently used against monkeypox.
These two viruses belong to the “orthopoxvirus” family. The serum uses a third virus in this family that is genetically close to that of vaccinia.
The vaccine, harmless to humans, allowed the British doctor Edward Jenner in the 18th century to develop the very principle of vaccination (and create the first vaccine against smallpox): to educate the immune system by confronting the body with a nearby virus who is to be fought.
“Between the smallpox and monkeypox viruses there is 90-95 percent homology in the viral proteins involved. So taking a very narrow vaccine to block it is a proven strategy.” says Olivier Schwartz, head of the Viruses and Immunity department at the Pasteur Institute.
The current vaccine, made on cell culture and no longer on animals, “should be the third generation because it has been improved compared to the previous two to limit side effects,” specifies Yannick Simonin, lecturer at the University of Montpellier. Specialist in new viruses.
Smallpox infection confers cross-protection against the monkeypox cousin virus, a mechanism similar to that of smallpox vaccine against monkeypox.
Although large-scale data are not yet available, previous epidemiological elements and laboratory tests suggest that the current smallpox vaccine will be highly effective against monkeypox.
“The 85% protection figure comes from field studies in Zaire in the 1980s-1990s and is fairly approximate.”remarks Olivier Schwartz.
He also mentions studies on caregivers in 2018 and experiments on macaques that seem to show strong vaccination effectiveness after exposure to monkeypox.
Smallpox vaccination prior to 1980 provides a priori immune protection against monkeypox of uncertain magnitude and duration.
“According to studies, for example from the 2000s, antibodies against smallpox were found in 30 percent of people who were vaccinated at least 20 years previously,” says the Pasteur researcher. And “a booster dose activates memory cells — B or T lymphocytes — and reactivates cellular immunity, even after 20 or 40 years.”
However, Yannick Simonin warns against immunity “decreases over time and that the persistence of neutralizing antibodies to monkeypox has never been studied”.
The only vaccine currently approved for monkeypox is made by the Danish company Bavarian Nordic from the virus strain MVA-BN (modified vaccinia Ankara virus).
It is marketed as Jynneos in North America and Imvanex in Europe.
Several countries and the WHO are stockpiling smallpox vaccines for security reasons, particularly given a bioterrorism risk. Bavarian Nordic partnered with US government agencies in 2003 and has already shipped 30 million doses to them. Since the current monkeypox outbreak, an agreement provides for 7 million additional doses.
According to the WHO, there are currently 16 million doses of MVA-BN worldwide, mostly in large quantities that would take a few months before being bottled for use. It is difficult to know the state of the stocks, the countries that oppose defense secrecy, to the chagrin of associations and elected officials.
The details of the orders of the only current manufacturer are not known to us either. The EU has so far ordered 100,000 cans.
Bavarian Nordic has an annual production capacity of 30 million cans. Two other smallpox vaccines, LC16 and ACAM2000, manufactured by other laboratories are under investigation. Emergent BioSolutions, the American lab that makes ACAM2000, told AFP that it has an annual production capacity of 18 million doses, which could reach 40 million doses per year if needed.
Despite the presence of monkeypox-endemic areas in parts of the continent, more than 3,000 confirmed cases and more than 70 potential deaths according to doctors, Africa still does not have a dose of the vaccine.
The WHO has urged countries with vaccines “to share them with countries that don’t have them” and urged not to reproduce the Covid-19 scenario when rich countries have kept almost all vaccines available for many months.
“Is there a risk that the countries making (requests) for access are rich countries? It’s entirely possible.” Meg Doherty, director of WHO’s HIV, hepatitis and sexually transmitted infections programmes, ruled on Sunday, calling for “fairness” on monkeypox at an international AIDS conference.
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