Scientific answers are hoped to prove crucial in determining how well the epidemic can be contained. Here’s what we know so far to better understand the virus, its transmission, and what’s going on with vaccination with the questions that remain.
– Is it a new virus? Monkeypox, which occurs with fever and skin lesions, has been known for decades in several African countries. The novelty is that this year it has spread to many other countries, especially in Europe and America, up to today exceeding 35,000 cases. Some early deaths have been reported as part of the current outbreak.
The patient profile also stands out. These are mainly adult men and men who maintain homosexual relationships, contrary to what has been observed so far in Africa, where the disease affects many children.
A first question therefore arises: has the virus changed due to mutations or has the current epidemic started rather by bad coincidences? “Looking at the genome, yes, there are some genetic differences,” the World Health Organization (WHO) recently said. However, nothing is known about the significance of these genetic changes and research is underway to establish the (if any) effects of these mutations on transmission and disease severity. “
– Is it a sexually transmitted disease? Researchers remain largely reluctant to label monkeypox as a sexually transmitted disease (STD), but it is now clear that the current contaminations are primarily related to sexual intercourse.
This conclusion, on which several studies carried out on hundreds of cases converge, undermines the hypothesis of an important role of airborne transmission. This calls into question the interest of keeping patients in quarantine for weeks, as is the case in several countries.
But an important nuance remains: is the virus transmitted simply by contact with the skin during sexual intercourse or can it pass through sperm?
Studies have isolated the virus from patients’ semen, and in one of them it was still contagious. But they are too preliminary to conclude.
– Transmission to animals? Originally, monkeypox was identified as a disease transmitted to humans mainly by animals, which are also rodents and rarely primates. The high level of contamination among humans is a novelty of the current epidemic. But it remains to be seen whether humans can in turn transmit the disease to an animal. The question is not anecdotal, because animals could be a breeding ground for contamination in which the virus would continue to evolve in a potentially dangerous way.
A case study, published in the Lancet, recently described a first transmission from human patients to a dog: two men who infected their greyhound in Paris. For the moment, however, this is only one case and, according to the WHO, the danger would rather be that the virus spreads to wild and non-wild animals. “It is through the process in which one animal infects the next, the next and the next that we see the rapid evolution of the virus,” said WHO expert Michael Ryan.
– Contagious without symptoms? It is not known to what extent people infected with the virus, but without symptoms, can pass it on safely. Carried out in France, a study, published in the Annals of Internal Medicine, found the presence of the virus in some asymptomatic patients, but without being able to say if they were contagious. This is already “one more reason to consider monkeypox as a public health problem,” estimates the study’s independent researcher Stuart Isaac in the same journal.
– How effective are vaccines? Many countries have started vaccination campaigns. But these smallpox vaccines were not developed specifically for monkeypox. Their degree of effectiveness therefore remains unclear, although there is no doubt that they confer a certain level of protection.
Pending formal studies, however, encouraging signs are coming from the United Kingdom, where the epidemic seems to be slowing down. “These thousands of vaccines administered (…) are expected to have a significant effect on the transmission of the virus,” the British health authorities put forward, without a direct link being possible.
Julien DURY / AFP
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Scientific answers are hoped to prove crucial in determining how well the epidemic can be contained. Here’s what we know so far to better understand the virus, its transmission, and what’s going on with vaccination with the questions that remain. – Is it a new virus? Monkey pox, which manifests itself as …
