After several months of the global outbreak of monkeypox, more is known about the disease. But many questions still await answers. We take stock.
In video: Monkey pox. Can we already speak of an epidemic?
The profile of the patients, too, stands out. These are mainly adult men and maintaining homosexual relations, in contrast to what has been observed so far in Africa, where the disease strikes many children.
A first question therefore arises: has the virus changed by dint of mutations, or has the current epidemic started rather by bad coincidences?
“By examining the genome, indeed there are some genetic differences”WHO told AFP this week.
“However, nothing is known about the significance of these genetic changes, and research is ongoing to establish the (possible) effects of these mutations on disease transmission and severity.”
Is it a sexually transmitted disease?
Researchers remain largely reluctant to label monkeypox a sexually transmitted disease (STD), but it is now clear that current contaminations are mainly linked to sexual intercourse.
This conclusion, on which converge several studies made from hundreds of cases, 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 currently the case in several countries including France.
But a major nuance remains: is the virus simply transmitted by skin contact during sexual intercourse, or can it pass through semen?
A few studies in recent weeks have isolated the virus from the semen of patients and in one of them it was still infectious. But they are too preliminary to conclude.
Is transmission to animals possible?
Originally, monkeypox was identified as a disease mainly transmitted to humans by animals, which are moreover rodents and rarely primates.
The high level of contamination between 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 constitute 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, it is only a single case and, according to the WHO, the danger would rather be that the virus spreads to wild and non-domestic animals.
“It is through the process of one animal infecting the next and the next and the next that you see a rapid evolution of the virus”pointed out this week Michael Ryan, a WHO expert.
Can you be contagious without symptoms?
It is unknown to what extent people infected with the virus, but without symptoms, can transmit it quietly.
Carried out in France, a study, published in the journal Annals of Internal Medicine, noted the presence of the virus in a few asymptomatic patients but without being able to say whether they were contagious.
It is already “an additional reason to consider monkeypox as a public health problem”estimated in the same journal Stuart Isaac, an independent researcher of the study.
How effective are vaccines?
Many countries have initiated vaccination campaigns. But these smallpox vaccines were not specifically developed against monkeypox.
Their degree of effectiveness therefore remains unclear even if there is little 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 (…) should have a significant effect on the transmission of the virus”British health authorities said this week, without it being possible to establish a direct link.