The encouraging signs are definitely there. The monkeypox epidemic continues to slow around the world, although new cases are appearing in some countries hitherto spared, such as Egypt and Ukraine. According to the WHO dashboard which lists all confirmed cases, as of September 7 there were 54,709 cases and 18 deaths recorded in 125 countries, 98% of them in Europe and North America.
According to latest figures given by Public Health France, published on September 15, 3,898 confirmed cases of Monkeypox have been identified in France, i.e. 113 additional cases since the report on September 8. The epidemic is marking time: while nearly 500 cases per week were detected at the start of the summer, only a little over a hundred are now. However, the authorities feared the effect of the summer, with its large gatherings.
How to explain this rather frank decrease in the number of cases of Monkeypox? For virologist Yannick Simonin, a specialist in emerging viruses at the University of Montpellier, the main reason is “probably the information and communication campaign around monkey pox”. “The authorities and the media have rightly spoken a lot about this epidemic. As a result, the most exposed populations have been very widely sensitized and this has probably resulted in a reduction in risky behavior, with more caution and screening” , he explains to L’Express.
On the other hand, according to Yannick Simonin, vaccination has not played a major role in the continuous drop in the number of detected cases observed for several weeks, even if “we lack perspective” on this question: “We can rule out a massive effect of the vaccination because the campaign started relatively late and we do not have enough feedback on the vaccine efficacy after one or even after two doses.
The share of infected women, a data to “closely monitor”
So far, the epidemic has remained largely confined to men who have sex with men. Thus, the vast majority of confirmed adult cases identified to date are male and 86 cases (2.2%) are female, specifies Public Health France in its last update. In addition, 9 cases in children under the age of 15 have been reported.
In its previous information point dated September 12, Public Health France specified that “among all the confirmed cases declared in week 36, 12.9% were women, against 5.7% in week 35, 7.5 % in week 34 and 5.8% in week 33. Even if “these data must be interpreted with caution” due to a low number of cases detected in women, this data is however “to be watched closely” underlines Yannick Simonin, who wonders: “Is this the beginnings of a somewhat more general spread of monkeypox?”
The virologist calls for “remaining cautious” and “not declaring victory too soon”. “The virus is still circulating and a relaxation of behavior, with fewer vaccinations and fewer screenings, could promote the wider spread of the virus and could potentially fuel an epidemic resumption”, he warns. He adds: “We are not yet in a situation where we can say that everything is under control.”
“We are seeing a drop in the doses injected so we have probably reached the people most in need of being vaccinated. And if the cases drop as at present, vaccination will perhaps slip,” notes this specialist in emerging viruses. In addition, the vaccination campaign “has an important role to play over the long term” in order to control the epidemic, he recalls. “The more vaccinations there are, especially on the populations most at risk, the more we will reduce the risks of maintaining the epidemic within these populations.”
The animal reservoir risk
Monkeypox has yet to reveal all of its mysteries. The specialist in emerging viruses at the University of Montpellier thus recalls that “we do not yet know whether the virus is transmitted by the sexual act itself or by prolonged contact during the sexual act”. “If it is a virus that is sexually transmitted, then it is present in seminal fluid or in vaginal secretions and therefore this means that people who have no or few symptoms could potentially transmit it.”
If monkeypox “is not known as being a disease with a significant percentage of asymptomatics”, here again, specialists lack reliable data on this point, which is nevertheless important for better understanding and thus better controlling the dynamics of transmission. “Does the share of asymptomatic people play a role in the dynamics of transmission of the virus? We do not yet have clear answers”, summarizes Yannick Simonin.
Another “source of vigilance and concern” for health authorities: the question of the reservoir of the virus in the animal population. Even if, currently, “the transmission is human-to-human”, recalls the virologist, monkey pox can be transmitted from man to animal as well as in the opposite direction. “The more the virus circulates, the more there is a risk that the animals will be infected”, recalls Yannick Simonin. “Domestic animals could potentially transmit smallpox to wild animals which would then make a reservoir of the virus in the animal population and which could allow it to become endemic”, he explains. A worrying scenario, unlikely, but which cannot be ruled out.