How is monkeypox spread? What are the specific symptoms of the current surge? Three months after the start of the pandemic, scientists begin to draw its contours.
Nearly 28,000 cases have been confirmed worldwide and the first deaths have already occurred.
– The profile –
Monkeypox has been known for several decades in a dozen African countries.
But the current epidemic has many peculiarities, starting with the profile of the patients.
It is mainly adult men who have homosexual relationships, in contrast to what happens in Africa, where the disease mainly affects children.
In recent weeks, three studies published in the main medical journals of reference -British Medical Journal (BMJ), Lancet and the New England Journal of Medicine (NEJM)- have described the clinical picture of the disease, although the data is early, obtained from a few hundred cases.
Studies confirm that almost all cases affect men who have homosexual relationships.
– How is it transmitted? –
The predominance of this profile is not a surprise because it had already been documented with the appearance of the first cases.
Is the disease therefore transmitted through sexual transmission?
Some public health specialists fear that a definitive answer will stigmatize the homosexual community.
But the most recent studies are clear. “Our work supports the idea that bodily contact during sexual activity constitutes the dominant mechanism of monkeypox transmission” in the current epidemic, summarizes the Lancet study, carried out in several Spanish hospitals.
The conclusion is based in particular on the fact that the viral load was much higher in the skin lesions of the patients, compared to that contained in their respiratory system.
Some researchers had advanced the idea that airborne transmission would also play an important role in contamination, but these discoveries call this theory into question.
That does not mean that the disease is transmitted through sperm. The hypothesis is not excluded, but current research has not proven it.
– What are the symptoms? –
The three studies also confirm that the current epidemic is distinguished by its symptoms, which “differ from those that have been observed in populations affected by previous epidemics” in Africa, explains the BMJ study, which was carried out in the United Kingdom.
Two key elements of the disease: fever, sometimes accompanied by muscle pain, and bodily injuries, which turn into crusts.
The details vary and the question is surely linked to transmission, because among recent patients some physical manifestations seem to be related to contamination during sexual intercourse.
In each study the lesions are concentrated in the anus, penis and mouth. Added to this are complications that have been rarely observed until now: inflammation of the rectum or edema of the penis.
About 40% of cases have complications, according to a Lancet study, while a fifth of patients required hospitalization, according to NEJM research.
According to this latest study “no serious complication has been detected.”
– Missing data –
Although these studies provide a better understanding of the disease, many unanswered questions remain.
The first is the efficacy of vaccines. The Lancet study shows that a significant proportion of sufferers (18%) had received a smallpox vaccine, which is supposed to protect against monkeypox.
Patients contract monkeypox sometimes decades after vaccination, which would explain the lower protection.
Finally, it remains to be determined whether there are more risks when the patient is suffering from another ailment. About 40% of the patients studied by the Lancet were infected with HIV. But it is impossible to know if there is a direct link or if it is a simple correlation.