How is monkeypox transmitted? Are there specific symptoms for the current outbreak? After a few months of the epidemic, we begin to learn more, with confirmation: the current contagions are mainly related to sexual intercourse.
Three months into the epidemic, nearly 28,000 cases have been confirmed worldwide and the first deaths are beginning to be reported. In this context, it is important to better understand the disease in order to better combat it.
– Which profile? –
Monkeypox has certainly been known in about ten African countries for several decades.
But the current epidemic has many distinctive features, the first of which is the profile of the patients.
These are mostly adult males engaged in homosexual relationships, in contrast to what has been observed in Africa, where the disease is particularly prevalent in children.
In recent weeks, three studies published in leading medical journals – the British Medical Journal (BMJ), the Lancet and the New England Journal of Medicine (NEJM) – have painted a clinical picture of the current epidemic from early work and from a few hundred cases manufactured.
They confirm that the disease mainly affects men with homosexual relationships. In each study, they represent almost all patients.
– What transmission? –
The dominance of this profile is not surprising since, largely documented by initial observations, it has largely guided health authority recommendations.
First of all, it leads to another question. Since the common point of the patients for the time being is their sexual activity, is the disease transmitted through them?
The issue is sensitive because some public health professionals fear they are stigmatizing homosexual people by attacking their sexual relationships.
But recent studies are clear. “Our work supports the idea that physical contact during sexual activity is the dominant mechanism for transmission of monkeypox,” summarizes the Lancet study, which was conducted in several Spanish hospitals.
In particular, this conclusion is based on the fact that the viral load in the patients’ skin lesions was much higher than in their airways.
The observation therefore seems to undermine the idea put forward by some researchers that airborne transmission also plays an important role in contamination.
However, this does not mean that the disease is seed-borne. The hypothesis is not ruled out, but current research is far from proving it.
– What symptoms? –
The three studies also confirm that the current epidemic is characterized by its symptoms.
They “are different from those observed in African populations affected by previous epidemics,” summarizes the BMJ study, whose observations were made in the UK.
Certainly, two central elements of the disease largely remain: an attack of fever, sometimes accompanied by muscle pain, and lesions on the body, which then turn into scabs.
But the details vary and the issue is certainly related to that of transmission, as newer patients experience certain physical manifestations associated with contamination during sexual intercourse.
In each study, the lesions are often concentrated on the anus, penis, and mouth. In addition, there are complications that have rarely been observed until now: inflammation of the rectum or penile edema.
What is the severity of the disease? Almost 40% of cases were the subject of complications, according to the Lancet study, and a fifth were hospitalized, according to the NEJM.
With the latter, however, “no serious complication has been identified,” tempering this latest work and evoking “reassuring” data.
– What uncertainties? –
Although this work provides a better understanding of the disease, many questions remain unanswered.
This applies in particular to the effectiveness of vaccines. The Lancet study shows that a significant proportion (18%) of patients had received a smallpox vaccine that was said to protect against monkeypox.
But the lag between vaccination and the disease, sometimes several decades, may explain this lower level of protection.
In conclusion, it remains to be seen whether one runs a higher risk if one has another disease. Almost half (40%) of the patients examined in the Lancet were thus infected with HIV. But it’s impossible to know if there’s a direct connection or a simple correlation.