Researchers from Imperial College London recently published a comprehensive case series on monkeypox. For this purpose, 528 infections were screened that were diagnosed between April 27 and June 24 in 16 countries. Overall, 98 percent of gay or bisexual men were affected. The average age was 38, the scientists report in the journal “NEJM.”

According to the publication, the virus was transmitted during sexual activity in 95 percent of cases. However, other transmission routes are also possible, for example through droplets or exposure to specific skin lesions. “It is important to emphasize that monkeypox is not a classic sexually transmitted disease (STI), it can be transmitted through any type of close contact,” said study author Dr. John P. Thornhill in a statement to Queen Mary University of London.

Symptoms vary among sick people

Patients’ symptoms were not always typical: 95 percent had skin lesions, of which the majority (64 percent) had fewer than 10 lesions. 73 percent had sores on the anus and genitals, with about 10 percent of patients experiencing only one lesion. The latter are similar in symptoms to other sexually transmitted diseases, which is why they are easy to confuse, the authors emphasize. Medical professionals should also consider monkeypox if these symptoms occur in high-risk individuals.

Patients also commonly had fever (62 percent), drowsiness (41 percent), muscle aches (31 percent), and headache (27 percent). Thirteen percent of patients had to be hospitalized, some with severe pain in the anus and rectum, severe sore throat, difficulty swallowing, or eye sores. There were three serious complications: one patient developed epiglottitis (inflammation of the back of the throat) and two developed myocarditis (inflammation of the heart muscle).

The European Epidemic Agency ECDC already reported in a report on 8 July that the current monkeypox outbreak is presenting the disease with a spectrum of symptoms that is different from previous monkeypox outbreaks in endemic countries. There are also asymptomatic or subclinical courses. The ECDC says the latter should be confirmed and the relevance of the transmission checked. Asymptomatic infection would make outbreaks particularly difficult. The current case series does not provide any information on this – only those infected were included who sought medical treatment for symptoms.

Source: DOI 10.1056/NEJMoa2207323