Study shows spectrum of monkeypox symptoms

The ongoing global monkeypox outbreak differs in several respects from historic transmission patterns and typical symptoms previously seen in countries in Africa where the virus is endemic, according to the largest case series to date.

Almost all cases in this epidemic are among gay, bisexual and other men who have sex with men, and most transmissions have been associated with sexual activity. However, experts fear that if not managed quickly with testing, vaccination and treatment, the virus could spread beyond this group and become endemic in more countries.

“We have shown that current international case definitions need to be expanded to add symptoms that are not currently included, such as sores in the mouth, on the anal mucosa and simple ulcers,” said the lead author of the study, Professor Chloe Orkin of Queen Mary University. from London. “Broadening the case definition will help doctors more easily recognize the infection and thus prevent people from passing it on.”



Small abrasions, wounds or tears in the tissues. Lesions in the vagina or rectum can be cellular entry points for HIV.


A general term for the body’s response to injury, including injury caused by infection. The acute phase (with fever, swollen glands, sore throat, headache, etc.) is the sign that the immune system has been triggered by a signal announcing the infection. But chronic (or persistent) inflammation, even low-grade ones, is problematic because it’s been associated long-term with many conditions such as heart disease or cancer. The best treatment for HIV-related inflammation is antiretroviral therapy.


Moist layer of tissue lining the openings of the body, including the genital/urinary and anal tracts, intestine and respiratory tract.

polymerase chain reaction (PCR)

A method of amplifying fragments of genetic material so that they can be detected. Some viral load tests are based on this method.


The last part of the large intestine just above the anus.

As aidsmap previously reported, the UK Health Security Agency (UKHSA) reported the first case of monkeypox in the current outbreak on May 7. As of July 18, the UKHSA has identified 2,137 confirmed cases in the UK. The European Center for Disease Prevention and Control has reported 10,604 cases across the European region as of July 19, while the US Centers for Disease Control and Prevention has compiled a total of 15,848 cases worldwide, including 15,605 in countries that have not historically reported monkeypox.

Orkin and a long list of colleagues formed an international collaborative group of clinicians (the SHARE-net Clinical Group) who provided data on monkeypox cases in 10 European countries, the United States, Canada, Mexico, Australia, Argentina and Israel.

In total, they compiled information on 528 cases diagnosed with a positive PCR test for the monkeypox virus between April 27 and June 24. Most were diagnosed in HIV clinics, sexual health clinics or emergency departments.

All but one of the individuals with monkeypox were male, and the remaining individual identified as trans or non-binary. There were no women in this case series, although several dozen women with monkeypox have been reported from individual countries. Almost all said they were gay (96%), 2% were bisexual and 2% identified as heterosexual.

The median age was 39 years old. Fifty-six people were over the age of 50 and 9% had previously received a smallpox vaccine, showing that prior vaccination is not fully protective. The authors did not specify whether any were under the age of 18, but countries have reported a handful of cases in children. Three-quarters were white, 12% were Latino, 5% were black, and 4% were mixed race.

Regarding HIV status, 41% were HIV positive. Of these, almost all (96%) were on antiretroviral treatment, with a majority (61%) on integrase inhibitors. Most had well-controlled HIV, with 95% having an undetectable viral load (less than 50); the median CD4 count was high, at 680. Of the 59% who were HIV-negative or of unknown status, more than half were on pre-exposure prophylaxis (PrEP). Co-infection with hepatitis B (1%) and active hepatitis C (2%) was uncommon.

“While people living with HIV account for more than 40% of cases so far, it is reassuring that HIV status has not been linked to the severity of monkeypox,” said Laura Waters, chair of the British HIV Association.

Transmission of monkeypox

According to the study authors, “transmission was suspected to have occurred through sexual activity” in 95% of people with monkeypox in this case series.

Monkeypox virus is transmitted by close physical contact, which can include skin-to-skin contact, exchange of bodily fluids, and short-range respiratory droplet transmission, although it does not spread through the air. air over longer distances. The virus can also potentially be spread via clothing, bedding, or surfaces that have come in contact with fluid from lesions, although this appears to be much less common. It is not yet known whether the virus is transmitted through semen or vaginal secretions. Prior to the current outbreak, monkeypox was thought not to be transmitted easily from person to person, but the sexual networks of men who have sex with men provided a favorable setting for rapid transmission. .

NAM aidsmap’s Susan Cole speaks with Harun Tulunay, who shares his experience of being hospitalized for severe monkeypox, and BHIVA President Dr Laura Waters about the virus.

Indeed, this group had many sexual risk factors. Of those who had been screened for sexually transmitted infections (STIs), 29% tested positive, with syphilis (9%), gonorrhea (8%) and chlamydia (5%) being the most common. Among people with a known sexual history, the median number of sexual partners was five in the previous three months. One in five said they had done ‘chemsex’ (using recreational drugs during sex) and 32% said they had been to sex venues in the past few months. Just over a quarter said they had traveled abroad in the month before diagnosis, mostly to European countries.

“Close sexual contact” was by far the most common suspected route of transmission (95%). About a quarter (26%) have been in contact with someone known to have monkeypox. Close non-sexual contacts and household contacts were each suspected in 1% of cases, while 3% had an unknown route of transmission.

“It is important to emphasize that monkeypox is not a sexually transmitted infection in the traditional sense; it can be acquired through any kind of close physical contact,” said study lead author Dr John Thornhill, from Barts NHS Health Trust and Queen Mary University of London. “However, our work suggests that most transmission so far has been linked to sexual activity – primarily, but not exclusively, among men who have sex with men. This research study increases our understanding of the patterns of spread and the groups in which it is spreading, which will facilitate the rapid identification of new cases and allow us to offer prevention strategies, such as vaccines, to those most at risk.

Symptoms and Treatment

Only 23 people diagnosed with monkeypox had an exposure history clear enough to determine the incubation time, which ranged from three to 20 days. Most (97%) had positive skin or anogenital swabs and 26% had positive nasal or pharyngeal swabs. Additionally, some had positive PCR tests on blood (7%), urine (3%) and semen (5%) samples.

However, “this may be incidental as we do not know that [the virus] is present at levels high enough to facilitate sexual transmission,” Thornhill said. “More work is needed to better understand this.”

Almost all people with monkeypox (95%) developed a rash or lesions, including 73% with anal or genital lesions, 55% with lesions on the trunk or limbs, 41% with mucosal lesions (mainly anal, throat or both), 25% with facial lesions and 10% with lesions on the palms or soles of the feet. However, 28 people (5%) did not develop lesions. Seventy-five people (14%) reported proctitis or rectal inflammation. Other common symptoms included fever (62%), swollen lymph nodes (56%), fatigue (41%), muscle aches (31%), headache (27%) and headache. throat (21%).

Some people included in the case series had symptoms not recognized by current medical definitions of monkeypox, including single genital lesions and sores on or inside the mouth or anus. In some cases, these symptoms resemble those of common STIs, which can lead to misdiagnosis, and some people have had monkeypox and STIs simultaneously. The study authors stressed the importance of educating healthcare providers on how to identify and manage these new clinical symptoms.

Seventy people (13%) were hospitalized, mostly for management of severe rectal pain (21 people), soft tissue infections (18 people) or sore throat causing difficulty in swallowing ( 5 people) ; 13 were hospitalized in quarantine. Two people each had eye damage, acute kidney injury and myocarditis (inflammation of the heart muscle). Several men who have shared their stories in the press or on social networks described severe anal or pharyngeal pain.

Only a small number of people (5%) received antiviral treatment, which was rare and difficult to obtain. Two each received tecovirimat (Tpoxx) and cidofovir (You see) and one received anti-vaccine immunoglobulin (antibody therapy).

No deaths were reported in this case series. There have been five monkeypox deaths so far this year, all in African countries.

“The results of this study, including the identification of those most at risk of infection, will contribute to the global response to the virus,” according to a press release on the report. “Public health interventions targeting this high-risk group could help detect and slow the spread of the virus. Recognizing the disease, tracing contacts and advising people to self-isolate will be key parts of the public health response.

The study authors stressed that public health measures should be developed and implemented in collaboration with at-risk groups to ensure they are appropriate, non-stigmatising and avoid messaging that could drive the outbreak. in hiding.

“This international case series contributes to the growing evidence of how monkeypox is transmitted and in which population groups,” said PrEPster co-founder Dr. Will Nutland. “The research should serve as an additional call to properly provision our responses to monkeypox, including scaling up testing, treatment and vaccination programs, for key populations most affected by the virus.”

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