The ongoing global outbreak of monkeypox differs in several ways from historical 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 of this outbreak are among gay, bisexual, and other men who have sex with men, and most transmission has been associated with sexual activity. However, experts fear that if not quickly managed with testing, vaccinations and treatment, the virus could spread beyond this group and become endemic in more countries.
“We have shown that the current international case definitions should be expanded to add symptoms that are not currently included, such as sores in the mouth, on the anal mucosa and individual ulcers,” said the lead author of the study, Queen Mary University Professor Chloe Orkin. from London “Expanding the case definition will help doctors more easily recognize the infection and prevent people from passing it on.”
glossary
injuries
Small scratches, wounds or tears in the fabric. Lesions in the vagina or rectum can be cellular entry points for HIV.
inflammation
The general term for the body’s response to injury, including injury from infection. The acute phase (with fever, swollen glands, sore throat, headache, etc.) is a sign that the immune system has been activated by a signal that heralds infection. But chronic (or persistent) inflammation, even low-grade, is problematic because it is associated long-term with many conditions such as heart disease or cancer. The best treatment for HIV inflammation is antiretroviral therapy.
mucosa
Moist layer of tissue that lines the openings of the body, including the genital/urinary and anal tracts, the intestine, and the respiratory tract.
polymerase chain reaction (PCR)
Method of amplifying fragments of genetic material so that they can be detected. Some viral load tests are based on this method.
right
The last part of the large intestine just above the anus.
As previously reported by aidsmap, the UK Health Safety Agency (UKHSA) reported the first case of monkeypox in the current outbreak on 7 May. As of 18 July, UKHSA has identified 2137 confirmed cases in the UK. The European Center for Disease Control and Prevention 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 in worldwide, including 15,605 in countries that have historically not reported monkeypox.
Orkin and a long list of colleagues formed an international collaborative group of physicians (the SHARE-net Clinical Group) that provided data on monkeypox cases in 10 European countries, the US, Canada, Mexico, Australia, Argentina and Israel.
In total, they collected information from 528 cases diagnosed with a positive monkeypox PCR test between April 27 and June 24. Most were diagnosed in HIV clinics, sexual health clinics or emergency departments.
All but one person with monkeypox was male, and the remaining individual identified as trans or non-binary. There were no women in this series of cases, 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 straight.
The average age was 39 years. Fifty-six people were over 50 years of age, and 9% had previously received a smallpox vaccine, showing that prior vaccination is not fully protective. The authors did not say whether any were under the age of 18, but countries have reported a handful of cases among children. Three-quarters were white, 12% Latino, 5% black, and 4% mestizo.
Regarding HIV status, 41% were HIV positive. Of these, almost all (96%) were on antiretroviral therapy, most of them (61%) with an integrase inhibitor. Most had well-controlled HIV, with 95% having an undetectable viral load (less than 50); the median CD4 count was high at 680. Among the 59% of people who were HIV negative or had an unknown status, more than half were on pre-exposure prophylaxis (PrEP). Co-infection with hepatitis B (1%) and active hepatitis C (2%) was uncommon.
“Although people with HIV account for more than 40% of cases to date, it is reassuring that HIV status is not related to the severity of monkeypox,” said Laura Waters, president of the British HIV Association.
Transmission of monkey pox
According to the study authors, “transmission is suspected to have occurred through sexual activity” in 95% of people with monkeypox in this case series.
Monkeypox virus is transmitted through close physical contact, which may include skin-to-skin contact, exchange of body fluids, and short-range respiratory droplet transmission, although it is not spread by the ‘air at longer distances. The virus can also potentially be spread through clothing, bedding or surfaces that have been in contact with injury fluids, although this appears to be much less common. It is not yet known whether the virus is transmitted through semen or vaginal fluid. Before the current outbreak, monkeypox was not thought to be easily transmitted from person to person, but the sexual networks of men who have sex with men have provided a favorable environment for rapid transmission.
NAM aidsmap’s Susan Cole talks to Harun Tulunay, who shares his experience of being hospitalized with severe smallpox, and BHIVA president Dr Laura Waters about the virus.
In fact, this group had numerous sexual risk factors. Among those who had been tested for sexually transmitted infections (STIs), 29% tested positive, with syphilis (9%), gonorrhea (8%) and chlamydia (5%). Among people with a known sexual history, the average number of sexual partners was five in the previous three months. One in five reported “chemsex” (recreational drug use during sex) and 32% reported attending sex sites in the previous months. Just over a quarter reported traveling abroad in the month before diagnosis, mainly to European countries.
“Close sexual contact” was by far the most common suspected route of transmission (95%). About a quarter (26%) had contact with a person known to have monkeypox. Non-sexual close contact and household contact were 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; can be acquired through any type of close physical contact,” said lead study author Dr John Thornhill, from Barts NHS Health Trust and Queen Mary University of London. “However, our work suggests that most transmissions to date have been related to sexual activity, primarily but not exclusively among men who have sex with men. This research study increases our understanding of the ways in which it spreads and the groups in which it is spreading, which will help in the rapid identification of new cases and allow us to offer prevention strategies, such as vaccines, to those people at higher risk”.
Symptoms and treatment
Only 23 people diagnosed with monkeypox had a clear enough exposure history to determine the incubation time, which ranged from three to 20 days. The majority (97%) had positive skin swabs or anogenital lesions and 26% had positive nose or throat swabs. In addition, some had positive PCR tests from blood (7%), urine (3%) and semen (5%) samples.
However, “this may be coincidental, as we do not know [the virus] it’s present at high enough levels to facilitate sexual transmission,” Thornhill said. “More work is needed to understand it better.”
Almost all people with monkeypox (95%) developed a rash or lesions, including 73% with anal or genital lesions, 55% with trunk or limb lesions, 41% with mucosal lesions (mainly anal, throat or both), 25% with facial lesions and 10% with lesions on the palms or soles. However, 28 people (5%) did not develop lesions. Seventy-five people (14%) reported proctitis or rectal inflammation. Other common symptoms include fever (62%), swollen lymph nodes (56%), fatigue (41%), muscle aches (31%), headache (27%) and sore throat (21%).
Some individuals in the case series had symptoms not recognized in current medical definitions of monkeypox, including unique genital lesions and sores in the mouth or anus or inside. In some cases, these symptoms resemble those of common STIs, which could lead to misdiagnosis, and some people had chickenpox and STIs concurrently. The study authors emphasized the importance of educating health care 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 that caused difficulty swallowing (5 people); 13 were in hospital for quarantine. Two people each had eye injuries, acute kidney injury and myocarditis (inflammation of the heart muscle). Several men who have shared their stories in the press or on social media have described severe anal or throat pain.
Only a small number of people (5%) received antiviral treatment, which has been scarce and difficult to obtain. Two each received tecovirimat (Tpoxx) and cidofovir (Vistide), and one received vaccinia immunoglobulin (antibody therapy).
No deaths were recorded in this series of cases. So far this year there have been five deaths from monkeypox, all in African countries.
“Findings from this study, including identifying those at greatest risk of infection, will help aid the global response to the virus,” according to a press release about the report. “Public health interventions targeting this high-risk group could help detect and slow the spread of the virus. Recognizing illness, tracing contacts and advising people to self-isolate will be key components of the public health response “.
The authors of the study emphasized that public health measures should be developed and…