Intended for healthcare professionals


The changing face of monkeypox

BMJ 2022; 378 doi: (Published 10 August 2022) Cite this as: BMJ 2022;378:o1990

Linked Research

Clinical features and novel presentations of human monkeypox in a central London centre during the 2022 outbreak

  1. Larissa Mulka, consultant in sexual health and HIV1,
  2. Jackie Cassell, professor of primary care epidemiology2
  1. 1Department of Sexual Health and HIV, King’s College Hospital, London, UK
  2. 2Department of Primary Care and Public Health, Brighton and Sussex Medical School, Brighton, UK
  1. Correspondence to: L Mulka lmulka{at}

What should patients and clinicians look out for?

More than 50 years ago in 1970 the then US Surgeon General allegedly stated that we could “close the book on infectious diseases, declare the war against pestilence won and shift national resources to such chronic problems as cancer and heart disease.”

Luckily for William Stewart’s reputation the statement’s attribution remains unverified,1 since we continue to reel from the emergence of viral threats, including HIV and AIDS, Ebola virus disease, covid-19, and now an international outbreak of monkeypox. But not monkeypox as we know it, as Patel and colleagues (doi:10.1136/bmj-2022-072410) report in a series of 197 patients from the UK.2

The striking new distribution of clinical features and presentations reported in their linked paper differs from previously characterised outbreaks in the Democratic Republic of Congo3 and Nigeria.4 These changes may well lead to delayed diagnoses and avoidable onward transmission. Four out of five patients in the series sought care within the national network of genitourinary medicine clinics, established more than a century ago. A large proportion of these clinics’ workload is to encourage men who have sex with men to access regular testing for sexually transmitted diseases; vaccines, including for hepatitis B and human papillomavirus; and drug prophylaxis for HIV in accordance with risk.

In most towns and cities, genitourinary medicine clinics also provide HIV care and a range of wider sexual health services, including contraception. These clinics have emerged as the mainstay of outpatient risk assessment and testing for monkeypox, with disease in the remaining patients being diagnosed in hospital or through emergency departments. However, not all men who have sex with men will identify as being at risk, or will disclose this behavioural information to healthcare providers, or indeed recognise personal risk of exposure.5

So, what are the key features of monkeypox that every clinician should be aware of? Patel and colleagues report a strikingly high frequency of penile, perianal, and rectal symptoms, with or without initial skin lesions, and also penile oedema, rectal pain, and pain on defecation. Unlike in classic descriptions of monkeypox, the lesion count is often low at presentation, and atypical single lesions can mimic abscesses and other deep tissue phenomena. Sore throat, sometimes with tonsillar abscesses, occurs in a minority of patients, and is often severe.

A biphasic timing of clinical features can also complicate diagnosis—patients in this study often had skin lesions at different phases of development. Systemic symptoms also differed from those of earlier outbreaks, with expected prodromal symptoms often absent and instead emerging with or after skin signs and other symptoms. The 10th of patients admitted to hospital for supportive treatment largely required pain relief and symptom control for penile swelling and rectal pain, some experiencing substantial secondary bacterial infection.

The UK Health Security Agency has updated its case definition as the outbreak has evolved,6 and a responsive approach will continue to be essential. Widespread awareness among clinicians of these emerging presentations will be even more important in the many jurisdictions globally where specialised genitourinary medicine services are not widely available.

Patel and colleagues’ study confirms the importance of testing people with monkeypox for sexually transmitted infections (STIs).7 Alternative causes of penile and rectal symptoms were common—an STI was also diagnosed in more than three in 10 patients. Interestingly, half of men testing negative for monkeypox virus were found to have an STI accounting for their symptoms, most frequently herpes simplex, syphilis, or gonorrhoea. The high prevalence of STIs, pre-existing HIV, and age distribution is reminiscent of the emergence of lymphogranuloma venereum in 2004, although from the limited sexual contact and ethnic distribution data reported in this series, similarities in the dynamics of the two outbreaks remain unconfirmed.8

Prevention in the form of targeted vaccination to break transmission chains offers hope for the control of the UK’s current outbreak if challenges in supply and distribution of smallpox vaccines can be overcome. Smallpox vaccines provide cross protection against monkeypox. The new study corroborates other evidence that infections are occurring predominantly among higher risk men who have sex with men.9 This pattern enables vaccine prioritisation, which may need flexibility if and when new at risk groups emerge.10 Vaccination must be delivered sensitively to avoid the kind of stigmatising public health messaging used early in the HIV epidemic. Creative approaches will be needed to ensure equitable distribution to people at risk who have poorer access to services or health literacy, both in the UK and globally.11

The distribution of cases, clinical characteristics, and patterns of accessing care seen in this study confirms a central role for genitourinary medicine clinics in the response to monkeypox, including contact tracing. Investment is urgently required. Wider sexual health services are being limited as resources are reoriented to the monkeypox response, causing major concern for public health leaders in the UK.12


Sexual health patient advocate David Crundwell kindly commented on an earlier draft of this manuscript.