Transmission of monkeypox virus through sexual contact – A novel route of infection

      In this Journal, Green and Cladi highlighted the need for international surveillance of zoonoses
      • Green S.T.
      • Cladi L.
      High time for an efficient and effective internationally-supported Zoonosis Surveillance System?.
      . With increasing travel and given the long incubation period, it is unsurprising that Monkey Pox (MPX) cases have been reported in over ten countries including the UK, however, the current outbreak is atypical in that the majority of cases are unrelated to travel with increasing prevalence in men who have sex with men (MSM). MPX is an Orthopox virus, endemic in West and Central Africa . On the 7th May 2022, the UK Health Security Agency (UKHSA) reported a classic case of imported MPX in an individual who had recently returned from Nigeria. Subsequently, many UK cases have been identified who were symptomatic before this individual was identified to have MPX. Between 2018 and April 2022, seven cases of MPX have been reported in the UK. At the time of writing, there have been 20 cases reported in the month of May 2022 alone

      UKHSA. Monkeypox cases confirmed in England - latest updates 2022 [Available from:

      MPX is classically transmitted through bodily fluids and close skin-to-skin contact from active lesions. While transmission during sexual intercourse has been suggested as a viable route, we report what we believe to be the first case of MPX infection with documented transmission through sex.
      Our case involves two white British men (patients 1 and 2) who report no recent travel outside of the UK and no history of travel to regions with endemic MPX. They were both fit and well, with Patient 2 having a history of well controlled HIV on antiretroviral treatment. At the time of condomless sexual contact at the end of April 2022, Patient 1 was the receptive partner and Patient 2 the insertive partner during both anal and oro-anal sex. Of note, ten days prior to sexual contact, Patient 1 reported kissing an unrelated individual who had a crusted oral lesion.
      Twenty-four hours after sexual contact, Patient 1 developed perioral white spots and painful perianal blistering lesions. Forty-eight hours later, Patient 2 had symptoms of perioral papules which blistered and ulcerated, with subsequent papules on the mons pubis and penile shaft which evolved into painful ulcers.
      Neither individual reported prodromal symptoms. Skin lesions at the point of sexual contact were likely to be the herald signs of infection and (atypically) followed by systemic features of lymphadenopathy, fever, headache and diarrhoea.
      Following the appearance of skin lesions, both patients presented separately to different sexual health clinics where the initial diagnoses of severe infection with herpes simplex virus (HSV) or varicella zoster virus (VZV) with superimposed bacterial infection were made. Both individuals were commenced on high-dose oral antiviral and antibacterial medication and managed in the out-patient setting.
      Patient 1′s cutaneous lesions were painful and remained localised to the perioral and perianal areas, with the latter having a mixed morphology- some displaying umbilication, others deroofed with exudate (see Fig. 1). There were no genital lesions. Patient 2′s symptoms persisted at the genital and pubic regions and the facial ulcers extended to involve the tongue, oral and buccal mucosae (see Fig. 2). The lesions mirrored the points of skin-to-skin sexual contact with very few papules appearing outside of these anatomical sites. Both patients deteriorated and required admission to hospitals in Newcastle and London. With patient consent, communication channels were opened between the two sites to allow for information sharing, ensuring concurrent treatment.
      Fig. 1
      Fig. 1Perioral and perianal lesions on Patient 1.
      Fig. 2
      Fig. 2Genital and perioral lesions on Patient 2.
      The temporal association of symptoms to sexual intercourse and the location of primary lesion sites matching those of sexual contact, led us to consider a sexually transmissible infection. Lesions from both patients were negative for HSV and VZV on RT-PCR and syphilis serology showed no active infection. Virological screening through respiratory RT-PCR, serology and in the case of Patient 2 who presented with a headache, CSF, was negative for all pathogens tested. The short incubation period, along with the presence of pustulo-nodular lesions and systemic symptoms, made disseminated gonococcal infection (DGI) a probable diagnosis at the time. In view of this, on admission, both patients were commenced on treatment with intravenous ceftriaxone. While Patient 1 showed significant improvement, Patient 2 continued to develop new lesions despite antibiotic therapy. Results from nucleic acid amplification testing and culture at oral, pharyngeal, rectal, and skin lesion sites were negative for Neisseria gonorrhoeae, leading to questioning of the DGI diagnosis.
      On the 14th of May, UKHSA published images of cutaneous MPX lesions which were recognised as being morphologically similar to those seen on the London patient. The admitting team liaised with UKHSA and the Rare and Imported Pathogens Laboratory and serum, lesion and urine samples were sent for MPX testing. Within 24 h, lesion swabs from both individuals were confirmed to be positive for MPX, and Patient 2 was transferred to a High Consequence Infectious Disease Unit. Both patients remained systemically well throughout their hospital stay. There were no recorded fevers following admission, white cell counts remained within normal limits and inflammatory markers were only mildly raised (CRP <100 g/L).
      As a non-endemic infection, all MPX cases in the UK are of significant interest, however, our cases raise additional concerns around the involvement of previously unaffected communities and subsequently exposed healthcare workers (HCW). With transmission through sexual intercourse potentially becoming a more common transmission route than previously recorded, it is likely that sexually active individuals of all demographics will be affected. As we describe, these presentations may not fall into the expected ‘fever in a returning traveller’ scenario with ulcerating lesions and hence MPX should be considered in the differential diagnosis of any at risk individual with a rash, further characterisation of the clinical features is vital to inform clinicians and aid rapid diagnosis. Given that MPX virus is a category 3 pathogen, it is imperative that HCW utilise appropriate PPE, receive relevant support and education with clinical pathways instigated to manage possible MPX cases. Rapid communication and diagnostics will be the greatest tools to ensure constructive collaborative efforts amongst clinicians to benefit staff, services and patients, and sensitive community engagement/education will be crucial to avoid stigmatising groups with higher incidence rates.

      Ethics and consent

      Both patients provided written consent for the use of their case details and medical images in this publication, and we are sincerely grateful to them for allowing us to do so.

      Authors’ contributions

      All listed authors made substantial contributions to the conception or design of the work; or to the acquisition and analysis of data for the work; and drafting the work or revising it critically ahead of submission for publication.
      All authors had full access to the data involved in the study and accept responsibility to submit for publication. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

      CRediT roles

      All authors contributed to this manuscript.
      JH – conceptualisation, Writing - original draft, Writing - review & editing; AB – conceptualisation, Writing - original draft, Writing - review & editing; CM – conceptualisation, Writing - original draft, Writing - review & editing; NB – Writing - review & editing; YW – Writing - review & editing; CS – Writing - review & editing; MB – Writing - review & editing; LSPM – Writing - review & editing; NM – Writing - review & editing; TR – Writing - review & editing; AW – Writing - review & editing; MN – Writing - review & editing; SD – Writing - review & editing; RJ – conceptualisation, Writing - original draft, Writing - review & editing, supervision; DAP – conceptualisation, Writing - original draft, Writing - review & editing, supervision; BMP – conceptualisation, Writing - original draft, Writing - review & editing, Supervision.

      Conflict of interest

      There are no known conflicts of interest associated with this work.


      There is no funding associated with this piece of work.


        • Green S.T.
        • Cladi L.
        High time for an efficient and effective internationally-supported Zoonosis Surveillance System?.
        J Infect. 2020; 81: 647-679
      1. WHO. Monkeypox 2019 [Available from:

      2. UKHSA. Monkeypox cases confirmed in England - latest updates 2022 [Available from: