Sixteen NHS hospitals have joined forces to describe their experience of the clinical features and management of more than 150 patients who needed hospital treatment during the recent outbreak of mpox.

An analysis of 156 patients with the condition who were admitted to hospitals in the UK during May, June and July 2022 has been published in the Lancet Infectious Diseases journal.

It is hoped that the findings will help improve understanding of the disease and have a positive impact on the care which can be provided in the future.

Key findings described in the paper include:

  • Clinical and laboratory features, including virological data for patients hospitalised with severe monkeypox, some of whom received treatment with the antiviral drug tecovirimat
  • All patients survived their mpox virus infections, but severe pain and secondary bacterial infection were experienced by more than half and many patients required strong pain killers and/or antibiotics
  • Around one third of patients were people living with HIV, although most had well-controlled HIV infection and were not immunosuppressed
  • Unusual complications included two cases of encephalitis (thought to be caused by mpox virus), five cases of severe eye disease, and ten patients who required surgery, typically to remove infected, dead areas of skin or other damaged tissue to help promote recovery from infection
  • Abnormalities in blood liver function tests were seen in one third of patients, although the reasons for these abnormalities are not clear and may differ between patients

Since 2018, patients in England requiring in-hospital care for mpox have been admitted to NHS England’s network of high consequence infectious disease (HCID) treatment centres. When case numbers increased significantly during the 2022 outbreak, specialist regional infectious disease centres and other hospitals with specialist infection services also provided care, as part of a larger clinical network and following the same infection prevention and control measures to prevent onward transmission within hospitals.

Dr Jake Dunning, consultant in infectious diseases at the Royal Free London, honorary clinical associate professor at UCL and senior research fellow at the University of Oxford, is the senior author for the paper. He said: “Since we diagnosed the first reported case of mpox in the UK in 2018, our specialist centres have continued to prepare for and respond to further cases of mpox.

However, the 2022 outbreaks of clade IIb mpox occuring outside Africa, which have to date mostly affected gay, bisexual, and other men who have sex with men, were truly unprecedented and were not predicted.

“Along with recurring mpox outbreaks in countries in West and Central Africa, this is why the WHO declared monkeypox a public health emergency of international concern in July.

“Sharing the findings from this collaborative study will help ensure that NHS hospitals - and clinicians in other countries - are aware of complications that can occur and the type of care that may be required, helping to improve preparedness for future cases and outbreaks. Most importantly, we hope this will help improve care and outcomes for individuals affected by mpox.”

Dr Mike Beadsworth, consultant in infectious diseases at the Royal Liverpool University Hospital, which is the lead centre for the Airborne HCID Network, said: “This paper shows the value of a specialist clinical network – in this case, initially the airborne HCID treatment centres and then, as patient numbers increased, a wider network involving specialist regional infectious disease centres and other hospitals with specialist infection services.

“All the hospitals supported each other and shared knowledge and information in real time. For this study, the hospitals worked quickly to examine their own experiences of managing hospitalised patients with mpox and submit anonymised data from those evaluations for a pooled analysis. This is the culmination of a great collaboration between this network, public health colleagues, and colleagues in sexual health clinics, as we responded to yet another outbreak of an emerging infectious disease.”

The lead author for the paper, Dr Doug Fink, is a clinical lecturer in Infectious Diseases at UCL and helped care for patients with mpox at the Royal Free Hospital.  He said: “Although this was not a prospective research study, our study shows the value of both sharing and analysing experiences of caring for patients, particularly during a novel outbreak. Thankfully, all the patients described in this paper recovered from their mpox illnesses, but that is not the case in all parts of the world; other countries have reported severe disease and sadly some deaths, mostly in people living with HIV and who are immunosuppressed.

“In addition to expertise in identifying, treating, and preventing emerging infections like mpox, people living with HIV in the UK have access to excellent medical care, which may explain why we have seen very few people with untreated, advanced HIV infection and severe mpox.

“Although clinicians elsewhere have published important descriptions of mpox, mostly in non-hospitalised patients, our clinical network has described a large series of patients with more severe disease, representing most of the patients with mpox in England and Northern Ireland who needed in-hospital care during the first three months of the 2022 outbreak. Our study provides the best estimate of the proportion of known mpox patients in the UK who had more severe illness requiring care in hospital - around 5-6% for the period studied.”

The infectious diseases team at one of the hospitals involved in the study, St Thomas’ Hospital, London, provided care to many patients with mpox in 2022. Charge nurse Jack Potter, said: “Although HCID and other emerging infectious disease outbreaks can be very challenging, we were able to provide expert care, safely, to over 35 patients on our specialist ward. Additionally, we were able to offer our patients access to new antiviral treatments when indicated, psychological support if it was needed, and opportunities to participate in clinical research. The large number of authors on this paper shows just how many people from different disciplines, including nursing, are involved in responding to these sorts of outbreaks. My team and I are proud to be part of the NHS response to mpox.”