Research and analysis

Mpox (monkeypox) outbreak: epidemiological overview, 20 December 2022

Updated 7 March 2024

Data as of 19 December 2022

This epidemiological overview and the accompanying spreadsheet of counts of monkeypox (mpox) by region and upper tier local authority will be published for the last time on 20 December 2022, due to low case numbers and availability of alternative reports.

As mpox continues to be a notifiable infection, please refer to the UK Health Security Agency (UKHSA) notifications of infectious diseases reports for weekly updates (but not cumulative totals) on laboratory-notified mpox cases in England and on notifications of clinically suspected mpox in England and Wales by region and local authority. Further technical briefings will provide more detailed epidemiological analyses.

Mpox is a zoonotic infection, caused by the monkeypox virus, that occurs mostly in West and Central Africa. Previous cases in the UK had been either imported from countries where mpox is endemic or contacts with documented epidemiological links to imported cases. Between 2018 and 2021, there had been 7 cases of mpox in the UK. Of these, 4 were imported, 2 were cases in household contacts, and one was a case in a health care worker involved in the care of an imported case. There was no documented community transmission in previous outbreaks.

Current epidemiological situation as of 19 December 2022

Cases of mpox infection were confirmed in England from 6 May 2022. The outbreak has mainly been in gay, bisexual, and men who have sex with men without documented history of travel to endemic countries. Further details on the epidemiology are available in the mpox technical briefing.

To expand the UK’s capability to detect mpox cases, some NHS laboratories are now testing suspected mpox samples with an orthopox polymerase chain reaction (PCR) test (orthopox is the group of viruses which includes mpox). Since 25 July 2022, the mpox case definition recognises those who are orthopox-positive as highly probable cases, and those who test positive on a mpox PCR test as confirmed cases. The counts below combine both of these categories.

Up to 19 December 2022 there were 3,582 confirmed and 148 highly probable mpox cases detected in the UK: 3,730 in total. Of these, 97 were in Scotland, 34 were in Northern Ireland, 47 were in Wales and 3,552 were in England. There were no new cases of mpox in this update compared with 7 days prior.

Table 1: Number of confirmed and highly probable mpox cases by UK nation of residence, 6 May to 19 December 2022

UK nation Total* Confirmed* Highly probable*
England 3,552 3,404 148
Northern Ireland 34 34 0
Scotland 97 97 0
Wales 47 47 0
Total 3,730 3,582 148

*The numbers in brackets show change since last report (12 December 2022)

A high proportion of England cases were London residents (69%, 2,435 of 3,539 with location information). For confirmed and highly probable cases in the UK, where gender information was available, 3,653 (98.6%) were men and 53 were women. The median age of confirmed and highly probable cases in the UK was 36 years (interquartile range 30 to 44).

Table 2: Number of confirmed and highly probable mpox cases by region of residence, England, 6 May to 19 December 2022

Region of residence Total confirmed and highly probable cases Change since last report
East of England 123 0
East Midlands 66 0
London 2,435 0
North East 50 0
North West 231 0
South East 326 0
South West 93 0
West Midlands 131 0
Yorkshire and Humber 84 0
Under investigation** 13 0
Total 3,552 0

**Address not yet confirmed. Negative changes due to updates to location information.

Data sources

Mpox surveillance data in England is currently compiled daily, based on mpox and orthopox virus test results from the Rare and Imported Pathogens Laboratory (RIPL), which is the UK Health Security Agency (UKHSA) mpox reference laboratory, and other UK laboratories with mpox and orthopox testing. This is combined with case information recorded by local health protection teams in the UKHSA national case management system.

Counts of confirmed cases in Wales, Northern Ireland, and Scotland are submitted to UKHSA by Public Health Wales, Public Health Agency Northern Ireland, and Public Health Scotland respectively.

Information about this publication

This update is currently published on Tuesdays, using data extracted by 9.30am on Mondays.

These figures are used for official reporting of mpox confirmed case counts in the UK.

England counts may differ from those published in the Notifications of infectious diseases (NOIDs) causative agents weekly report. This is due to differences in timings of when the data is compiled, and differences in processing of duplicate data (for example, if a person has tested more than once but insufficient information is provided to identify them).

While data cleaning is carried out routinely, corrections can be applied between reports, such as updates to patient information and the removal of quality assurance samples from laboratory surveillance systems.

Additional resources

Mpox technical briefings.

Mpox: case definitions.

Mpox contact tracing guidance: classification of contacts and advice for vaccination and follow-up.