The UK is considering a ring vaccination strategy to contain any further cases of a new and more dangerous strain of mpox after four people tested positive in London.
The approach, used successfully in past outbreaks of smallpox and Ebola, involves vaccinating contacts of confirmed cases – like neighbours, friends, and colleagues - forming a “ring” around the positive case to stop further spread.
At the moment known cases are small enough in number just to be isolated in specialist hospital wards.
If implemented, the strategy would focus on preventing imported cases of the Clade 1b strain—currently spreading rapidly in parts of Africa—from spilling over into the wider UK population.
“We are looking at a ring vaccination strategy to control the virus if more cases are detected in the UK,” a well placed government source told The Telegraph.
“It could involve vaccinating a dozen to a hundred people around each case, depending on how many people an infected individual has been in contact with,” the official explained.
“Ring vaccination in certain situations ought to be a really good tool, but it’s going to take more understanding of what populations the new strain of mpox is affecting,” they added.
If clade 1b demonstrates the ability to spread more broadly beyond initial cases and their immediate contacts, the UKHSA will consider expanding the vaccination program to target specific groups, The Telegraph understands.
For example, in 2022, an outbreak of a milder strain, clade II, began to spread amongst gay and bisexual men. In response, UKHSA launched a targeted vaccination campaign and offered jabs to men at clinics in Manchester, London, and Brighton - where the virus was most prevalent - who had multiple sexual partners, participated in group sex or attended sex-on-premsises venues.
The strategy focused on an at-risk group, rather than the contacts of individual cases.
Four clade 1b mpox cases have been confirmed in the UK since late October. The first involved a patient who had recently returned from Africa, followed by three household contacts who were also infected. All are currently being treated in isolation units in London hospitals.
The mutant strain was first detected in the Democratic Republic of Congo (DRC) in late 2023. It is thought to be more transmissible and causes more severe illness than previous variants.
Over 25,000 cases of clade 1b and 1,000 deaths—primarily among children under 15—have been reported in the DRC, prompting the World Health Organization (WHO) to declare a global health emergency earlier this year.
The virus has spread to several African nations, including Uganda, Burundi, and Rwanda, as well as in Sweden, Germany, India, Thailand and the US in travellers who have returned from the affected region.
“While the risk of catching mpox in the UK remains low, if required the NHS has plans in place to expand the roll out of vaccines quickly in line with supply,” Steve Russell, NHS national director for vaccination and screening, said.
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