Britain has urgently stockpiled on mpox vaccines as an expert warned the more menacing strain of the viral virus has 'very likely' already arrived on British shores.
NHS staff have also received guidance from the UK Health Security Agency to ensure they recognise symptoms of the Clade 1 mpox variant.
The disease, which experts say spreads faster and has a higher mortality rate than the previous outbreak two years ago, has been detected in Sweden and Pakistan.
First identified in the Democratic Republic of Congo, the latest mpox variant is thought to be the most dangerous thus far.
Initial symptoms are flu-like. A rash, which often starts on the face, then spreads around the body, leading to systemic infection.
Harun Tulunay spoke of his 'horrendous' symptoms with mpox in 2022 as a new wave has 'likely' arrived on British shores according to experts
Britain has stockpiled mpox vaccines and treatments to prepare for a dangerous new strain of the virus that has sparked a global health emergency
An image from 1997 shows symptoms of mpox on a sufferer in the Democratic Republic of the Congo, formerly Zaire
A former mpox victim Harun Tulunay, who was struck down by the virus when it was last in Britain, has told of his 'horrendous' ordeal.
He initially suffered from flu-like symptoms, such as muscle aches and a high fever, but his condition began to take a turn when lesions emerged, with some appearing in his throat.
Reliving the 'really scary' experience, he claims it was a challenge to get medical staff to take his condition seriously, as misdiagnosis meant he was denied an ambulance several times.
'After two weeks of horrendous high fever and pain, I wasn't able to move or drink or eat anymore - at that point I was hospitalised,' he told Sky News.
However the hurdles didn't stop when he finally received treatment, as it took three days for Mr Tulunay to receive an accurate diagnosis.
'After 11 days in hospital I felt better and I further isolated for two weeks at home until all the scars disappeared and I was fully healed,' he said.
He is now free from the short-term virus and all that remains is a small mark on his nose, but he believes vaccines for mpox should be widely launched especially in Africa.
The former mpox victim has been vaccinated against the virus due to the severity of his case in 2022.
'If there (was) a vaccine available in Africa, we wouldn't be facing a 2024 version of mpox right now,' he added.
Studies suggest up to ten per cent of infected children, and five per cent of adults, have died due to the new strain in central and southern Africa, where porous borders have assisted transmission.
More than 500 are thought to have died in the Democratic Republic of the Congo alone.
Reliving the 'really scary' experience, Mr Tunulay (pictured in hospital) claims it was a challenge to get medical staff to take his condition seriously
Jean Kakura Biyambo, a father of six from the Muja internally displaced persons camp in DRC, gestures from a general hospital where he has been receiving treatment for mpox, on July 16
The European Centre for Disease Prevention and Control warned all governments to expect cases, and one patient has been identified in Sweden.
Professor Paul Hunter, a specialist in medical microbiology, told Sky News that it is 'very likely' that someone in Britain already has the new variant, although it will probably be a few weeks before that is confirmed. He said infection risk was 'very low' unless people had multiple sexual partners.
A Home Office spokesman declined to comment on whether Border Force strike action, due to begin on August 31, could affect the interception of potential mpox carriers seeking entry to the UK, adding: 'We are committed to continuing conversations with the union.'
Typically found in central and east Africa, mpox has blighted populations since the early 1970s. While a vaccine now exists for the disease, uptake has been slow in nations lacking the resources and infrastructure for a coordinated programme.
Nearly 100,000 people were infected in 2022 during a global outbreak of the disease, caused mostly by the Clade IIb virus. The variant was less deadly than the emerging Clade Ib variant, but killed some 183 people, according to the US Centres for Disease Control and Prevention.
The United States reported as many as 32,063 cases, with 58 deaths during the period as cases were reported in significant numbers in North, Central and South America, Europe, Africa, Asia and Australasia.
Now, experts following recent trends warn a more deadly variant is showing both a propensity to travel across borders with a five per cent mortality rate in adults and ten per cent in children.
Vials of single doses of the Jynneos vaccine for mpox are seen from a cooler at a vaccinations site in Brooklyn, New York on August 29, 2022 as the disease swept through the United States
File. Mpox causes painful pus-filled blisters. A new variant has a 10% mortality rate in children
While the 2022 strain was largely driven by male-to-male sexual contact, according to The Economist, the Clade Ib variant appears to be transmissible through close non-sexual contact, and exacerbated by heterosexual sexual contact, 'particularly among sex workers, who account for about 30 per cent of recorded cases'.
Authorities in the DR Congo desperately approved mpox vaccines to try to contain the outbreak in June, passing 1,000 deaths from 20,000 cases within the past year, but many worry the affected nations lack the resources to effectively stop the spread in its tracks.
Zeil Rosenberg MD, executive Vice President of Tonix Pharmaceuticals, a company currently developing an mpox vaccine, told MailOnline that the disease is now spreading to regions where historically it has not been endemic, driving concern of a repeat of the deadly 2022 outbreak that infected nearly 100,000 people.
'The Democratic Republic of Congo (DRC) remains the centre of an unchecked explosion of cases with 11,000 cases reported this year alone and showing no signs of slowing,' he warned.
He explained that there are two 'clades' of mpox currently in circulation. The first carries more severe symptoms and a mortality rate of up to ten per cent. The second, responsible for the 2022 outbreak, is less lethal but has been able to thrive outside of Africa in the past.
'The most severe and lethal Clade 1 mpox, historically endemic to central Africa..., has become predominant and is now found throughout the region,' he warned.
Professor David Heymann at the London School of Hygiene & Tropical Medicine (LSHTM) told MailOnline that mpox could soon 'fill the epidemiological niche left by smallpox', with the vaccine no longer effective in preventing cases.
'Person-to-person transmission is now occurring and if persons with infection travel to other countries, the same situation regarding smallpox vaccination exists... outbreaks of person-to-person transmission could occur.
'As the infection is thought to have a fatality rate of 10 per cent, and higher in those living with HIV infection, the risk of serious impacts is high.
'Though the world joined together for mpox outside Africa, the situation in Africa continues to be neglected at a risk to persons in DRC.'
Children have been the main victims of the disease in the DRC, suffering 67 per cent of the cases and 78 per cent of reported deaths.
'Clade 1b has demonstrated evidence of sexual transmission, both gay and bisexual men and in heterosexuals, and the potential for global spread is significant,' added Dr Rosenberg.
Brian Labus, Assistant Professor at the University of Nevada Las Vegas' Department of Epidemiology and Biostatistics, said the new variant could spread through contact with infected animals, consumption of contaminated meat, and non-sexual contact between people.
Sufferers of the new, more deadly strain have all presented with rashes. More than half have had fever and/or swollen lymph nodes, and 'the vast majority' had genital lesions.
But the rise of asymptomatic cases has 'raised the level of concern' that the disease could cross borders unchecked without the means to identify and quarantine carriers.
These cases have been 'harder' to detect in the laboratory, with testing methods proving unreliable and posing further challenges to those working to contain the outbreak.
Of growing concern is the propensity for displaced persons within the DRC to move across its 'porous borders', fleeing conflict or its outcomes, and spreading the disease faster than authorities can act to curtail it.
The NHS is now urging people who have travelled to west Africa in the past three months, and who display symptoms, to see a doctor urgently amid fears the virus could spread out of Africa.
'As with the global epidemic of 2022-23, travel between countries is a prime cause of cross-border transmission, Dr Rosenberg warned.
'Considering that mpox has an incubation period of 1-2 weeks, seeing a doctor if symptoms develop within 3 weeks of travel, and receiving appropriate immediate antiviral treatment, is a prudent measure both for personal and public health reasons.'
As it stands, the means to stop the spread have not developed significantly since the 2022 outbreak. Vaccine availability remains 'remarkedly absent on the African continent', with little sign of improvement in the last two years, Dr Rosenberg said.
'Lack of international aid, vaccine inequality - where the developed country scoops up all the mpox vaccine at the expense of developing countries - and lack of infrastructure to support vaccine rollout efforts all play a role in the anemic response to-date.'
Tonix Pharmaceuticals is among the pioneers of a hopeful next-generation vaccine, designed in one version as a single dose, thermo-stable patch that will allow self-administration and go some way to managing the spread of the disease.
But two years on from an outbreak that could not be contained within central Africa, fears mount a deadlier strain, harder to detect, will test the strained resources of the DRC and its neighbours.
