The World Health Organization (WHO) has given an update on the monkeypox situation, as confirmed and suspected cases continue to rise around the world.
Confirmed cases have now gone over 550, across countries where the disease is not endemic. The UK continues to be the hardest hit, with 106 cases that were reported by the WHO on Sunday climbing to 179, according to the UK Health Security Agency. Portugal has recorded 49 cases, while, in North America, Canada has recorded 26 cases and the US has reported 10.
Though monkeypox sees a relatively high number of cases per year where it is endemic – The Democratic Republic of Congo has seen 1,284 cases from January 1 to 8 May 2022, the WHO notes – what is unusual is seeing cases outside of countries where it is endemic, and there is no natural reservoir of animals that harbor the disease.
"What we're seeing now is really quite different," Rosamund Lewis, Technical lead for Monkeypox at the WHO Health Emergencies Programme, told CNN. "We're seeing cases all appearing in a relatively short period of time. We're seeing that in a few days, in a couple of weeks, we're seeing over 500 cases. This is different. This has not been seen before."
Though cases are already high, the WHO notes that cases should be expected to go higher still as surveillance expands in countries where the disease is non-endemic. While they stress that the overall public health risk is "moderate", the WHO said that the risk could become high if the disease establishes itself as a human pathogen, or if it spreads to vulnerable groups such as young children or the immunosuppressed.
They add that "there is likely to be little immunity to monkeypox among people living in non-endemic countries since the virus has not previously been identified in those populations". Vaccines that confer immunity for monkeypox include smallpox vaccines, meaning that so far only older members of society may have this protection, as the world stopped vaccinating once the similar (though more deadly) disease was declared eradicated in 1980.
"Smallpox and monkeypox vaccines, where available, are being deployed in a limited number of countries to manage close contacts," the WHO said in their update. "While smallpox vaccines have been shown to be protective against monkeypox, there is also one vaccine approved for prevention of monkeypox. This vaccine is based on a strain of vaccinia virus (known generically as modified vaccinia Ankara Bavarian Nordic strain, or MVA-BN). This vaccine has been approved for prevention of monkeypox in Canada and the United States of America."
The focus of health authorities around the world remains on monitoring and contact tracing to prevent further spread of the disease. As well as concerns about human-to-human transmission – which the evidence suggests is already taking place – some are worried that another animal or animals could act as a reservoir of disease.
“The natural reservoir of monkeypox remains uncharacterised to this day. Though, rodents and rabbits are known to be susceptible to monkeypox. Cats and dogs likely don’t get infected with monkeypox. Transmission to household pets such as hamsters, guinea pigs, chinchillas or rabbits should be avoided, as they would likely be ill, and may pass the virus to other people in the household," Prof Francois Balloux, Professor of Computational Systems Biology and Director of UCL Genetics Institute told Science Media Centre.
Balloux explains that the risk of monkeypox becoming a stable reservoir in household pets is low, as it requires sustained animal-to-animal contact that only occurs in nature or livestock.
“The emergence of a monkeypox reservoir outside Africa would require spill-over into commensal rodents, such as rats or mice or wild ones," he added. "This would be a highly unwelcome development, but it would be unlikely to involve an intermediate transmission event through household pets.”