Monkeypox outbreak was waiting to happen, say scientists

After the end of the global vaccine for smallpox more than 40 years ago, there was a surge in monkeypox cases in the UK and beyond.

There were 14 new cases in England on Tuesday, bringing the total to 70 and one patient in Scotland. There are no cases in Wales or Northern Ireland.

The World Health Assembly declared the disease eradicated in 1980. In regions of central and western Africa where monkeypox is endemic, the vaccine campaign kept the disease in check.

The risk of a major outbreak has increased since the proportion of people protected against monkeypox has fallen.

Dr Romulus Breban is a researcher at the Pasteur Institute in Paris. In the Democratic Republic of the Congo, immunity to monkeypox fell from 85% in the early 1980s to 60% in 2012 according to mathematical modelling by Breban and his team in 2020. He wrote at the time that monkeypox was an ever-increasing threat for health security. More than 170 deaths and 4,000 suspected cases were reported in the year 2020.

Breban said that the immunity level is almost zero.

Only a few cases of monkeypox have ever been seen in the UK, all linked to travel from Nigeria. More than 300 suspected or confirmed cases have come to light in at least 16 countries since the first UK case was announced in May.

There are questions about whether the monkeypox virus has evolved into a more transmissible form. Scientists haven't found any evidence that this is the case, but they are studying the genetics of the virus to see if it has changed. Genetic studies show the virus matches strains that came to the UK, Singapore and Israel.

Prof David Heymann, a distinguished fellow at Chatham House's global health programme, said the outbreak appeared more of a chance event, with the virus being amplified once it got into a community of men who have sex with men.

Graham Medley, a professor of infectious disease modelling at the London School of Hygiene and Tropical Medicine, said there was unlikely to be the same infectious growth seen in the general population. He said the outbreak could continue for several months as contact tracing slows.

He said that we can expect twists and turns as the monkeypox outbreak continues. The longer the outbreak goes on, the more likely it is that monkeypox will find other niches.

Researchers in the UK have found promising signs that an anti-viral may help to reduce illness from the virus. Four of seven patients with monkeypox in the UK were given brincidofovir or tecovirimat, drugs developed to treat smallpox, in a study published in the Lancet Infectious Diseases.

Findings from three patients who received brincidofovir suggest the drug provided little clinical benefit and did not seem to reduce the duration of the illness. One patient who was treated with tecovirimat had a shorter hospital stay and appeared to have shed the virus for a shorter period of time.

Although only one patient was involved, the result for tecovirimat was a promising signal, according to Dr Hugh Adler, a co-author of the study.

He said that it was important to share the total of human experience with these drugs and monkeys.

The UK is offering a vaccine to people who have been diagnosed with monkeypox to reduce the risk of severe illness. The UK has 5,000 doses of the vaccine and has been ordered an extra 20,000 doses.