Monkeypox virus mutating more than expected, say researchers

NEW YORK • The monkeypox virus may be mutating more than expected, according to researchers in Portugal, as the number of cases rises across Britain and the United States.

Scientists said the latest strain of monkeypox, once confined to parts of Africa, has about 50 genetic variations compared with related viruses that circulated in 2018 to 2019.

They found that the virus is continuing to evolve during the current outbreak, including a number of small changes in the genetic code, minor gene variants and a deleted gene, according to a study published in Nature Medicine yesterday.

"It was quite unexpected to find so many mutations in the 2022 monkeypox virus," said Dr Joao Paulo Gomes of the National Institute of Health in Lisbon and one of the authors of the report.

"In fact, considering the genome characteristics of this type of virus, no more than one or two mutations are likely to emerge each year."

The virus is more stable and slower to mutate than the coronavirus that causes Covid-19. In the past, monkeypox had not spread easily from person to person.

It is still unclear how the mutations seen in the current monkeypox virus might change any of those attributes, or the severity of the disease it causes.

More research is needed to better understand the changes in the virus, the researchers said.

A cousin of the smallpox virus, monkeypox typically causes flu-like symptoms, followed by a rash that often starts on the face and spreads down the body. The illness can be deadly in some instances. Many of the current cases are primarily among men who have sex with men.

The authorities worldwide are tracking the evolution of the monkeypox outbreak and expanding vaccination to more at-risk groups to try to contain the spread of the virus, with more than 3,300 cases reported globally.

The emergency committee of the World Health Organisation was expected to announce soon whether it will declare the latest outbreak a public health emergency of international concern - its highest alert level.

The US Centres for Disease Control and Prevention, which is looking to expand the use of the monkeypox vaccine for children, said the virus was behaving as expected.

"We are sequencing all specimens that we can get our hands on," Dr Gregory Armstrong, director of the CDC's Office of Advanced Molecular Detection within the National Centre for Emerging and Zoonotic Infectious Diseases, said in an interview on Thursday.

Thus far, the CDC is getting specimens from public health laboratories, he said.

"All the evidence so far suggests the virus is behaving as we anticipated. It is much more stable than most viruses, and we don't anticipate that it is going to be mutating at the rate of Sars-CoV-2," he said, referring to the virus that causes Covid-19.

Taiwan's government yesterday confirmed its first imported case of monkeypox, a man in his 20s who had studied in Germany from January until this month.

Taiwan's Centres for Disease Control said the man flew back to the island on June 16 and returned home for mandatory Covid-19 quarantine for all arrivals.

On Monday, he developed symptoms such as a fever, sore throat and a rash, and sought medical attention. He was tested and confirmed to have monkeypox, Taiwan's CDC said in a statement.

He is now being treated in an isolation ward. His close contacts are showing no symptoms, it said.

In the Asia-Pacific, Singapore, South Korea and Australia have also reported cases. More than 40 countries where monkeypox is not endemic have reported outbreaks of the viral disease.

Colombia yesterday also confirmed its first three cases of monkeypox in adults who had travelled from Europe and are now in quarantine, the country's Health Ministry said. Two of the cases were found in the capital Bogota, and the third was found in Colombia's second-largest city, Medellin.

Monkeypox, which spreads through close contact and was first found in monkeys, mostly occurs in West and Central Africa, and only very occasionally spreads elsewhere.

BLOOMBERG, REUTERS