How does monkeypox spread and what are the differences with covid-19?

Researchers have identified a number of cases of monkeypox in the United States and Europe in recent weeks, raising concern that the viral disease is becoming more transmissible.

Normally monkeypox is only found in West and Central Africa, rarely spreading outside of the continent, but cases have been reported or suspected in the United Kingdom, Portugal, Spain and the United States.

How is monkeypox transmitted?

The virus was first discovered in 1958 after two outbreaks of a pox-like disease in research monkeys. It was not until 1970 that the first case of monkeypox in humans was identified in the Democratic Republic of Congo and similar cases have been reported in neighbouring countries.

The transmission can occur when a person comes into contact with an animal, human and other contaminated material which contains the virus. It is thought that the virus can enter the body through areas of broken skin, the respiratory tract, or the mucous membranes found in the eyes, nose and mouth.

Transmission between humans happens primarily though respiratory droplets, which can be passed during interactions. Typically the droplets cannot travel more than a few feet, so it usually takes prolonged face-to-face contact for the virus to spread.

Less common, but still a possibility, is transmission by body fluid or lesion material. Monkeypox can also spread through contact with a lesion material, such as by sharing contaminated clothing.

How is the transmission different to covid-19?

As we know from the mask-wearing rules, social distancing requirements, and restrictions on the size of gatherings, covid-19 is primarily spread through respiratory transmission. Over the last two years the necessities of the pandemic response have governed much of how we are able to interact with people, but how does monkeypox compare?

The respiratory droplets that often transmit coronavirus are obviously very similar to the main source of the spread in monkeypox. However, given that there are so few recorded instances of monkeypox transmission outside of Africa, it is difficult to be sure how the virus is spread.

In the UK, the Health Security Agency warned that there may be a greater risk of sexual transmission, given that a lot of the recent cases were reportedly found in men who self-identified as gay, bisexual or men who have sex with men. Researchers are now doing genomic sequencing to establish whether these cases are isolated or connected.

“My working theory would be that there’s a lot of it about in west and central Africa, travel has resumed, and that’s why we are seeing more cases,” said Jimmy Whitworth, professor of international public health at the London School of Hygiene and Tropical Medicine.

But, for now, Whitworth is confident that the scale of monkeypox will be nowhere near that of coronavirus: “This isn’t going to cause a nationwide epidemic like covid-19 did, but it’s a serious outbreak of a serious disease – and we should take it seriously.”