Monkeypox Airborne Transmissions May Be From Rash Blister Fluids

Cases where monkeypox appears to have spread through airborne particles may have been caused by blister fluids suspended in the air, experts have said.

Before the most recent outbreak spreading throughout the globe, Monkeypox was usually only recorded in areas of western and central Africa.

In recent weeks however more than 1,000 cases have been recorded across 29 countries, according to Centers for Disease Control and Prevention (CDC) data.

It is believed that the main source of transmission is through direct, physical contact. However, in recent days the CDC has updated its guidance on the virus, advising those who contract it to wear a mask.

Face masks were helpful for preventing the spread of COVID-19 because the virus largely spread through airborne respiratory droplets. This means the virus can be spread to others nearby when an infected person sneezes or coughs.

The new guidance has led to many wondering: can monkeypox be airborne too?

Monkeypox rash
A picture shows monkeypox lesions on hands. Experts say that flakes and fluids from the blisters can become suspended in the air and infect others. Smith Collection/Gado/Getty

This question first came to the fray following a case from 2018, where a healthcare worker became infected with monkeypox while changing the bed of an infected patient. Many have suspected that airborne transmission was the only explanation for this case.

Those with monkeypox often develop a rash of lesions around the body. Professor Paul Hunter at the the U.K.'s Norwich School of Medicine, University of East Anglia, told Newsweek that the riskiest mode of transmission is to directly touch these blisters.

"As the scabs flake off into the bed they can be suspended in the air when changing the bed," he said.

Hunter believes this was what caused the case in 2018. However, he said the virus could also potentially spread through oral or respiratory fluids when there are lesions in the mouth.

"In COVID the virus in the air would primarily be generated by coughing, whereas for Monkeypox, [it's] probably from flaking skin or scabs as they are being scratched or rubbed off into bed linen or clothing, though some respiratory droplets may occur," he said.

However, there have so far been no cases amid the current outbreak that can be linked to airborne transmission.

"There is still a lot we don't know but the evidence is that the infection is primarily spreading between household or other intimate contacts and aerosol transmission is not an obvious transmission pathway at present," Hunter said.

Dr. Hugh Adler, an honorary research fellow at the Liverpool School of Tropical Medicine in the U.K. told Newsweek that "precise language is important" when discussing whether monkeypox can be spread through airborne aerosols and airborne respiratory droplets.

"Respiratory droplet transmission is very different to aerosol/airborne transmission. Monkeypox probably does transmit via large respiratory droplets, though it is likely that direct close contact with a patient, or their shed skin/bedding, is a more important driver of transmission," Adler said. "Large droplets travel about 1 meter (3 feet) in the air before falling to the ground. Tiny aerosols (airborne particles) from the lower respiratory tract remain in the air for longer—there is currently no evidence for monkeypox being transmitted via this route."

It also seems unlikely that the virus would mutate and become more airborne, Hunter said.

"Monkeypox has been increasing in Central and Western Africa for some years, partly as a result of waning immunity now that smallpox vaccination stopped some decades ago but mainly I suspect from degraded habitats and land use changes bringing people and especially children into closer contact with the reservoir animal species," Hunter said. "So as [the virus] increases in Africa the potential for visitors to those areas coming into contact either with an animal or with and infected individual has increased. If that person or persons then participate in activities where that have close/intimate contact with several others on their return then the risk of a super spreader event increases. So the current epidemic in Europe is probably down to random events."