Is Monkeypox Airborne? It's Not Quite As Simple As You Think

Never say never, but for now, it's mostly spreading through physical and sexual contact in the UK.
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Monkeypox cases are rising globally and health anxiety is understandably rife, among those concerned about how (and why) the illness is spreading.

Just this week, #MonkeypoxIsAirborne was trending on social media, with people urging others to wear face masks over fears the virus could be spreading in the air. Masks have undeniably mattered throughout the Covid pandemic, but is monkeypox similar in how it’s spread? The answer, for now, is no.

So far, most cases of monkeypox in the UK appear to be linked to sexual or very close contact with other people. The majority of cases are among gay, bisexual and other men who have sex with men, which is why these at risk groups are being offered a vaccine to protect against the virus.

The latest data from the UK Health Security Agency (UKHSA) from August 1 showed there are 2,672 confirmed and 87 highly probable monkeypox cases in the UK. Of these, 2,638 are in England, with London home to the highest number of cases by far.

People are understandably wary of airborne transmission. At the start of the pandemic, health bodies were reluctant to acknowledge that Covid-19 was airborne. However, it is now widely recognised to be, which is why mask wearing has been the most effective public health measure.

While experts agree monkeypox could be found to have some airborne transmission in future, evidence suggests it’s not how people are currently catching it.

Monkeypox is a rare virus often compared to smallpox, although it is significantly milder and less deadly. Endemic in some west and central African countries, it can cause a variety of symptoms including muscle aches, fever, chills, swollen lymph nodes, exhaustion and weakness, but most notably it triggers a rash (or lesions) across the skin.

The majority of people experience mild to moderate symptoms, however young children and immunocompromised individuals are at risk of severe disease.

In past incidences, the spread of monkeypox was considered to happen mostly through respiratory droplets during close and prolonged face-to-face contact, through direct contact with body fluids of an infected person, or through contact with contaminated objects, such as bedding or clothing.

The latest iteration of monkeypox seems to be spreading mainly through sex.

A recent study looking at 528 monkeypox cases between April 27 and June 24, 2022 found 98% of those infected were gay or bisexual men, and transmission was suspected to have occurred through sexual activity in 95% of the persons with infection.

Lead author of the study, Dr John Thornhill, a consultant physician in HIV and sexual health at Barts Health NHS Trust and a clinical senior lecturer at Queen Mary University of London, tells HuffPost UK: “I think [airborne transmission] is possible but it’s not the efficient mode of transmission at the moment.”

In the current outbreak outside of Africa and non-endemic countries, monkeypox is mainly spreading during sexual contact, confirms Dr Thornhill. But experts are cautious to disregard airborne transmission altogether.

“If you want to dig down and say: is it possible to transmit monkeypox through the air? It probably is, mainly through droplet transmission,” says Dr Thornhill.

“That’s different to just being in the room with somebody. That would involve someone sneezing and coughing, and you’d probably need to be up close and personal with that individual. Personally I wouldn’t be worried about contracting monkeypox through the air, but I wouldn’t definitely say it’s not possible.”

The UKHSA’s recent report also suggested the primary mode of transmission is through close or sexual contact, but did warn the virus has been detected in air and environmental samples in the hospital room of infected patients.

Studies are underway to analyse this more. One piece of research, which has not yet been peer-reviewed, looked at environmental contamination with monkeypox virus from infected patients admitted to isolation rooms in the UK.

Surface swabs of high-touch areas in isolation rooms, of healthcare workers’ personal protective equipment (PPE), and from air samples collected before and during bedding change were analysed to assess contamination levels.

Researchers identified “widespread surface contamination” (66 samples were positive out of 73 in total) and five out of 15 air samples taken were positive with the virus. Significantly, three of four air samples collected during a bed linen change in one patient’s room were positive.

There have been no confirmed instances of airborne transmission in the UK yet, but there have been some cases of household transmission.

“Historically there have been a very few cases where spread through the air may have been responsible for transmission,” says Paul Hunter, professor in medicine at the University of East Anglia.

“Within the current pandemic we can be pretty sure that airborne spread is not playing a major role in transmission as infection is still almost entirely restricted to MSM [men who have sex with men] who have had close/intimate contact with others who were infected. If airborne spread was important we would have seen much wider transmission outside of the primary risk group.”

Prof Hunter adds: “Estimates provided to WHO by several countries all put the R0 value of monkeypox outside of the MSM sexual network as being less than 1.0, strongly suggesting that monkeypox is not being spread by an airborne transmission pathway.”

Professor Thomas House, an expert in infectious disease modelling at the University of Manchester, has been keeping a close eye on monkeypox infection rates in the UK.

He tells HuffPost UK: “No two viruses have exactly the same transmission routes, so it’s quite reasonable to ask early on in a new outbreak what there is about these that we don’t understand.”

That said, he also believes it is “far too early” to suggest monkeypox is airborne.

“For Covid it became clear at a certain point that there were certain airborne protections that healthcare workers should arguably have had access to, so this kind of ‘campaign’ made sense,” he says. “But for monkeypox it is taking attention away from the fact that we need to be prioritising people most likely to be exposed due to sex for limited vaccination, treatment, case detection, etc.”

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“The fact it’s got this bad means there’s something going on that we don’t fully understand,” he adds.

While most cases have overwhelmingly been in men, 13 women in the UK have now caught the virus, although it’s not clear how.

For now, experts agree that targeting the demographics impacted most is the best strategy – gay and bisexual men are being encouraged to get the vaccine if they think they’re at risk – as is providing better resources for contact tracing.

“I think it’s scaremongering to say ‘be careful, you need to wear a mask’ or anything like that,” says Dr Thornhill. “Obviously if somebody [you knew] had monkeypox you’d take precautions... but for the general public it’s not something that should be of concern.”

If someone in your household or who you’ve had close contact with is diagnosed with monkeypox, it’s best to steer clear until they are better.

“The primary transmission pathway remains skin to skin contact during close personal and intimate contact,” says Prof Hunter.

For people who are caring for an infected individual, wearing a mask and gloves remains common sense. But wearing a mask while having close intimate contact will do “little if anything to reduce risk”, he adds.

“We shouldn’t shame people for taking precautions,” agrees Prof House. But for now, the consensus is that if we do want to prevent the spread of the virus, it’s about reducing physical contact with known cases.

How to prevent monkeypox, according to the NHS

– Wash your hands with soap and water regularly or use an alcohol-based hand sanitiser.

– Talk to sexual partners about their sexual health and any symptoms they may have.

– Be aware of the symptoms of monkeypox if you are sexually active, especially if you have new sexual partners.

– Take a break from sex and intimate contact if you have symptoms of monkeypox until you get seen by a doctor and told you are no longer at risk of passing it on.

– Don’t share towels or bedding with someone with the virus.

– Don’t have close contact (within one metre) with someone who may have the virus.