Since the start of the coronavirus pandemic, there’s a measurement that’s become ubiquitous in our lives: 2 metres, or more recently, 1.5m+. According to SAGE experts, this is the golden distance that should help you avoid infection. This measurement isn’t guesswork; it’s based on the idea that COVID-19 spreads when droplets – that is, saliva or mucus – are released into the air when an infected person coughs or sneezes.

In effect, the virus is a hitchhiker on these droplets, which fall on surfaces within 2 metres of the cougher or sneezer. This is why health officials have also been urging people to wash their hands regularly, as droplets can contaminate surfaces for significant periods of time.

However, the issue with the novel coronavirus is just that – it’s new. This means that many scientists and researchers aren’t entirely certain about how it spreads. One of the things we’re most unsure about is whether or not coronavirus is airborne. This could substantially change public health recommendations and how we stem the spread.

What does airborne mean exactly?

It seems obvious to assume that viruses spread through the air, as it could technically apply to the aforementioned droplets. However, when we talk about airborne transmission, we are actually referring to the medicalised definition. This suggests that the virus is no longer a passenger on a droplet, but instead, is literally part of the air we breathe. When a virus is airborne, it’s actually in an aerosol form, that is, a liquid or a solid suspended in a gas. In this case, the virus is the suspended solid and the air is the gas that carries it.

So, is coronavirus airborne?

The issue over whether coronavirus is airborne has proved controversial. However, new evidence is emerging that the virus can linger in the air. In July, more than 200 scientists signed an open letter cautioning that airborne transmission is “a real risk”, urging the WHO to update its guidance.

Equally, at the beginning of October, the USA’s CDC conceded that “COVID-19 can sometimes be spread by airborne transmission.” Meanwhile, in the UK, a Labour MP in the House of Commons stated that “We know…that the virus thrives on close human contact, especially where the air is stagnant and in conditions that are poorly ventilated. We know that the virus is airborne.”

Of course, this is alarming considering the public has been led to believe that social distancing was enough to keep them safe. In fact, it’s entirely possible coronavirus has been spreading in enclosed spaces with poor ventilation. According to the statement from the CDC, it’s possible coronavirus was spread when, “the infected person was breathing heavily, for example, while singing or exercising.”

How can we effectively protect ourselves?

As more new evidence emerges, it’s clear that we need to take a multi-pronged approach to protect against COVID-19. The experts still maintain that we need to keep washing our hands, keeping our distance, and use face coverings. However, there are other measures we can take; for instance, air filtration systems are an important second line of defence. If indeed airborne transmission is a significant vector, we need to take action.