Ask a doctor: How far do particles from a sneeze travel?

Covid-19 has had a severe impact on public health, so even when the day comes that we no longer have to wear surgical masks while out, you might still get a little uneasy if someone near you lets out a sneeze.

But just how far do the particles of a sneeze travel, and how easy is it to contract a respiratory illness-whether the coronavirus or the flu-from a sneeze?

The particles can reach you lightning-fast

As it turns out, there's a good reason for you to be nervous if someone around you sneezes without covering their mouth in some way.

"The current consensus is that particles from a sneeze can travel approximately one to two metres and float in the air for several seconds. Depending on the composition of the fluid and air movement, these values can increase," says Dr Matthew Tan, a resident doctor at DTAP Clinic.

He adds that put in perspective, if a person at arm's length sneezes in your direction, the aerosolised particles can land on you before you finish saying a sentence like "Happy Birthday".

It's also reasonable of you to worry about coming into contact with surfaces that these particles land on.

"Most viral particles have a half-life that ranges from one to three hours. This means it takes that amount of time for the total number of the particles to be reduced by 50 per cent."

He shares that, specifically for Covid-19, emerging research has found the half-life of its particles to be about one hour.

And that when it comes to the types of materials they thrive on, the most amount of virus has been found on plastic, followed by stainless steel, copper and cardboard.

Keeping a wide berth can make a big difference

We tend to blame the weather for being too hot or too rainy whenever a flu bug of sorts is going around. But it's not actually the weather that causes the rise in infections - it's the way in which we behave socially because of it.

"Bad weather tends to result in people huddling together to take shelter. Huddling puts us in closer proximity with one another, hence increasing the risk of people coming into contact with an infected person. This is why more people fall sick when the weather is bad," explains Dr Tan.

And not that you don't know this already, but it's really important that you maintain good hygiene habits and avoid touching your mouth, nose and eyes to protect yourself from a respiratory illness.

"Our mouth, nose and eyes are lined by tissue called mucosal surfaces, which create a good environment for our organs to function but is also a good landing pad for the virus to thrive. Washing our hands reduces the amount of virus on us, and not touching our faces further reduces the chances of us hosting a virus that can make us unwell."

In the unfortunate event that you do get sneezed on, he recommends immediately cleaning away any visible fluid and, if possible, changing into a new set of clothes.

There's a correct way to sneeze

Sick and don't happen to have a mask on while out and about? Considerate as you may want to be (though if you were, you should be staying home), you shouldn't try to hold a sneeze in.

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"Holding in a sneeze or cough can cause a buildup of pressure in the body. While there are no definitive studies to prove that these pressures can be harmful to you, several studies from hospitals around the world have reported a wide range of injuries from a holding in a sneeze. These include burst blood vessels and broken ribs."

Aside from sneezing into your hands, you can also practise the "correct" way of covering your nose to minimise the spread of particles.

"Sneezing or coughing into your elbow is a proven way to reduce the spray of respiratory fluid particles. It's also a good way to reduce the chances of you passing on your infected respiratory fluid to someone else when you come into contact with them."

In short, keeping your distance and practising good hygiene habits can significantly reduce your odds of contracting a virus. And if you have to sneeze, do so into your elbow.

For the latest updates on the coronavirus, visit here.

This article was first published in CLEO Singapore.