How long do I need to be exposed to get COVID-19?

Another common question that seems to be asked around COVID-19 and the pandemic is just how long a person needs to be exposed to an infected person for the virus to be transmitted? We know all about the 2-metre social distancing rule and the need to wear face masks, but what about the time in relation to exposure?

AuthorityExposure Rule
Public Health EnglandWithin 2 metres of an infected person for at least 15 minutes
World Health OrganisationWithin 1 metre of an infected person for at least 15 minutes
European Centre for Disease Prevention & ControlWithin 2 metres of an infected person for at least 15 minutes
Centers for Disease Control & PreventionWithin 6 feet (1.82m) of an infected person for at least 15 minutes
British Medical Journal‘Have found evidence to suggest that being exposed to COVID-19 for less than 15 minutes has a significantly lower risk than being exposed for more than 15 minutes’
Oxford University‘We estimate that any definition where close contact requires more than 4 hours of contact is likely to lead to uncontrolled spread’

As we can see, most of the world’s leading authorities agree on both the 2-metre social distancing rule and the 15 minute rule for a ‘safe’ time of exposure. COVID-19 is transmitted through droplets from the nose or mouth – through a person talking or coughing near another person. So, the virus is spread through close contact. But as well as this close contact, the risk of contracting the virus is higher when that contact is sustained.

A person will typically start showing symptoms within five days of the initial exposure to the virus, but an infected person may still be contagious before starting to experience any symptoms.

And of course, we know that some people don’t even show symptoms (known as asymptomatic), but are still able to infect others. According to emerging research at the Harvard Medical School, ‘people may actually be most likely to spread the virus to others during the 48 hours before they start to experience symptoms’.

This 15-minute window doesn’t guarantee immunity, as a person could be infected within a few minutes of coming into contact with the virus. The 15-minute threshold that most countries have officially adopted is a combination of both science and practice. Leading organisations, such as the British Medical Journal, have found evidence to suggest that being exposed to COVID-19 for less than 15 minutes has a significantly lower risk than being exposed for more than 15 minutes. And so, this threshold has been used in practice to make the rules and guidance a bit easier for all of us.

However, this 15-minute threshold has to be in accordance with the 2-metre social distancing rule and wearing a face mask, or the probability of transmission shoots up.

Social distancing and face masks are the main ways a person can limit their exposure to COVID-19. Yet, these are not always possible to enact in reality – especially in indoor settings.

This is where air sterilisers come in. These are devices that use a technology which creates UV light, ozone, and negatively-charged ions.  These all exist in the environment already, so are safe, and are quite powerful methods of disinfection. They eliminate bacteria, viruses, mould, and can break down unwanted chemicals and smells.

Having an air steriliser in your workplace or on your premises can really help in reducing the likelihood and risk of COVID-19 being present.

You can find out more about air sterilisers and how they work in our guide we put out recently.


Just to note: The fixed installation air sterilisers we currently sell on our website are only recommended for washrooms or other transient areas where people only spend a short period at a time.

Air sterilisers are great additions to spaces that may need that extra bit of cleaning, like your washrooms. They’re easy to install and use, provide 24/7 cleaning support, reduce waste, and could save you on costs in the long-term.

For more information or for help in finding your ideal washroom product, please contact us on 0114 3540047, use our contact us page by clicking here or click to visit the website.

In the trade? Don’t forget we can set you up with a trade account for your purchases.

We have wholesaler, contractor, public sector and charity discounts available, please don’t hesitate to ask or find out more information by clicking here.

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