What does asymptomatic mean in terms of Covid-19?

It's just as dangerous as when you show symptoms.
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  • By definition we might know what ‘asymptomatic’ means, but in terms of Covid-19 and the impact of asymptomatic people, we might need to re-think.

    Over the last six months, as scientists have learnt more about coronavirus and how to works, the symptoms of Covid-19 in both adults and the symptoms of Covid-19 in children have become clearer. 

    But what about those people who aren’t diagnosed with the virus because they never get a test for coronavirus? With no evident symptoms, no coughs, fevers, shortness of breath or loss of appetite, people who are asymptomatic may think they are healthy and go about their days as normal. 

    But can they still pass on the virus? What does it mean for the wider spread of coronavirus around the world and in the UK? This is what is means to be asymptomatic in terms of Covid-19…

    What does asymptomatic mean in terms of Covid-19?

    To be asymptomatic means having coronavirus but not showing any symptoms at all. 

    Back in April, the Centres for Disease, Control and Prevention (CDC) in the USA released research that suggested asymptomatic carriers of Covid-19 may need to self-isolate to prevent spreading the virus. It was pointed out, however, that this relies on asymptomatic people being tested – something that’s unlikely to happen as the person won’t feel unwell, so won’t think there’s any need to book a test. 

    It’s one of the reasons that localised lockdowns in the UK and further national restrictions, such as the three tier system and circuit breaker lockdowns have had to be imposed.

    A woman wearing a face mask or covering due to the COVID-19 pandemic, sits on a bench close to a display showing health advice in the shopping district in central Sheffield

    More than a million people in northern England are banned from mixing with others under tougher new coronavirus rules. (Credit: Getty Images)

    Those that feel perfectly fine, without any symptoms, but actually have coronavirus are passing the virus on to those around them unknowingly. 

    Can asymptomatic patients transmit Covid-19?

    Recent research around asymptomatic coronavirus has concluded that it’s one of the ‘hidden drivers of the pandemic’. 

    The study also confirms that not only can asymptomatic patients transmit Covid-19, but it’s one of the most significant ways that coronavirus is spreading around the world.

    In fact the study, published in September, concluded that the frequency and highly infectious nature of asymptomatic people are the main reasons why Covid-19 turned from an epidemic (concentrated in one area) to a pandemic (a global spread). It also says that evidence points to the need for strict test and tracing systems of all known coronavirus contacts, regardless of symptoms, to prevent further spreading of the virus. 

    This means that if the NHS contract tracing app flashes up with a warning sign or those who’ve submitted their details are contacted by test and trace, it’s essential that they self-isolate.

    woman in clothes shop wearing a mask

    Credit: Getty

    It’s also why wearing masks in all indoor public spaces where social distancing can’t be maintained is essential. Coronavirus is spread through droplets in the air so by covering the mouth and nose with a mask, the infectious droplets are less likely to spread to others.

    How many people with coronavirus disease are asymptomatic?

    It’s currently not known how many people currently have coronavirus and are also asymptomatic, as despite calls for it to be included in the daily count of positive cases, this data is not currently recorded.

    However, a study from August this year in London suggests that anywhere from 20% to 27% of people with coronavirus are asymptomatic

    The research found that one out of every 5 people in London and the South East of England who have had coronavirus did not show any symptoms. It was also discovered that 27% of people who did feel unwell did not display the three main signs of coronavirus, which are a new and continuous cough, a fever and a loss of taste and smell. However, another study that was conducted in Italy back in July showed that over 40% of all coronavirus cases were asymptomatic. So there’s really no knowing how many people with coronavirus are asymptomatic. 

    Is there testing available for asymptomatic people?

    Currently, testing for coronavirus is only available for those who have symptoms. Even if an individual has been told they have come into contact with someone who has the virus, they are not supposed to go and get a test. This is because of the recent shortages in testing kits around the UK because people without symptoms, potentially also asymptomatic people, were getting tests as a precaution.

    As people with asymptomatic coronavirus don’t show symptoms by definition, the best way to ensure they don’t spread the virus onto someone else is to self-isolate at home when told to do so by test and trace or via the app.