How long do coronavirus symptoms take to show?

The new strain of coronavirus has spread rapidly across London and the south east of England

There is a second strain of the coronavirus now spreading throughout England, particularly in the south east and London, where regions have been put into a new tier 4 system in a bid to curb the rapid transmission.

The variant is now believed to be the dominant strain infecting people, and although it does not cause a different course of illness or more serious outcomes, Boris Johnson has said it is up to 70 per cent more transmissible than the first strain seen throughout most of 2020.

Peter Horby, chairman of New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), confirmed the new variant “does have a transmission advantage over other virus variants that are currently in the UK”. 

Government data from 22 December shows there are now around 36,000 new coronavirus cases per day and 222,000 in the last 7 days. This is an increase of 84,000 from the week to 15 December.

As numbers rise - and hospital admissions climb towards the peak seen in April - people will be wondering how they will know if they have Covid-19 and when they can expect to see symptoms developing.

How long do symptoms take to develop?

Towards the start of the pandemic in March, studies showed it was taking on average five days for people to start showing the symptoms of coronavirus. But is that still the case with the new variant that is being transmitted more rapidly?

The government still says on its advice page that “symptoms can take up to 10 days to appear from your last contact with the person who has tested positive for Covid-19”.  

And you can be infectious “from two days before” you develop symptoms.  

The World Health Organisation (WHO) gives a more specific timeline saying: “On average it takes 5–6 days from when someone is infected with the virus for symptoms to show, however it can take up to 14 days.” 

What are the symptoms to look out for?

Medical experts have said there is no reason to believe that this variant will cause different outcomes in terms of symptoms or how the illness progresses. Sir Patrick Vallance said this week there is “no evidence that the disease course is any different”.

So the symptoms to be aware of are the same as they were previously.  

The NHS says the three main symptoms are: a high temperature, a new continuous cough, and a loss or change to your sense of smell or taste. This means you’ve noticed you cannot smell or taste anything, or things smell or taste different to normal.  

“Most people with coronavirus have at least one of these symptoms,” it says. If you are taking a coronavirus test you must do so within the first 8 days of having symptoms.

WHO has a longer list of possible symptoms (although admits some are less common than others). It says the most common symptoms of Covid-19 are: fever, dry cough and tiredness.

The less common symptoms are: aches and pains, sore throat, diarrhoea, conjunctivitis, headaches, loss of taste or smell, a rash on your skin or discolouration of your fingers and toes.