How long will I test positive for Covid? Total days symptoms last - what to do if you get a positive result

Covid infections are still rising in the UK and have reached their highest level in England for three months, figures show.

The rise in cases has been driven by the BA.5 Omicron subvariant, which is now the dominant Covid strain in the country, the UK Health Security Agency (UKHSA) has confirmed.

The variant was first identified in April this year and has proven to be more transmissible than previous forms of the virus.

However, high levels of coronavirus antibodies among the population – either from vaccination or previous infection – mean the number of people seriously ill or dying from the virus remain low.

BA.5 marks the latest strain in a run of variants to become dominant in the UK, with Alpha previously dominant in the winter of 2020, followed by Delta in summer 2021, Omicron in winter 2021 and most recently Omicron BA.2 in spring 2022.

Scientists have also recently discovered another Omicron variant called BA.2.75 - nicknamed ‘Centaurus’ - which is closely related to the BA.5 and BA.2 strains. At the moment it only accounts for only a small number of cases in the UK.

People are being urged to stay at home if they feel unwell, with experts saying you are now twice as likely to have Covid if you have any cold-like symptoms than any other type of virus.

If you do fall ill with Covid, this is how long you can expect symptoms to last and the latest guidance on self-isolation.

How long will I test positive for Covid?

It can take up to six days on average for someone who is infected with Covid to experience any symptoms, according to the World Health Organisation (WHO), but it is possible for symptoms to show from one to 14 days.

If you get a positive test result, it likely means that you had coronavirus when the test was taken and the time it takes to get a negative test will depend on how severe symptoms are.

Gavi, The Vaccine Alliance says it is possible to test positive Covid for weeks, but people are likely not to be contagious for very long, even after a positive result.

Studies suggest that PCR tests start to detect the virus around one to three days before symptoms start, which is when the viral load will be highest. After this point, the amount of virus in the body gradually declines until it can no longer be detected by PCR.

In general, asymptomatic people can test positive for one to two weeks, while those with mild-to moderate disease often continue to test positive for a week or more.

Less sensitive lateral flow tests need a higher viral load to record a positive result, which is why they often only identify people during their most infectious period, according to Gavi.

Most people will only test positive for Covid for one to two weeks, although one patient in the UK tested positive for 505 days before their death, making it the longest known coronavirus infection, UK researchers have said. The previous longest known infection is thought to have lasted 335 days.

Most people who contract the virus are able to clear the infection naturally, but the patient in question had a severely weakened immune system and multiple other health conditions.

They first started showing symptoms and tested positive in early 2020, and tested positive many times until dying in 2021.

Researchers from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust, who studied the virus from nine Covid patients in London, were interested in how the virus changes over time in immunocompromised individuals.

First author Dr Luke Blagdon Snell, of Guy’s and St Thomas’ NHS Foundation Trust, said: “New variants of SARS-CoV-2, the virus that causes Covid-19, have emerged throughout the pandemic.

“Some of these variants transmit more easily between people, cause more severe disease, or make the vaccines less effective.

“One theory is that these viral variants evolve in individuals whose immune systems are weakened from illness or medical treatments like chemotherapy, who can have persistent infection with SARS-CoV-2.

“We wanted to investigate which mutations arise, and if variants evolve, in these people with persistent infection.”

How many days will symptoms last?

Symptoms of Covid should generally start to clear within a few days and will last around five days on average.

The NHS recently added nine new symptoms to its official list to reflect the wider range of signs that could indicate infection.

Previously, only three official symptoms were listed with people warned a high temperature, a new continuous cough, or a loss or change to sense of smell or taste were the key signs of infection to look for.

The full list of symptoms now includes:

• a high temperature or shivering (chills) – a high temperature means you feel hot to touch on your chest or back (you do not need to measure your temperature)
• a new, continuous cough – this means coughing a lot for more than an hour, or 3 or more coughing episodes in 24 hours
• a loss or change to your sense of smell or taste
• shortness of breath
• feeling tired or exhausted
• an aching body
• a headache
• a sore throat
• a blocked or runny nose
• loss of appetite
• diarrhoea
• feeling sick or being sick

Dr Angelique Coetzee, a private practitioner and chair of South African Medical Association who first identified the Omicron variant, said patients tend to have “extremely mild symptoms”, but in some cases symptoms may be more severe.

She told the Daily Mail: "The symptoms presenting in those with Omicron are very, very mild compared with those we see with the far more dangerous Delta variant.

"Patients typically present with muscle pain, body aches, a headache and a bit of fatigue. And their symptoms don’t seem to get any worse than that.

“After about five days they clear up, and that’s it."

When do I need to self-isolate?

The legal requirement to self-isolate after a positive Covid test ended across the UK earlier this year, with the governments instead asking people to take “personal responsibility”.

In England, it is recommended that you follow NHS guidance if you feel unwell. The NHS says you should stay at home and avoid contact with other people if you:

• have any symptoms of Covid and have a high temperature, or you do not feel well enough to go to work or do your normal activities
• have tested positive for Covid

If you have Covid you can pass on the virus to other people for up to 10 days from when your infection starts, although many people will no longer be infectious to others after five days. Those who test positive are urged to avoid meeting people at higher risk from Covid for 10 days.

If you live in Scotland, the Scottish Government recommends following the advice on NHS Inform.

If you test positive, you should stay at home and avoid contact with other people for five days after the day you took your test, or from the day your symptoms started (whichever was earlier).

If you have not tested positive, you should try to stay home until you feel better.

In Wales, you should self-isolate and order a test if you display Covid symptoms and continue to self-isolate until you get your result.

If the test is negative you can leave isolation immediately, but if it is positive you should isolate for five full days and then take another test, plus another the following day.

If both are negative you can leave isolation. If either one is positive, you should continue isolating until you get two negative results in a row, or until day 10, whichever is sooner.

In Northern Ireland, people are advised to isolate immediately if they have Covid symptoms or have tested positive.

If you display Covid symptoms you should self-isolate, order a test and remain in isolation until you get your result. If the test is negative you can leave isolation immediately.

If it is positive, you should stay at home and avoid contact with people for five days after the day of the test, or from the day symptoms started - whichever was earlier.

As children tend to be less infectious than adults, this period is reduced to three days for children and young people under the age of 18.