Am I Still Infectious? What People With Long Covid Symptoms Should Know

People are urged to self-isolate until their symptoms have cleared – but what if that's months down the line?

How long should people who are struggling with long-term symptoms of Covid-19 stay self-isolating? It’s a question that’s open to interpretation.

NHS guidance recommends people isolate for 10 days if they test positive for coronavirus. But if symptoms continue after this period – a high temperature or feeling hot and shivery; a runny nose or sneezing; feeling or being sick; or diarrhoea – the self-isolation period must continue.

“Only stop self-isolating when these symptoms have gone,” the guidance reads. Those with diarrhoea or sickness are urged to stay at home until 48 hours after such symptoms have stopped.

For some people with long Covid, symptoms may persist for (or return) months after first coming down with the illness. There are currently 30,000-40,000 new Covid-19 cases each day in the UK, with an estimated one in 10 people going on to develop long-term symptoms.

Self-isolating for this amount of time is a big ask. So up to what point are you still infectious and how long should you continue to self-isolate?

Andrey Zhuravlev via Getty Images

How long do you remain infectious?

Long Covid describes signs and symptoms that continue or develop after acute Covid-19 and includes both ongoing symptomatic Covid-19 (lasting from 4 to 12 weeks) and post-Covid-19 syndrome (lasting 12 weeks or more).

There’s no reason to think people with long Covid are infectious for longer just because they experience symptoms for longer, Professor Daniel Altmann, from the Department of Immunology and Inflammation at Imperial College, tells HuffPost UK.

A study published in the The Lancet Microbe suggests those infected with SARS-CoV-2 are most likely to be highly infectious a few days before their symptoms start and the five days after. This is why they are advised to self-isolate for 10 days.

Evidence suggests that RNA – or ribonucleic acid, which carries the genetic information of viruses – can be detected in Covid-19 cases between one and three days before symptoms appear. The highest viral loads are observed around the day symptoms start, according to the World Health Organisation (WHO), and then decline gradually over time.

Professor Paul Hunter, an expert in medicine at the University of East Anglia, points out that while people can shed virus for “quite some time” (sometimes for up to eight weeks, he notes), during this time the amount of virus declines.

Five to 10 days after being infected with SARS-CoV-2, an infected individual will usually begin to produce neutralising antibodies, and this should reduce the risk of virus transmission.

“Almost certainly people stop being infectious long before they stop shedding virus,” says Prof Hunter, “but it’s difficult to say for certain.” In other post-viral syndromes, symptoms often persist after viral clearance, he notes.

“I do not know if there is evidence that people with long Covid shed virus for longer,” he says, adding that it is still early days for the research. “Long Covid is almost certainly a lot of different conditions, some due to residual damage to organs such as long lung or neurological damage, others due to psychological factors, and a lot in between. Sometimes we are talking about several weeks [of symptoms] and sometimes we will be talking about several months/years.”

So, how long should you self-isolate?

Based on what we know, people should cease being infectious roughly 10 days after first developing Covid-19 symptoms – regardless of whether they go on to develop long-term symptoms of the virus or not.

“Whether or not people are going to go on to get long Covid, I think current advice is probably still sound,” says Prof Hunter, who says the NHS guidance to self-isolate for 10 days provides “a reasonable balance between controlling spread and not keeping people in isolation too long”.

A Department of Health and Social Care spokesperson tells HuffPost UK that for people who test positive for Covid-19, the 10 day self-isolation period begins from the day symptoms start, or the day of the test in asymptomatic individuals.

“If people are experiencing any of the symptoms recognised by Public Health England they should continue to self-isolate after the 10 day period,” they say.

“Meanwhile anyone who experiences new, ongoing or worsening symptoms more than four weeks after the start of symptoms or a positive test should discuss these with their GP.”

If a person is reinfected with Covid-19 – which can happen – they become infectious again and will need to self-isolate once more.