21st December, 20217 min read

Long COVID — what do we know so far?

Medical reviewer:Dr Ann Nainan
Author:Dr Roger Henderson
Last reviewed: 16/12/2021
Medically reviewed

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The coronavirus that causes COVID-19 has been spreading throughout the world since the end of 2019. During this time, we’ve learned a lot about the virus and the disease (although we learn more with each new variant that appears).

We know that the virus is spread by small droplets that are released when an infected person coughs, sneezes, talks or breathes, and that it can cause a wide variety of symptoms. The main symptoms can include a temperature (fever), a new cough, and a loss of your sense of smell or taste.

However, there are many other common symptoms, including tiredness (fatigue), achy muscles and shortness of breath. And the most commonly reported symptoms have changed over time, as we learn more, more people are vaccinated and new variants appear. Current evidence suggests that both the Delta and Omicron variants are more likely to cause cold-like symptoms, such as a runny nose, sore throat and headache.

What’s more, we now know that some people get ‘long COVID’. This is when someone who’s had COVID-19 continues to report lasting effects. Read on to learn more about long COVID, including the symptoms and possible treatment options, and when to see a doctor.

What is long COVID?

Many people with mild COVID-19 fully recover after about 2 or 3 weeks. But it’s now clear that this isn't the case for everyone. The term long COVID can refer to both ‘ongoing symptomatic COVID-19’ and ‘post-COVID‑19 syndrome’.

Ongoing symptomatic COVID-19 is when you still have signs and symptoms of the illness from 4 to 12 weeks after infection. Post-COVID-19 syndrome is where symptoms continue for more than 12 weeks, and can’t be explained by another diagnosis.

The latest figures suggest that about 1.2 million people in the UK – 1.9% of the population – have COVID-19 symptoms for more than 4 weeks after their infection with coronavirus.

What are the symptoms of long COVID?

Extreme tiredness (fatigue) is the most commonly reported symptom of long COVID. Other common symptoms include shortness of breath, loss of sense of smell and problems with memory or concentration – often known as ‘brain fog’.

However, there are many other possible symptoms linked to long COVID. These include a cough, low-grade fever, chest pain, headaches, muscle pain and weakness, tummy trouble (gastrointestinal upset), skin rashes and mental-health issues such as depression.

There is also some evidence to suggest that long COVID may cause a condition called postural orthostatic tachycardia syndrome (POTS), which causes your heart rate to speed up more than it should when you stand up. Symptoms can include dizziness, fainting, brain fog and fatigue.

What causes long COVID?

At the moment, it’s not understood why some people get long COVID and other people don’t.

It’s thought that it could be caused by various things. These include your body having an overactive immune response to the virus; ‘pockets’ of virus that stay in your body for a long time; and inflammation of small blood vessels in your body, along with abnormal blood clotting events.

Who’s affected by long COVID?

Only a small number of the people who get COVID-19 will go on to develop long COVID, but it’s possible for anyone who’s been infected to get it.

Getting long COVID is not thought to be linked to how ill you are when you’re first infected with COVID-19 (including whether you’re hospitalised with the illness). In fact, you can be diagnosed with long COVID without ever having tested positive for COVID-19, and you may have had no symptoms (been asymptomatic) when you were infected.

Because of this, it’s difficult to know who will develop long-term symptoms. But as a proportion of the UK population, long COVID symptoms are reported more by people who:

  • are female
  • are aged 35 to 69
  • have another health condition or disability
  • work in health or social care
  • live in deprived areas

When to see a doctor

If you still have COVID-19 symptoms after 4 weeks, see a doctor. Your symptoms may be part of your body’s response to the virus or they may be caused by something else, so it’s important to get help as soon as you can.

Depending on your symptoms, your doctor may refer you to a post-COVID clinic, a specialist with expertise for your specific problem, or a rehabilitation service.

You should also see a doctor if you get new symptoms or your symptoms are getting worse, or you’re concerned.

You should see a doctor straight away if you have any of the following symptoms:

  • chest pain
  • trouble breathing
  • losing weight
  • coughing up blood

What are the treatment options for long COVID?

Your doctor can help you manage long Covid by…

  1. – giving you information and providing access to support or treatment. Depending on your symptoms, they may also arrange tests – such as blood tests or a chest X-ray – to rule out other conditions.

  2. – referring you to a recovery programme if you have ongoing issues due to long COVID, your doctor may . This can be a face-to-face programme, or something you follow at home. Your symptoms will be assessed to work out what sort of programme would be best for you.

  3. – referring you to see a specialist for more investigations, for example for more tests to diagnose POTS or for more tests to rule out other causes of loss of smell.

There are things you can do yourself to manage long Covid

  1. If fatigue is a problem, make sure you rest regularly and plan your day so you can avoid getting overtired. If you can, ask other people for help, prioritise what’s important to you, and do your most important jobs when you have the most energy. Try to have a regular routine each day, and keep stress and anxiety as low as you can.

  2. If you’re struggling with a cough or breathlessness, practising breathing control or breathing techniques can help. You should ensure you drink plenty of water throughout the day, and take any medication you’ve been prescribed. Avoiding staying in one position for long periods can also help.

  3. If your sense of smell still hasn't come back after 2 weeks it's recommended you start smell training. You can find out more about this here.

  4. If you've been diagnosed with POTS, things that can help include drinking plenty of fluids, avoiding caffeine and alcohol and getting up slowly when you've been lying down. Read more about managing POTS.

You can get more advice on managing the symptoms of long COVID from online resources, such as the NHS website Your COVID Recovery and the SIGN Long COVID patient booklet.

Key points

  • most people who have COVID-19 recover within a few weeks, but some people get symptoms for weeks or months after infection
  • long COVID is when you have symptoms for 4 to 12 weeks (ongoing symptomatic COVID-19) or more than 12 weeks (post-COVID-19 syndrome)
  • symptoms of long COVID vary, but the most common include fatigue, shortness of breath, loss of smell and brain fog
  • long COVID doesn’t seem to be linked to how ill you are when you’re first infected
  • if you still have COVID-19 symptoms after 4 weeks, or you’re worried about your symptoms, see a doctor
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