Updated 6th October 2022

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What’s your risk of Long COVID now?

Written byZOE Editorial Staff

    In the first peer-reviewed study to report on Long COVID risk and the Omicron variant, our team of researchers at King’s College London investigated the risk of Long COVID after infection. Using your reports from the ZOE Health Study, they compared data from the Omicron variant with what they’ve already discovered on the Delta variant. Their findings were published in a letter to The Lancet.

    Thanks to your daily health logs and test reports, we’ve been able to make this groundbreaking scientific discovery, continuing to pioneer crucial health research through your app-based community reporting.

    What is Long COVID?

    Long COVID is defined by NICE guidelines as having new or ongoing symptoms four weeks or more after the start of disease. Symptoms include fatigue, shortness of breath, loss of concentration and joint pain. The symptoms can adversely affect day-to-day activities, and in some cases can be severely limiting.

    What are the different types of Long COVID?

    Recent analysis conducted by our colleagues at King's College London, using data from the ZOE Health Study app found that there were three distinct types of Long COVID being reported by people, based on the type of symptoms they were experiencing.

    The largest group of Long COVID sufferers reported clusters of neurological symptoms such as fatigue, brain-fog and headache, and was the most commonly found among Alpha and Delta variants.

    A second group experienced respiratory symptoms including chest pain and severe shortness of breath, which could point to lung damage related to the infection. This was the largest cluster during the start of the pandemic before anyone was vaccinated.

    Finally there was a final smaller group with people who experienced  a diverse range of symptoms including heart palpitations, muscle ache and pain, and changes in skin and hair.

    This research was only conducted on those who had experienced the Alpha and Delta variants of COVID, so our team are still researching the distinct characteristics of Long COVID in Omicron cases.

    What’s your risk of Long COVID with Omicron compared to Delta?

    Our researchers found that the odds of experiencing Long COVID were between 20-50% less during the Omicron period versus the Delta period, depending on age and time since vaccination.

    We identified 56,003 UK adult cases in the ZOE Health Study app first testing positive between December 20 2021 and March 9 2022, when Omicron was the dominant strain. Our team compared these cases to 41,361 cases first testing positive between June 1 2021 and November 27 2021 when the Delta variant was dominant.

    In order to assess the association between long COVID and the infection period, our researchers adjusted by sex, IMD (Index of Multiple Deprivation), age, the presence of comorbidities, vaccination status (one, two, or three doses), and body-mass index, all of which are related to the risk of Long COVID. 

    We also looked at the time between infection and most recent vaccination considering three groups, 3 months, 3–6 months, and more than 6 months to allow for potential waning of immunity from vaccination.

    How many people experienced Long COVID?

    The analysis shows that 4.4% of Omicron cases were Long COVID, compared to 10.8% of Delta cases. However, the absolute number of people experiencing Long COVID was in fact higher in the Omicron period. This was because of the vast numbers of people infected with Omicron from December 2021 to February 2022. 

    The UK Office of National Statistics estimated the numbers of people with Long COVID actually increased from 1.3 million in January 2022 to 2 million as of 1st May 2022.

    What does this mean for the future?

    Dr Claire Steves from King’s College London who was the lead author of the letter says: ‘The Omicron variant appears substantially less likely to cause Long-COVID than previous variants but still 1 in 25 people who catch COVID-19 go on to have symptoms for more than four weeks.  Given the numbers of people affected it is important that we continue to support them at work, at home and within the NHS.’

    This study shows that with the ZOE Health Study community, we're able to produce accurate and fast insights based on your data that help advance our understanding of conditions like Long COVID.

    With the app, we were able to look at a broad range of symptoms in our Contributors as well as how frequently they occurred, and for how long. We were able to compare samples from both the Delta and Omicron periods as we had data for both of a similar scale. 

    What can I do to keep myself safe?

    There is an increased risk of developing COVID when more of the virus is present in the population.

    In order to lower your risk, the best thing to do is to minimise your chances of infection. This means wearing a good quality FFP2 or FFP3 mask in crowded or poorly ventilated areas, avoiding meeting up with anyone who may be showing symptoms, and practising good hygiene by washing your hands and avoiding touching your nose and mouth.

    Your daily reports are crucial for us to continue keeping track of both COVID infections and Long COVID, as well as any other symptoms and illnesses you may be experiencing on a daily or one-off basis. Your Usual Self feature in the app makes reporting any new symptoms much faster and easier, as well as helping to provide an early warning signal for multiple health conditions in the future.

    Help science and keep logging!