Omicron Variant Less Likely To Cause Long COVID
By KING'S COLLEGE LONDON
The SARS-CoV-2 Omicron variant is less likely to cause long COVID than the Delta variant, new research has found.
Analysis by researchers from King’s College London of data from
the ZOE COVID Symptom study app is published June 18, 2022 in a letter
to the medical journal The Lancet. The
findings are from the first peer-reviewed study to report on long COVID risk
and the Omicron variant.
Long COVID is defined by NICE guidelines as having new or ongoing
symptoms four weeks or more after the start of the 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.
Researchers found 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.
The study identified 56,003 UK adult cases first testing positive
between December 20, 2021, and March 9, 2022, when Omicron was the dominant
strain. Researchers compared these cases to 41,361 cases first testing positive
between June 1, 2021, and November 27, 2021, when the Delta variant was
dominant.
The analysis shows 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 number of people infected with Omicron from December 2021
to February 2022. The UK Office of National Statistics estimated the number of
people with long COVID actually increased from 1.3 million in January 2022 to 2
million as of May 1st, 2022.
Lead author, Dr. Claire Steves from King’s College London, said:
“The Omicron variant appears substantially less likely to cause Long-COVID than
previous variants but still 1 in 23 people who catch COVID-19 go on to have symptoms for more than four
weeks. Given the numbers of people affected it’s important that we
continue to support them at work, at home and within the NHS.”
Reference: “Risk of long COVID associated with delta versus
omicron variants of SARS-CoV-2” by Michela Antonelli, Joan Capdevila Pujol, Tim
D Spector, Sebastien Ourselin and Claire J Steves, 18 June 2022, The Lancet.
DOI:
10.1016/S0140-6736(22)00941-2
