Omicron reduced the risk of protracted COVID-19
Scientists at King’s College London have found that the omicron strain is less likely to cause prolonged COVID-19 than the delta variant. The results of the study are published in the Lancet.
The experts analyzed 56,003 cases of the disease among adults in the UK who tested positive for coronavirus between December 20, 2021 and March 9, 2022, when Omicron was the dominant strain. The researchers compared these cases with 41,361 cases of coronavirus infection between June 1 and November 27, 2021, when the delta variant dominated.
In 4.4 percent of cases, infection with the omicron resulted in long-term COVID-19, compared with 10.8 percent of cases with the delta strain. However, the absolute number of people who survived long-term COVID-19 was higher during the omicron period. Overall, those who have contracted the Omicron strain are 20 to 50 percent less likely to have long-term symptoms of coronavirus infection than those who have had the delta strain. The risk depended on age and time elapsed since vaccination.
Protracted COVID-19 is defined as the onset of symptoms of infection four weeks or more after onset. These include fatigue, shortness of breath, loss of concentration, and joint pain.