A recent study conducted by statisticians of the U.K. Office for National Statistics (ONS) revealed the epidemiology of long COVID-19 following infection with the Omicron variant. The experts tried to examine various aspects of long COVID-19 and how the condition may arise with different SARS-CoV-2 variants.
The new statistical bulletin focuses on the risk of long COVID after an initial infection compatible with the Delta, Omicron BA.1, and Omicron BA.2 variants.
The analysis focuses on individuals who have not previously experienced a SARS-CoV-2 infection and compared double-vaccinated with triple-vaccinated individuals. Triple vaccination included third and booster doses. However, the analysis found that in triple vaccinated individuals, there was no statistically significant difference in the risk of long COVID among the considered variants.
Dr. Daniel Ayoubkhani, the ONS’s principal statistician and co-author of the analysis said that the statistical findings offered insight into the long COVID-19 risk with Omicron variants.
“We believe this is the first published evidence to date on the epidemiology of long COVID following infection with the Omicron variant, and there is now a need for further research into the possible biological mechanisms behind our findings,” Dr. Ayoubkhani said.
According to the experts, the double-vaccinated individuals with initial infections compatible with the Delta variant were 50.3% more likely to report long COVID symptoms than those who experienced COVID-19 with the Omicron BA.1 subvariant. Moreover, data also found that the risk of long COVID-19 in those whose infections were compatible with Omicron BA.1 and BA.2 was not quite the same.
For triple-vaccinated individuals, the odds of developing long COVID symptoms were 21.8% higher for Omicron BA.2 compared to Omicron BA.1.
“Among triple-vaccinated adults, we estimate that approximately 1 in 15 people first infected with the Omicron BA.1 variant will report long COVID symptoms four weeks after infection, rising to 1 in 12 people first infected with the Omicron BA.2 variant,” said Dr. Ayoubkhani said.
Dr. Ayoubkhani and co-author Dr. Matt Bosworth, senior research officer at ONS, note in the bulletin that their primary analysis considered reported long COVID symptoms of any severity.
Dr. Ayoubkhani also explained that the published research in the U.K. has demonstrated that recording of formal long COVID-19 diagnoses is low and variable between primary care practices. “Self-reported symptoms are therefore the only way at present to estimate the prevalence of long COVID in the population,” he added.
Dr. Koen Pouwels, senior researcher for Oxford Population Health, who collaborated with Drs. Ayoubkhani and Bosworth, informed that the analysis tracked long COVID symptoms from four to eight weeks after initial infection.