Risk of Post-Acute Sequelae of SARS-CoV-2 Remains High Even with Vaccination During Omicron Era: Study

United States: A recent study published in the New England Journal of Medicine concluded that throughout the pandemic, the cumulative incidence of PASC during the first year after SARS-CoV-2 infection decreased whereas in the omicron era, the risk of post-acute sequelae of SARS-COV-2 infection remained substantial among vaccinated persons who had SARS-CoV-2 infection.

Post-acute sequelae of SARS-CoV-2 infection (PASC), commonly referred to as long COVID. It refers to a range of symptoms that persist for weeks or months after the acute phase of COVID-19 has resolved. Fatigue, tiredness, shortness of breath, cough, headache, joint pain etc are the common symptoms that are associated with SARS-CoV-2 infection. Considering this, Yan Xie, from the Division of Pharmacoepidemiology (Y.X.), Washington University, St.Louis, et.al conducted a study to evaluate the cumulative incidence of PASC during the first year after SARS-CoV-2 infection.

For this purpose, the research team used the records of the Department of Veterans Affairs from March 1, 2020, and January 31, 2022, to build a study population of 441,583 veterans who were infected with SARS-CoV-2 infection and 4,748,504 noninfected participants were used as a control group. After 1 year of SARS-CoV-2 infection, the cumulative incidence of PASC was estimated during the pre–delta, delta, and omicron eras of covid-19.

The study assessed 206,011 persons with no vaccination and SARS-CoV infection during the pre delta era, and 54,002 persons with no vaccination and SARS-CoV-2 infection during the Delta era. 84,943 persons with vaccination and SARS-CoV-2 infection were evaluated during the omicron era.

The findings revealed that:

• Unvaccinated persons infected with SARS-CoV-2, the cumulative incidence of PASC during the first year after infection was 10.42 events per 100 persons, in the pre-delta era, 9.51 events per 100 persons in the delta era, and 7.76 events per 100 persons in the omicron era.

• Among vaccinated persons, the cumulative incidence of PASC at 1 year was 5.34 events per 100 persons during the delta era and 3.50 events per 100 persons during the omicron era. Vaccinated persons had a lower cumulative incidence of PASC at 1 year than unvaccinated persons

• Decomposition analyses showed 5.23 fewer PASC events per 100 persons at 1 year during the omicron era than during the pre-delta and delta eras combined; 28.11% of the decrease was attributable to era-related effects (changes in the virus and other temporal effects), and 71.89%was attributable to vaccines.

“The researchers concluded that in the omricon era, the chances of infection by SARS-CoV-2 remained among vaccinated persons. The incidence of PASC during first year after DARS-CoV-2 infection decreased over the course of a pandemic”, researchers concluded.

Reference

Xie, Y., Choi, T., & Al-Aly, Z. (2024). Postacute Sequelae of SARS-CoV-2 Infection in the Pre-Delta, Delta, and Omicron Eras. The New England journal of medicine, 10.1056/NEJMoa2403211. Advance online publication. https://doi.org/10.1056/NEJMoa2403211