Long COVID Incidence Declined Over Course of Pandemic

TUESDAY, July 23, 2024 (HealthDay News) -- The cumulative incidence of postacute sequelae of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection (PASC) during the first year after infection decreased over the course of the pandemic, according to a study published online July 17 in the New England Journal of Medicine.

Yan Xie, Ph.D., from the Veterans Affairs St. Louis Health Care System, and colleagues assessed whether risk and burden of PASC have changed over the course of the pandemic. Analysis included 441,583 veterans with SARS-CoV-2 infection between March 1, 2020, and Jan. 31, 2022, and 4.7 million noninfected controls.

The researchers found that among 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 one year was 5.34 events per 100 persons during the delta era and 3.50 events per 100 persons during the omicron era. Cumulative incidence of PASC at one year was lower among vaccinated versus unvaccinated persons (difference during the delta era, −4.18 events per 100 persons; difference during the omicron era, −4.26 events per 100 persons). At one year during the omicron era, there were 5.23 fewer PASC events per 100 persons than during the pre-delta and delta eras combined, of which 28.1 percent of the decrease was attributable to era-related effects (changes in the virus and other temporal effects), while 71.9 percent was attributable to vaccines.

"The cumulative incidence of PASC during the first year after SARS-CoV-2 infection decreased over the course of the pandemic, but the risk of PASC remained substantial even among vaccinated persons who had SARS-CoV-2 infection in the omicron era," the authors write.

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