Postacute Sequelae of SARS-CoV-2 Infection in the Pre-Delta, Delta, and Omicron Eras

This study evaluated the cumulative incidence of postacute sequelae of SARS-CoV-2 infection (PASC or “long Covid”) across major pandemic periods pre-delta, delta, and omicron using data from over 441,000 veterans with Covid-19 and nearly 4.75 million matched controls. The authors found that although the incidence of PASC at one year declined over time from 10.42 events per 100 persons during the pre-delta era to 7.76 during omicron significant residual risk persisted even during the omicron era, especially among unvaccinated individuals. Vaccination sharply reduced this risk, with a 3.50 event rate per 100 vaccinated persons during omicron. Decomposition analysis showed that 72% of the reduction in PASC incidence was attributable to vaccines and 28% to temporal changes (e.g., viral evolution, health system improvements). The authors emphasize that while the burden of long Covid has declined, it remains clinically and epidemiologically substantial and warrants sustained prevention, mitigation, and care efforts

This study evaluated the cumulative incidence of postacute sequelae of SARS-CoV-2 infection (PASC or “long Covid”) across major pandemic periods pre-delta, delta, and omicron using data from over 441,000 veterans with Covid-19 and nearly 4.75 million matched controls. The authors found that although the incidence of PASC at one year declined over time from 10.42 events per 100 persons during the pre-delta era to 7.76 during omicron significant residual risk persisted even during the omicron era, especially among unvaccinated individuals. Vaccination sharply reduced this risk, with a 3.50 event rate per 100 vaccinated persons during omicron. Decomposition analysis showed that 72% of the reduction in PASC incidence was attributable to vaccines and 28% to temporal changes (e.g., viral evolution, health system improvements). The authors emphasize that while the burden of long Covid has declined, it remains clinically and epidemiologically substantial and warrants sustained prevention, mitigation, and care efforts