Y Xie, et al. NEJM 2024; DOI: 10.1056/NEJMoa2403211. Postacute Sequelae of SARS-CoV-2 Infection in the Pre-Delta, Delta, and Omicron Eras
Background: Postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PASC), also called “long Covid,” can affect many organ systems.1,2 The risk of PASC appears to increase with greater severity of infection and with the presence of preexisting medical conditions.
Methods: The authors used the health records of the Department of Veterans Affairs to build a study population of 441,583 veterans with SARS-CoV-2 infection between March 1, 2020, and January 31, 2022, and 4,748,504 noninfected contemporaneous controls.
Key findings:

NY Times, Pam Belluck 7/17/24: Vaccines Significantly Reduce the Risk of Long Covid, Study Finds
An excerpt:
The lowest rate of long Covid in the study, 3.5 percent, was among vaccinated people who were infected during the latest period in the study, between mid-December 2021 and January 2022. That compares with a rate of 7.8 percent for unvaccinated patients in the study who were infected during the same period…
To rule out other possible causes, the researchers factored in comparisons between uninfected people who developed similar symptoms…
Researchers found that among unvaccinated people infected between June 19 and Dec. 18, 2021, when Delta was the dominant variant, the rate of long Covid a year later decreased slightly to 9.5 percent from 10.4 percent among those infected in the first 15 months of the pandemic…
Among vaccinated people who had been infected, the rates of long Covid were markedly lower…About 5.3 percent of those infected during the Delta period had long Covid a year later, and 3.5 percent of those infected during the Omicron period did.
My take: A huge number of people in U.S. (and worldwide) have long COVID. This risk is markedly reduced with vaccination.
Related blog posts:
- Severe Cognitive Slowing Identified in Long COVID
- Long-Haul COVID: ‘Next Health Disaster’
- 30 Million Excess Deaths (Estimated) Worldwide due to COVID-19
- More Data Showing Increased Cardiovascular Risks with COVID-19 & Vaccination Reduces This Risk
- Why Are Immunization Levels Falling? It is not just due to COVID-19 and Anti-Vax Attitudes


