As the U.S. faces a summer surge of Covid-19 infections, a new study has examined the evolving risk of developing long Covid. The research indicates that while the probability of long Covid has decreased since the pandemic’s onset, it remains significant, particularly among unvaccinated individuals. According to a June analysis by the federal Agency for Healthcare Research and Quality, approximately 18 million American adults have experienced long Covid.
The study, published in the New England Journal of Medicine, utilized advanced machine learning techniques to analyze data from millions of medical records from the Department of Veterans Affairs. It tracked individuals who contracted Covid-19 at different stages of the pandemic — pre-vaccine, during the Delta variant’s prevalence, and following the emergence of the Omicron variants. It found that vaccination has notably reduced the risk of long Covid, especially during the Delta variant phase.
Despite vaccines cutting the risk by half during Delta’s surge, the risk remained elevated for those unvaccinated. During the Omicron phase, 3.5% of vaccinated people and 7.7% of unvaccinated individuals developed long Covid symptoms post-infection.
However, the study has limitations due to its predominantly white male veteran participants, which may not fully represent the general population’s diversity. It also does not account for the immunity provided by subsequent infections or the protective effects of booster vaccines as the virus evolved.
The financial and human toll of long Covid is significant, with economist David Cutler estimating a national cost of $3.7 trillion. The findings stress the importance of vaccination as a critical strategy to mitigate long Covid risks, according to Dr. Hector Bonilla of Stanford’s Post-Acute Covid-19 Syndrome Clinic.
As the virus continues to evolve, the study suggests that changes in the virus itself have contributed to a reduction in long Covid risks. Yet, despite progress, the condition remains a serious concern with substantial implications for public health. The ongoing need for coordinated care and accelerated research into treatments for long Covid underscores the urgency of addressing this public health issue comprehensively.
