Vaccines May Significantly Lower Long Covid Risk: Study

A large study recently published in the New England Journal of Medicine has provided some of the strongest evidence to date that vaccines significantly reduce the risk of developing long Covid. The study, which focused on people infected during the first two years of the pandemic, found a substantially lower percentage of long Covid cases among vaccinated individuals compared to their unvaccinated counterparts.

Medical experts have long suggested that vaccines can lower the risk of long Covid by preventing severe illness during the infection period. Individuals who experience severe infections are more likely to develop long-term symptoms. However, the study highlighted that even those with mild infections could develop long Covid, and vaccination, while significantly reducing the risk, did not entirely eliminate the possibility of developing the condition.

The study analysed medical records from the Department of Veterans Affairs health system, involving nearly 450,000 Covid-19 patients and approximately 4.7 million uninfected individuals from March 1, 2020, to January 31, 2022.

Researchers estimated the percentage of Covid-19 patients who experienced long Covid one year after infection. Among those vaccinated and infected during the latest period of the study (mid-December 2021 to January 2022), the rate of long Covid was 3.5 percent, compared to 7.8 percent for unvaccinated patients infected during the same period. This period included the emergence of the Delta and Omicron variants.

The results showed that the rate of long Covid among unvaccinated individuals infected between June 19 and December 18, 2021, during the Delta wave, was 9.5 percent. This rate decreased to 7.8 percent for those infected during the Omicron wave (December 19, 2021, to January 31, 2022). Among vaccinated individuals, the rates were significantly lower: 5.3 percent during the Delta period and 3.5 percent during the Omicron period. The researchers attributed about 72 percent of the decrease in long Covid cases to vaccination.

Although the study did not cover periods beyond January 2022, a recent survey by the Centers for Disease Control and Prevention (CDC) reported that about 5.3 percent of adults, or approximately 13.7 million people, currently have long Covid.