For their study, Dr. Al-Aly’s team utilized databases within the VA to identify nearly 450,000 veterans who had been infected with SARS-CoV-2, as well as healthy controls. They divided this cohort into era-specific groups based on the SARS-CoV-2 variant: pre-Delta era (no vaccination), Delta era (no vaccination), Delta era (vaccinated), Omicron era (no vaccination), and Omicron era (vaccinated). They followed each group for a year to identify which one was most at risk for developing Long COVID symptoms. The researchers found that the rate of new Long COVID cases declined with each variant, and that the numbers of cases were significantly lower in the vaccinated cohorts.

https://www.yalemedicine.org/news/covid-vaccines-reduce-long-covid-risk-new-study-shows#:~:text=The bad news is%2C the,vaccinated people (primary series).

Interesting, considering there is a positive correlation between more vaccines and more immune escape. Perhaps this should have been included from the paper:

Conclusions

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. (Supported by the Department of Veterans Affairs.)