Association of COVID-19 Vaccination with Risk of Medically-Attended Post-Acute Sequelae of COVID-19 During the Ancestral, Alpha, Delta, and Omicron Variant Eras [Note: Finds no protective effect of COVID19 vaccination against long covid]

“Results

During the observation period, 6.9% of patients experienced medically-attended and diagnosed PASC. A diagnosis of PASC was associated with older age, female sex, hospitalization for the initial infection, and an increased severity-weighted comorbidity index, and was inversely associated with infection during the Omicron period. No difference in the development of diagnosed PASC was observed between unvaccinated patients, those vaccinated with 2 doses of an mRNA vaccine, and those with >2 doses.

Conclusions

We found no association between vaccination status at time of infection and subsequent development of medically diagnosed PASC. Vaccine remains an important measure to prevent SARS-CoV-2 infection and severity. Further research is needed to identify effective measures to prevent and treat PASC.”