Vaccination against COVID-19 lowers the risk of developing long COVID symptoms, and this protective effect persists for up to 7 months following vaccination, as shown in a retrospective study.
In an analysis of electronic health record (EHR) data from a binary cohort of patients, the risk of long COVID over 12 months following acute infection among vaccinated patients was 16 percent lower than that observed among nonvaccinated patients (adjusted risk ratio [aRR], 0.84, 95 percent confidence interval [CI], 0.81–0.88). [EBioMedicine 2026;130:106382]
Additionally, vaccinated patients had a reduced risk of mortality compared with those who were unvaccinated (aRR, 0.83, 95 percent CI, 0.81–0.86).
“We did not find a significant relationship between COVID-19 vaccination timing, relative to acute COVID-19, and subsequent risk of long COVID in the first 7 months following vaccination,” reported lead researcher Prof Zachary Butzin-Dozier from the Stanford University School of Medicine, Stanford, California, US, and colleagues.
In a longitudinal cohort of patients who were vaccinated against COVID-19, the risk of developing long COVID did not differ between patients who contracted COVID-19 3–5 or 5–7 months after receiving their last COVID-19 vaccine/booster dose and those who contracted an infection 1–3 months after receiving their last COVID-19 vaccine/booster dose (aRR, 0.93, 95 percent CI, 0.62–1.41 and aRR, 1.06, 95 percent CI, 0.72–1.56).
Overall, “the findings provide critical evidence to inform public health strategies, clinical recommendations, and vaccination policies aimed at minimizing the long-term burden of COVID-19,” according to Butzin-Dozier and colleagues.
“Our study supports and extends prior evidence regarding the protective effect of COVID-19 vaccination against long COVID, emphasizing that vaccine-induced protection does not significantly diminish within 7 months after vaccination,” they added.
Butzin-Dozier and colleagues also pointed out that the mortality-lowering benefit associated with COVID-19 vaccination further underscores the potential of vaccines to limit long-term negative consequences of acute infection.
The next step in the research, they said, is to evaluate whether the effectiveness of SARS-CoV-2 vaccination, with respect to long COVID, wanes over time.
The binary cohort included 519,980 patients, of whom 55 percent had received two or more doses of COVID-19 vaccine prior to contracting infection. Compared with unvaccinated patients, those who were vaccinated tended to be older (>70 years: 16 percent vs 9 percent), have higher healthcare use (0.7 versus 0.5 visits per month) and a greater comorbidity burden, including lung disease (13 percent vs 10 percent), diabetes (13 percent vs 8 percent), and hypertension (28 percent vs 19 percent). A higher percentage of vaccinated vs unvaccinated were using systemic corticosteroid (29 percent vs 20 percent) and were immunocompromised (5 percent vs 3 percent).
The longitudinal cohort included 1,085,291 patients who were vaccinated against COVID-19. The timing of infection among patients who contracted COVID-19 infection during follow-up was 1–3 months after vaccination for 16 percent of patients, 3–5 months after vaccination for 21 percent, 5–7 months after vaccination for 22 percent, and more than 7 months after vaccination for 41 percent.