Risks of long COVID symptoms and the incidence of new onset hypertension, diabetes, and heart disease were lower among vaccinated patients with breakthrough infection versus those with COVID who were unvaccinated, a large analysis of medical records in the U.S. suggested.
Compared to those who were unvaccinated, relative risks were 0.33 for hypertension (95% CI 0.26-0.42), 0.28 for diabetes (95% CI 0.20-0.38), and 0.35 for heart disease (95% CI 0.29-0.44) at 90 days following COVID diagnosis for the vaccinated group, reported Grace McComsey, MD, of Case Western Reserve University in Cleveland, Ohio, and colleagues.
Moreover, risk of death 90 days later was significantly lower as well (RR 0.21, 95% CI 0.16-0.27), the authors wrote in Open Forum Infectious Diseases.
“Differences in both 28 and 90-day risk between the vaccine and no-vaccine cohorts were observed for each outcome and there was enough evidence … to suggest that these differences were attributed to the vaccine,” they wrote.
McComsey and colleagues examined retrospective data from TriNetX, described as “a large national health research network” from 57 U.S. centers. Participants were adults with SARS-CoV-2, confirmed by PCR testing, who sought care from September 2020 to December 2021. They were stratified into two groups: vaccinated with breakthrough infection and unvaccinated patients. Long COVID, or “post-acute sequelae of COVID” was defined as new, continuing, or recurrent symptoms occurring 4 or more weeks after initial COVID infection. Patients were also matched by baseline comorbidities.
Overall, 1,578,719 patients with confirmed COVID were identified, with 25,225 of those (1.6%) having documented COVID vaccination. In the vaccine cohort, average age was about 55, about 60% were women, and 68% were white. At baseline, 47% had hypertension, 23% had diabetes, and 13% had chronic kidney disease. In the unvaccinated cohort, average age was 43 years, 56% were women, and 62% were white. A lower proportion also had pre-existing conditions (28% with hypertension, 14% with diabetes, and 6% with chronic kidney disease), but none of these differences were significant after matching.
At 90 days following COVID diagnosis, the authors found risk of new or persistent outcomes was lower in the vaccine cohort versus the unvaccinated cohort. Incidences (per 1,000) in the vaccinated compared to the unvaccinated cohort, respectively, were 7.19 versus 20.26 for heart disease, 6.45 versus 25.53 for mental disorders, 6.42 versus 19.59 for hypertension, and 2.69 versus 9.69 for diabetes.
The vaccinated cohort also saw lower risks of new respiratory symptoms (RR 0.54, 95% CI 0.50-0.57), headache (RR 0.39, 95% CI 0.34-0.45), fatigue (RR 0.48, 95% CI 0.43-0.52), body ache (RR 0.34, 95% CI 0.28-0.42), and diarrhea or constipation (RR 0.44, 95% CI 0.40-0.49) at 90 days.
The authors noted that in addition to the usual post-COVID symptoms, such as headaches, fatigue, body aches, and respiratory and gastrointestinal symptoms, they found that vaccination was associated with a lower risk of new-onset diseases such as hypertension, diabetes, heart disease, and mental disorders. They “very carefully captured new outcomes” occurring after COVID, not merely pre-existing medical conditions, the group maintained.
“We hypothesize that [vaccination’s] effect on reducing the inflammatory responses during the acute phase does also explain the lower rates of all [post-acute sequelae of SARS-CoV-2] outcomes observed in our study among the vaccinated group,” wrote McComsey and coauthors.
Limitations to the data include use of electronic medical records, that true prevalence of these post-COVID symptoms is unknown, as many asymptomatic patients were not tested for the virus, and that immunization status may be a source of bias, as those who were likely to be vaccinated may have been more likely to seek or receive medical attention.
This study was supported by the Clinical and Translational Science Collaborative of Cleveland from the National Center for Advancing Translational Sciences component of the NIH and NIH Roadmap for Medical Research.
Zisis disclosed no conflicts of interest.
McComsey disclosed support from Tetraphase, Roche, Vanda, Astellas, and Genentech, Gilead, Merck, ViiV/GSK, Theratechnologies, and Janssen.