(HealthDay News) — Regardless of vaccination status, exposure to air pollution is associated with an increased risk for COVID-19 hospitalization, according to a letter published in the American Journal of Respiratory and Critical Care Medicine.
Zhanghua Chen, PhD, from the Keck School of Medicine at the University of Southern California in Los Angeles, and colleagues conducted a study involving 50,010 individuals aged 12 years and older with COVID-19 from July 1, 2021, to Aug. 31, 2021, to examine the associations between COVID-19-related hospitalizations and long- and short-term exposure to nitrogen dioxide (NO2), fine particles (PM2.5), and ozone.
Before COVID-19 diagnosis, 34.0% of patients were fully vaccinated, and 4.2% were partially vaccinated. Overall, 6.1% of patients had a COVID-19-related hospitalization within 30 days after COVID-19 diagnosis.
Vaccination significantly reduced the risk for hospitalization. After adjustment for covariates and air pollutants, the odds ratio (OR) was 0.46 for partially vaccinated patients and 0.16 for fully vaccinated patients, compared with unvaccinated patients.
With and without adjustment for vaccination status, exposures to PM2.5 and NO2 were associated with an increased risk for COVID-19-related hospitalization. The adjusted ORs for 1 standard deviation increase were 1.17 and 1.13 for 1-month PM2.5 and NO2, respectively, and 1.25 and 1.19 for 1-year PM2.5 and NO2, respectively, without adjustment for vaccination status.
The ORs for hospitalizations associated with PM2.5 and NO2 increased slightly with adjustment for vaccination status.
“While COVID-19 vaccines are successful at reducing the risk of hospitalization, people who are vaccinated and exposed to polluted air are still at increased risk for worse outcomes than vaccinated people not exposed to air pollution,” a coauthor said in a statement.