Despite Vaccination, Pollution Increases the Risk of Serious COVID-19

Exposure to air pollution, regardless of vaccination status, is associated with an increased risk of COVID-19 hospitalization, according to a letter to the editor published online in the American Journal of Respiratory and Critical Care Medicine.

Zhanghua Chen, Ph.D., of the Keck School of Medicine at the University of Southern California in Los Angeles, and colleagues studied the associations of long- and short-term exposure to nitrogen dioxide (NO2), fine particles (PM2.5), and ozone with COVID-19-related hospitalizations in a study involving 50,010 people with COVID-19 from July 1, 2021, to August 31, 2021.

The researchers discovered that 34.0 and 4.2 percent of subjects were fully and partially vaccinated before being diagnosed with COVID-19, respectively. Within 30 days of COVID-19 diagnosis, 6.1 percent were hospitalized for COVID-19-related reasons.

After controlling for confounders and air pollutants, vaccination significantly reduced the risk of hospitalization, with adjusted odds ratios of 0.46 and 0.16 for partially and completely vaccinated people, respectively, compared to unvaccinated people.

Exposure to PM2.5 and NO2 was associated with an increased risk of COVID-19-related hospitalization with and without adjustment for vaccination status (adjusted odds ratios for one standard deviation increase, 1.17 and 1.13 for one-month PM2.5 and NO2, respectively, and 1.25 and 1.19 for one-year PM2.5 and NO2, respectively, without adjustment for vaccination status); the odds ratios of hospitalizations associated with PM2.5 and NO2 were slightly increased with adjust

“While COVID-19 vaccines are effective at lowering the chance of hospitalization,” a coauthor stated in a statement. “People who are vaccinated and exposed to polluted air are nonetheless at increased risk for worse outcomes than vaccinated people who are not exposed to air pollution.”

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