Even if You’ve Had a Covid Vaccine, Smoggy Air Could Make It Worse

No matter if a person is immunized or not, exposure to air pollution can hinder COVID-19 recovery.

According to study co-author Anny Xiang, a senior research scientist at Kaiser Permanente Southern California, “these findings are important because they show that, 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.”

Patient’s medical records from the Kaiser Permanente Southern California health system were examined by researchers. This comprised around 50,000 patients aged 12 and older who were identified as having COVID-19 in July or August 2021, when the Delta variant was in its early stages of spread. Approximately 34% of people had received all recommended vaccinations.

Researchers from the Keck School of Medicine at the University of Southern California were a part of the team. They calculated the patients’ exposure to ozone (O3), nitrogen dioxide (NO2), and PM2.5 one month and a year before to the diagnosis of COVID using street addresses and air quality data.

The researchers found that exposure to two of those pollutants, PM2.5 and nitrogen dioxide, increased the chance of hospitalization by up to 30% even among those who had received vaccinations. This was after they had established that vaccinations had an impact on hospitalization risk.

Co-author Zhanghua Chen, an assistant professor of population and public health sciences at Keck, stated that the probability of COVID hospitalization was reduced by about 90% in fully immunized individuals and by around 50% in partially immunized individuals.

Pollutant exposure was nevertheless damaging.

According to Chen, who was quoted in a USC news release, “the harmful effect of air pollution exposure is a little reduced among vaccinated people, compared to people who were not vaccinated.” The difference, however, is not statistically significant.

The study found that short-term exposure may affect the immune response and exacerbate pulmonary inflammation. Heart and lung conditions, as well as more severe COVID symptoms, are all connected to prolonged exposure.

High short-term PM2.5 exposure increased the probability of COVID-19 hospitalizations by 13% in the almost 31,000 research participants who were not immunized. There was a 24% risk increase with prolonged exposure.

With short- and long-term exposure to nitrogen dioxide, the risks rose by 14% and 22%, respectively. The investigation did not discover any correlating links between COVID hospitalizations and ozone levels.

The American Journal of Respiratory and Critical Care Medicine has published the findings.

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