Can Air Pollution Weaken the Effect of Your COVID-19 Vaccine? New Research Suggests So!

Results indicate that people exposed to higher levels of fine particulate matter (PM2.5), nitrogen dioxide (NO2), and blank carbon (BC) before the pandemic appeared to have lower antibody responses to COVID-19 vaccines, thus suggesting that air pollution harms our immune system as well.

The study was conducted based on data collected from 927 participants between the ages of 40 and 65. They filled in questionnaires and donated blood in the summer of 2020 — first after the initial lockdowns and then in the spring of 2021 after the COVID-19 immunisation programs were rolled out.

Based on the participants' addresses prior to the pandemic, the extent of air pollution they were exposed to was approximated.

The team showed that pre-pandemic exposure to PM2.5, NO2, and BC was associated with a 5-10% reduction in vaccine-induced spike antibodies in previously uninfected people. The decrease in antibodies was shown both for early IgM responses and late responses measured by IgG. IgM antibodies develop at an early stage of infection against SARS-CoV-2 whereas IgG antibodies develop against SARS-CoV-2 once the person has recovered from coronavirus.

The IgG response after the first dose peaked later in participants exposed to higher air pollution levels, and lower IgG levels persisted for several months after vaccination, the study's authors reported.

"Air pollution can induce chronic inflammation, which has been associated with a negative effect on vaccine efficacy," explained Carlota Dobaño, co-senior author of the study, together with Cathryn Tonne. "Our findings are consistent with evidence that persistent organic pollutants reduce vaccine responses in children," she added.

This study adds to the growing body of evidence on the adverse effects of air pollution, even at the relatively low levels observed in Western Europe. But a similar study might be long overdue in India — home to some of the most polluted cities in the world.

Meanwhile, future research will spotlight the role of long-term exposure to air pollution on hybrid immunity (infection plus vaccination). This will help scientists assess whether the reduction in antibody responses could lead to an increased risk of breakthrough infections.

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