“Our results suggest that COVID-19 can trigger type-2 inflammation in the airways, but not in other organs. It is interesting to see that vaccination not only protects against the infection itself, but also appears to provide good protection against certain respiratory complications,” lead author of the study, Philip Curman, a physician and researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet, Sweden, said in a press release.
For the study, researchers compared electronic health records from 973, 794 people who had been infected with COVID-19, 691, 270 people who had been vaccinated against COVID-19, and 4, 388, 409 healthy controls who had neither been infected with COVID-19 nor been vaccinated.
Ultimately, they found that those who had COVID-19 were 66% more likely to develop asthma, 74% more likely to develop chronic sinusitis, and 27% more likely to develop hay fever than healthy controls. They also found, however, that those who had been vaccinated against COVID-19 were 32% less likely than healthy unvaccinated individuals to develop asthma. They also had a slightly lower risk of sinusitis and hay fever.
Further analyses showed that those infected with COVID-19 were 2-3 times more likely than vaccinated individuals to develop respiratory type-2 inflammatory diseases. The findings suggest that being vaccinated against COVID-19 may reduce respiratory complications from type-2 inflammation, thus reducing disease burden, wrote the researchers in their study.
The study's retrospective nature means that researchers cannot draw firm conclusions about causal links.
Sources: The Journal of Allergy and Clinical Immunology, EurekAlert
