COVID-19 Linked to Higher Risk of Asthma and Sinusitis: Study Finds - Video

A recent study published in The Journal of Allergy and Clinical Immunology reveals that individuals who have had COVID-19 face an increased risk of developing certain inflammatory airway diseases, including asthma, hay fever, and chronic sinusitis. The comprehensive epidemiological research, led by scientists at Karolinska Institutet, also highlights that vaccination against the SARS-CoV-2 virus appears to reduce this risk.

The international team utilized data from the TriNetX electronic health database in the United States to explore the association between COVID-19 and type-2 inflammatory diseases—a group of chronic conditions characterized by an overactive immune response to allergens or infections. The study compared three groups: 973,794 individuals who had contracted COVID-19, 691,270 people who had been vaccinated against SARS-CoV-2, and 4,388,409 healthy controls without documented infection or vaccination.

Results showed that people who had experienced COVID-19 had a 66 percent higher risk of developing asthma, a 74 percent higher risk of chronic sinusitis, and a 27 percent higher risk of hay fever compared with healthy controls. However, the study found no increased risk for atopic eczema, a skin condition, or eosinophilic oesophagitis, an inflammation of the esophagus.

Vaccinated individuals demonstrated a contrasting pattern, with a 32 percent lower risk of asthma compared to healthy unvaccinated individuals. Risks of sinusitis and hay fever were also slightly reduced among the vaccinated group. The difference was even more pronounced when comparing those who had COVID-19 with vaccinated individuals—those infected had more than twice the risk of developing asthma or chronic sinusitis, and a 40 percent higher risk of hay fever.

“Our results suggest that COVID-19 can trigger type-2 inflammation in the airways, but not in other organs,” explained Philip Curman, the lead researcher and physician at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet. “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,” Curman noted.

The study is retrospective, relying on previously collected data, which means causal relationships cannot be definitively established. Additionally, some infections may have gone undiagnosed, particularly those detected through self-testing. Despite these limitations, the findings underscore the potential benefits of vaccination beyond preventing COVID-19 infection, highlighting its role in reducing certain respiratory inflammatory conditions.

Reference: “COVID-19 infection raises respiratory type-2 inflammatory disease risk, whereas vaccination is protective”, Henning Olbrich, Sophie L Preuß, Khalaf Kridin, Gema Hernandez, Diamant Thaçi, Ralf J Ludwig, Philip Curman, The Journal of Allergy and Clinical Immunology, online 12 August 2025, doi: 10.1016/j.jaci.2025.07.030.