COVID-19 Vaccination Could Lower Risk of Developing Asthma

COVID- 19 vaccinations could reduce the risk of developing other inflammatory diseases of the airways, including asthma, hay fever, and chronic sinusitis, according to study findings conducted by researchers at Karolinska Institute. The study authors, who published their findings in The Journal of Allergy and Clinical Immunology, noted that the risk of asthma, sinusitis, and hay fever was lower in vaccinated individuals compared with healthy unvaccinated individuals.^1,2

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“Our results suggest that COVID-19 can trigger type-2 inflammation in the airways, but not in other organs,” Philip Curman, a physician and researcher at the department of medical epidemiology and biostatistics at Karolinska Institute in Sweden, said in the news release.²

Understanding COVID-19 and Type-2 Inflammatory Diseases

Severe asthma or a chronic lung disease is a risk factor for COVID-19, leading to greater sickness for a longer duration. Multiple studies indicate that having asthma does not increase the risk of getting COVID-19 or experiencing a severe case; however, like other respiratory illnesses (eg, flu or respiratory syncytial virus), COVID-19 could trigger asthmatic episodes. The CDC identifies moderate to severe asthma as a chronic lung disease that can increase an individual’s likelihood of becoming severely ill from COVID-19.³

The full impact of COVID-19 infection and vaccination on type-2 inflammatory diseases is not yet clear. Although viral infections are known to cause immune dysregulation, there is still a lack of research on how COVID-19 infection and vaccination specifically affect type-2 inflammatory diseases across different organ systems.¹

Does COVID-19 Vaccination Lower Inflammation in the Airways?

Researchers conducted a large-scale retrospective study using a US electronic health records database of over 118 million patients to examine the effects of COVID-19. A total of 3 matched cohorts were included: individuals with a COVID-19 infection (n = 973,794), those who received a COVID-19 vaccine (691,270), and a group of unexposed controls (n = 4,388,409). Using propensity-score matching, the researchers balanced demographic and clinical factors across the groups. Following, the study authors noted that they calculated hazard ratios for developing new cases of asthma, allergic rhinitis, chronic rhinosinusitis, atopic dermatitis, and eosinophilic esophagitis over a 3-month follow-up period.^1,2

The results demonstrated that individuals who had COVID-19 had a 66% higher risk of developing asthma, along with a 74% higher risk of chronic sinusitis and a 27% higher risk of developing hay fever compared with healthy individuals. However, regarding the risk of atopic eczema, eosinophilic esophagitis, and inflammation of the esophagus, no increased risks were displayed.^1,2

Differing from the initial results, the study authors noted that vaccination lowered the risk of asthma by 32% (0.678; 95% 0.636–0.722) compared with healthy unvaccinated individuals and slightly lowered the risk of chronic rhinosinusitis (0.799; 95% 0.752–0.850).^1,2

“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 said in the news release.²

REFERENCES

1. Olbrich H, Preuß S, Hernandez G, et al. COVID-19 infection raises respiratory type-2 inflammatory disease risk, whereas vaccination is protective. The Journal of Allergy and Clinical Immunology. July 25, 2025. Accessed august 27, 2025. doi.org/10.1016/j.jaci.2025.07.030

2. COVID-19 is linked to increased asthma risk – vaccine offers protection. EurekAlert! News release. August 14, 2025. Accessed August 27, 2025. https://www.eurekalert.org/news-releases/1094735

3. Asthma and Allergy Foundation of America. COVID-19 (Coronavirus Disease), Asthma, and Allergies. Accessed August 27, 2025. https://aafa.org/asthma/asthma-triggers-causes/respiratory-infections-flu-cold-asthma/covid-19-new-coronavirus/