COVID-19 risk and effect modification by vaccination in asthma

We assessed COVID-19 infection, hospitalization and mortality in asthma patients and how vaccination modifies the risk. We included all Swedish residents on 1Jan2020. Asthma diagnoses from Jan2015-Dec2019 were identified from the National Patient Register (NPR). COVID-19 outcomes were: positive SARS-CoV-2 tests from national test data, hospitalizations from NPR, and deaths from the Cause-of-Death Register. Follow-up was from Jan2020 to Jun2023. Adjusted hazard ratios (aHR) and 95% confidence intervals (95%CI) were estimated using Cox regression for main effect models and for models with interaction between asthma status and COVID-19 vaccination doses. Of 10,333,978 individuals, 402,339 (3.4%) had asthma. In the asthma vs non-asthma group, frequencies of COVID-19 infection were 25.5% vs 24.2%, hospitalizations 3.1% vs 1.1%, and deaths 0.4% vs 0.2%. Compared to non-asthma, those with asthma had modestly increased risk of COVID-19 infection (aHR 1.06, 95%CI 1.06-1.07). aHRs for hospitalization were significantly elevated (2.00, 1.96-2.03). The aHR for COVID-19 death was low and non-significant except in the 40-64 age group (2.40, 2.02-2.84). The interaction analysis suggests similar relative vaccination protection across asthma and non-asthma groups (Fig). <bold>Conclusion:</bold> Asthma increases risk of COVID-19 hospitalization in all age groups and mortality risk in older adults. Vaccination confers similar risk-reduction in both asthma and non-asthma groups <fig><object-id>erj;64/suppl_68/OA5574/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>