BACKGROUND: Individual case series and cohort studies have reported conflicting results on the vulnerability to and risk of mortality of people with asthma from COVID-19. RESEARCH QUESTION: Are people with asthma at a higher risk of being infected, hospitalised or of poorer clinical outcomes from COVID-19? METHODS: A systematic review and meta-analysis based on five main databases including the WHO COVID-19 database between December 1, 2019 to July 11, 2021 on studies with a control (non-asthma) group was conducted. Prevalence and risk ratios were pooled using Sidik-Jonkman random effects meta-analyses. FINDINGS: Fifty-one studies with an 8.08% (95% CI 6.87-9.30) pooled prevalence of people with asthma among COVID-19 positive cases. The risk ratios were 0.83 (95% CI 0.73-0.95, p=0.01) for acquiring COVID-19; 1.18 (95% CI 0.98-1.42, p=0.08) for hospitalisation; 1.21 (95% CI 0.97-1.51, p=0.09) for ICU admission; 1.06 (95% CI 0.82-1.36, p=0.65) for ventilator use and 0.94 (95% CI 0.76-1.17; p=0.58) for mortality for people with asthma. Subgroup analyses by continent revealed a significant difference in risk of acquiring COVID-19, ICU admission, ventilator use and death between the continents. INTERPRETATION: The risk of being infected with SARS-CoV-2 was reduced compared to the non-asthma group. No statistically significant differences in hospitalisation, ICU admission and ventilator use were found between groups. Subgroup analyses showed significant differences in outcomes from COVID-19 between America, Europe and Asia. Additional studies are required to confirm this risk profile, particularly in Africa and South America where few studies originate.
Adults (18+) Elderly (65+) Risk factor COVID-19