COVID-19 increases the risk of asthma exacerbation – UK study (2020-21)

A UK prospective study (conducted in 2020-2021) including 2100 people with asthma (that had had a vaccine booster in the past) reported that getting a COVID-19 infection increased the risk of asthma exacerbation by:

• 5 fold for any asthma flare-up (adjusted OR 5.11 (4.19 to 6.24) for booster within 12 months and 5.60 (2.98 to 10.53) for booster over 12 months ago)
• 6 to 9 folds for severe asthma flare-ups (requiring OCS, ED visit or hospitalisation), depending on the time since the booster was received , although the difference in risk between under and over 12 months was not statistically significant: adjusted OR 6.59 (4.70 to 9.22) for booster within 12 months and 9.20 (3.56 to 23.78) for booster over 12 months ago
• these results were adjusted/controlled for asthma treatment level (severity) and history of past flare-ups, amongst other potential confounders.

This study indicates that having a COVID infection continues to increase the risk of asthma flare-up in people with asthma, independently of asthma severity and asthma exacerbation history.

While the results suggest that longer time since vaccination increases the risk of severe asthma exacerbation, the difference was not statistically significant (confidence intervals overlap) and this requires further investigation.