Asthma attack rates in England fell significantly during the first COVID-19 pandemic lockdown of 2020, according to a study published in the journal Thorax.

Lower levels of air pollution, fewer cold and flu infections, and the fear of doctors’ offices were possible reasons for the 20% drop in cases seen at general practitioner surgeries, researchers said. The study includes data from more than 100,000 patients.

For the study researchers from the University of Edinburgh looked at a national database containing information on almost 10 million patients, and identified 100,165 who had had at least one asthma attack since 2016.

The team counted visits for asthma attacks in weekly blocks from January to August 2020, and compared with weekly rates for January to August 2016-2019. They used March 23 as the lockdown start date.

Drops in health care provider visits for asthma attacks during the lockdown were seen across all age groups, for both men and women, and across all regions of England excluding London and the North East. There was no reduction in the rate of asthma attacks that led to a hospital visit, suggesting that only milder attacks were reduced during the pandemic.

The researchers caution that some patients could have gone to hospital without a referral, which may mask higher rates of asthma attacks than recorded.

The study was conducted in association with BREATHE – The Health Data Research Hub for Respiratory Health, NIHR and the Asthma UK Centre for Applied Research.