There was a ‘dramatic’ decline in new incidence of the respiratory condition, according to a US study.
Childhood asthma halved in the first year of the pandemic, prompting questions about the role of infections in the development of the respiratory condition.
“We think this may have occurred in part because, earlier in the pandemic, children were separated, wearing masks and getting fewer regular colds that could trigger asthma,” lead author Assistant Professor Daniel Horton, a paediatrician and epidemiologist at Rutgers Institute for Health, Health Care Policy and Aging Research, said in a statement.
“No one wants to keep children out of school or separated, but having kids wear masks while they have a cold or the flu might be a way to keep other kids who are at risk for developing asthma a little safer.”
While there was a decline in asthma exacerbations and emergency visits among children during the pandemic, little was known about whether this period came with a changed rate in new diagnoses.
To understand whether the pandemic had any effect on the development of the condition, researchers analysed a US commercial claims database of children under 18. They found that in the first year of the pandemic, the incidence of asthma in these children dropped by 52% compared to the three years prior.
“These findings underscore a dramatic change in the incidence of asthma in the US during the early phases of the pandemic, complementing other literature on pandemic-related improvements in asthma control,” Professor Horton and colleagues wrote in Respiratory Research.
The authors suggested that improvements in asthma control may have been partly thanks to fewer respiratory viruses, such as rhinovirus, circulating due to covid-prevention measures including social distancing and mask wearing.
They pointed to previous Japanese research correlating the drop in asthma incidence to fewer cases of RSV and rhinovirus.
“Viruses such as rhinovirus are well-described triggers of childhood wheezing and subsequent diagnoses of asthma in children. Notably, young children with allergic sensitisation are more susceptible to rhinovirus-associated wheezing,” the authors wrote.
“Rhinovirus infection may also predispose some children to develop asthma, particularly in the presence of certain commensal respiratory microbiota, such as Moraxella, Haemophilus, and Streptococcus,” the authors wrote.
They speculated that the drop in air pollution over the pandemic may have also played a role in reducing asthma incidence.
