Asthma does not appear to increase the risk for a person contracting Covid-19 or influence its severity, according to a team of researchers.

In a paper in the Journal of Allergy and Clinical Immunology, researchers attempted to answer important questions about asthma and Covid-19. It found also that the pandemic may have paradoxically improved some clinical outcomes of asthma management due to improved trigger remediation and medication adherence.

Reynold A. Panettieri Jr, a pulmonary critical care physician and director of the Rutgers Institute for Translational Medicine and Science, said: "Older age and conditions such as heart disease, high blood pressure, chronic obstructive pulmonary disease, diabetes and obesity are reported risk factors for the development and progression of Covid-19.

"However, people with asthma - even those with diminished lung function who are being treated to manage asthmatic inflammation - seem to be no worse affected by SARS-CoV-2 than a non-asthmatic person. There is limited data as to why this is the case - if it is physiological or a result of the treatment to manage the inflammation."

He said that since the news has focused our attention on the effects of Covid-19 on people in vulnerable populations, those with asthma may become hyper-vigilant about personal hygiene and social distancing. Social distancing could improve asthma control since people who are self-quarantined are also not as exposed to seasonal triggers that include allergens or respiratory viruses. There is also evidence that people are being more attentive to taking their asthma medication during the pandemic, which can contribute to overall health.

Inhaled steroids and Covid-19

The paper found that inhaled corticosteroids, which are commonly used to protect against asthma attacks, also may reduce the virus' ability to establish an infection. However, studies have shown that steroids may decrease the body's immune response and worsen the inflammatory response. Steroids also have been shown to delay the clearing of the SARS and MERS virus - similar to SARS-CoV-2 - from the respiratory tract and thus may worsen Covid-19 outcomes.

Future studies should address whether inhaled steroids in patients with asthma or allergies increase or decrease the risks of SARS-CoV-2 infection, and whether these effects are different depending on the steroid type.

Panettieri said that asthma tends to be associated with far fewer other conditions than chronic obstructive pulmonary disease or cardiovascular disease. If SARS-CoV-2 is a disease that causes dysfunction in the cells that line blood vessels throughout the body, then diabetes, heart disease, obesity and other diseases associated with this condition may make people more susceptible to the virus than those who are asthmatic.

However, older people with asthma who also have high blood pressure, diabetes or heart disease may have similar instances of Covid-19 as non-asthmatics with those conditions.