This new study detailed in the Journal of the American Medical Association (JAMA) on May 20, discovered that the angiotensin-converting enzyme 2 (ACE2), which grows in abundance as the individual grows, might be the reason that less than two percent of all individuals infected with SARS-CoV-2 - the virus that causes the COVID-19 disease - are children.

Researchers had suspected that COVID-19 susceptibility could be linked to the amount of gene expression of ACE2 seen in the nasal cavity, given that the enzyme acts as a receptor to allow the SARS-CoV-2 virus to pass into the body.

To investigate this potential link, researchers looked for a relationship between the two - the level of gene expression of ACE2 in the nose and COVID-19 infection - by taking nasal swabs from 305 people involved in an asthma study. Researchers hypothesized that the lower the levels of enzyme gene expression, the less likely it is a person will be infected by COVID-19.

Researchers said they chose to swab the nose because it is one of the first access points for SARS-CoV-2 to infect an individual.