The initial data suggest that infants make up a small fraction of people who have tested positive for COVID-19. A Centers for Disease Control and Prevention study released in April reported 398 infections in children under one year of age—roughly 0.3 percent of all U.S. cases at that time for which age was known. In addition, most of these cases appear mild in nature… The question is: Why?
One of the favored hypotheses focuses on how easily the new coronavirus can gain access to the body’s tissues. Infection occurs when particles of the virus, SARS-CoV-2, enter human cells through a receptor called ACE2… The thinking is that infant cells have only a few ACE2 receptors, whereas those of an elderly person might harbor thousands. With fewer available points of entry in a baby, it could be harder for the virus to break in.
Although some of the details still need to be teased out, it is clear that infants are uniquely resilient to COVID-19—a finding that could aid in treatment development efforts. Scientists have already identified drugs that block certain inflammatory pathways in the body, and several are in clinical trials in COVID-19 patients. Another possibility is that drugs that target the ACE2 receptor could be the key to a vaccine or treatment.