Until now it has been observed that younger patients, especially children are only mildly affected by Covid-19. As the scientific community continues to try and understand this virus, understanding the variety and severity of the symptoms is a critical first step.
To date, the Korean medical community and the Korean Center for Disease Control and Prevention have performed the most comprehensive testing. Through these testings, it has been uncovered that 6.3% of infected individuals are children under the age of 19 years old. Furthermore, it has been reported that this population of infected patients only experience mild forms of symptoms. Brodin et al. has put forth various hypotheses to explain this observation.
Differences in immune systems
Young children and infants have a different immune system, in regards to composition and responsiveness than adults. They have not been exposed to various environmental factors that trigger the formation of antibodies to SARS-CoV2.
Competition
Young children can show multiple simultaneous viral species within their respiratory tract. These other viruses can act as limiting competitors to the Covid-19 virus. Furthermore, this hypothesis is supported by the fact that individuals that have constant and repeated exposure to the Covid-19 virus experience more severe symptoms and death – as seen in health care workers.
Medications taken by adults
Many adults are treated for hypertension with medications that are angiotensin converting enzyme 2 (ACE2) inhibitors, or angiotensin receptor blockers. This can lead to over expression of ACE2, leading to a possible entry point of Covid-19 into the human body.