Why is the coronavirus mysteriously sparing kids and killing the elderly?

Why is it that COVID-19 manifests itself so drastically different between young children vs. the elderly? In China, 2.4 percent of reported cases were children and of these, 0.2 percent were chronically ill. In contrast, the fatality rate for those over 80 in China is particularly deadly, estimated at 21.9 percent, according to the WHO, based on over 44,000 confirmed cases. Moreover, fatalities and severe symptoms for children under the age of 10 are almost nonexistent.

The previous coronavirus outbreak, SARS in 2002 killed 774 people, but also spared the young. No children died from SARS in 2002. Similarly, few children developed symptoms from MERS coronavirus which has counted 858 fatalities since 2012.

A virologist from the University of Texas, Vineet Menachery stated that respiratory infections typically show a U-shaped curve with children on one end and older adults on the other, as the immunity of the former group isn’t fully developed and that of the latter group is weakened. However, the U-shaped curve does not apply to COVID-19.

While numerous questions have been explored as an explanation, research to date remains inconclusive. Frank Esper, a pediatric infectious disease specialist at Cleveland Children’s Clinic suggests the possibility that the answer may have “nothing to do with the virus and has to do with the host, like underlying conditions in the lungs, diabetes, or hypertension.”

Menachery and his lab have conducted experiments with mice, finding that baby mice ward off coronavirus infection, while the lungs of older mice become ravaged from the disease. Moreover, Menachery found that the cause of the older mice’s fatalities were related not only to compromised immune systems, but a “disregulation’ that caused their immune systems to overreact to the SARS coronavirus. That’s similar to how humans die of infections from (COVID-19).”

Interestingly, Esper ads, “I suspect there’s something more mechanical than immunological going on…Something about the receptors in children’s bodies or their lungs is interfering with the virus’ ability to attach itself.” This comment from Esper is particularly relevant to my recent research of the coronavirus and the relationship between the spike protein trimers and the host receptors of ACE2 located deep in the bronchii.

The article also states that while children show much milder symptoms of COVID-19, contact testing—testing people who come in contact with a confirmed case—shows that children are getting infected at similar rates as adults. Thus, children are potential drivers of infection, spreading the virus to parents, relatives, and the wider community. For this reason, closing schools could help protect adults and staff from the outbreak.

~~ Janette Canare