Ok I’m back—for starters , here’s your best and most up to date source for Corona info: https://www.cdc.gov/coronavirus/2019-ncov/index.html
Next, as far as it primarily affecting the 63+ crowd : the immune system in our bodies weaken as we age and a slower and lesser of an antibody response happens across the board . We still make antibodies that fight infection, they still do their job , but it’s not as quick and when we were younger and packs a little less punch .
The immune system itself doesn’t start to kick in until 3 months of age after birth and whatever immunity a newborn baby has, is whatever antibodies came from the mom by way of crossing the placenta while in utero.
As far as kids not being drastically affected—once the immune system does kick in at 3 months , it’s pretty darn good and fast at making antibodies but with all immune response in anyone , there has to be an initial sensitization stage where the cells that make antibodies get to know the virus or other antigens as we call things that are foreign to one’s body and will cause an immune response by way of antibodies or cellular response (natural killer cells, cytotoxic T-cells , macrophages , etc) from the types of white blood cells.
Kids get exposed to a whole lot of germs and while they do get sick, they also make a memory immune response which kicks in faster the next time they’re exposed to the same antigen and lasts for life.
As a lab tech , we see more influenza B and RSV (respiratory syncytial virus) affecting kids and right now in the US, corona testing all goes to the CDC—it’s not something that the regular hospital labs test for but we do collect and send the samples along.
For more insight on how the immune system works , have a visit with Armandoh and watch his immunology videos found here—they’re short 5-15 min , and I use his videos on all topics in my classroom to solidify whatever I’m teaching at any point in the semester : https://armandoh.org/subjects/