The coronavirus pandemic has hit older people far harder than those who are younger, but scientists are yet to fully understand why this is.
Many of the elderly people who have died have had pre-existing health conditions such as heart disease, lung disease and diabetes, all of which make fighting the virus more difficult, but many have not had any such health problems, and occasionally the virus has caused the deaths of younger, apparently healthy people.
Researchers around the world are racing to learn how the virus behaves, which health factors put people most at risk, and are trying to work out whether there may be genetic traits that could mean some people respond to the infection differently to others.
There are various theories to suggest why the virus is so unusually — and devastatingly — selective.
Some scientists have suggested the greater the amount of virus that infects an individual — known as the “viral load” — could make a large difference to how the body is able to respond to infection.
Put simply, the larger the dose of the virus a person gets, the worse the infection is, and the least promising the outcome.
A parallel school of thought is that genetic variations between humans — differences in our DNA — could affect how susceptible an individual is to the virus.
And another candidate for why apparently healthy young people are dying is they may have a highly reactive immune system, which is sent into overdrive fighting off the virus. In such a scenario, a huge inflammation storm could inadvertently overwhelm vital organs such as the lungs.
https://www.independent.co.uk/news/health/coronavirus-viral-load-genetics-young-people-genes-symptoms-covid-19-a9451101.html