There are two groups of people whose COVID-19 infection rate is relatively low. One is a child, and children account for less than 2% of the confirmed cases. This may be because children have innate resistance, and the amount of air inhaled by children is relatively small compared with adults, so the probability of infection is relatively low.
Second, give up halfway. For those old smokers who have difficulty in quitting smoking, the probability of being infected with COVID-19 is 1 times higher than that of ordinary people, the probability of being hospitalized is five times higher, and the probability of dying from a new crown is as high as 10 times. Smoking itself will increase the chance of getting lung cancer, and the lung's ability to resist viruses will also be reduced, which makes it easier to get infected with COVID-19.
There is no clear answer as to why these selected sons are still not infected with the virus after close contact with those infected in COVID-19. The future needs to be explored. What we can do now is to protect COVID-19 and look forward to the day when COVID-19 is completely conquered.