Vaccines
The most important understanding about the Covid vaccines, at least those used in the USA, is they are remarkably effective at reducing severe disease.
Nearly everyone sick in hospitals with covid-19 disease has been unvaccinated.
Unfortunately, these vaccines do not provide "sterilizing immunity," preventing transmission of disease. Some vaccines have this ability, others do not. But covid vaccines do REDUCE transmission, the length of infection and the likelihood of contracting "long covid" (lingering after effects that can be damaging in many ways). There have been a few who have wound up in hospitals despite vaccination but in most cases they have been in people with existing major health problems.
People who object to vaccination because the vaccines are not 100% effective are like those who would decline to wear seat belts or bicycle helmets because they are not 100% effective.
Arguments that someone has an immune system (whether a result of divine creation or evolution) and therefore they don't need a vaccine ignore how vaccines work. It's good to have adequate nutrition, sleep, stress reduction, exercise and other healthy activities, but the best thing that can be done for one's immune system is to train it to recognize the intruder so it can mount a vigorous defense if the virus enters the body.
