Ok, But I haven’t had a cold or flu or any sickness of any kind in almost 30 years, I got the FAUCI FLU in January 2020 and it gave me a mild head cold for 3 days. Obviously Natural Immunity lasts longer than 3 years. I gave it to my Wife and she was really sick for 2 weeks. When I spoke with my Immunology doctor, he agreed with me, in private of course.
My daughter works in the Hospital and is around the FAUCI FLU patients daily, she has not got it again and neither have any of us.
Not the case. Immunity (whether from a vaccine or from an infection) depends on whether the neutralizing antibodies remain effective against the pathogen. If the antibody attachment sites are altered because of a change in the protein structure (typically a result of changes to the folding pattern caused by an amino acid difference), neutralizing antibodies will become less effective or completely ineffective.
This happens all the time with Influenza. That's why people can get the flu year after year. Sometimes twice in the same year. Influenza virus rapidly mutates and that presents a number of challenges. We've already observed this for COVID-19 with the Brazil and South Africa variants. They show resistance to the neutralizing antibodies generated for the April 2020 variant (basically the antibodies sort of still fit, but not very well). Those who had a mild or asymptomatic case of COVID-19 with the April 2020 variant are susceptible to the Brazil or South Africa variants because the levels of neutralizing antibodies present in their body isn't sufficient to effectively bind to all the S-proteins on the new variants.
That's the risk: being exposed to sufficient quantities of the wrong variant. It's also not the end of the world. But it's something we need to keep in mind and evaluate as part the decision making process in terms of what our individual risk appetite is. Along with that it's important to know whether those particular variants are even present in your area. If nobody near you has the Brazil or South Africa variants, then there's not a risk from those.