1) Natural Immunity
If you get a moderate to severe case of COVID-19, most people maintain viable antibodies for 90 days and memory T-cells for 5 months. This will likely give you natural immunity to the same strain of COVID for up to 5 months. The resistance to the UK variant is thought to be diminished. The resistance to the South African variant is thought to be none. There is some concern that COVID may erase all or part of your T cells’ memory for other pathogens.
2) Vaccines
You should anticipate that vaccines will give you a very similar immune response as the natural immunity acquired from contracting COVID. It doesn’t matter which vaccine you receive. You should get whatever vaccine you can get and as soon as possible. You should anticipate needing to get vaccinated every 90 days once vaccines are developed for all the different variants.
The message is — we have to stop the community spread and exponential rise in variants WORLDWIDE. Individual countries can not obtain herd immunity.