[turk-]

Yes. And there is a small possibility that something even worse happens for those previously infected/vaccinated called antibody-dependent enhancement (ADE). ADE occurs when the antibodies generated during an immune response recognize and bind to a pathogen, but they are unable to prevent infection. Instead, these antibodies act as a “Trojan horse,” allowing the pathogen to get into cells and exacerbate the immune response.

The worst case with a new covid strain would be if people who were vaccinated by a previous vaccine or infected by an older strain experience antibody-dependent enhancement after being infected with the new strain. This is where the body recognized the new strain as the old and starts producing anti-bodies. These anti-bodies actually assist the new strain in infecting your cells, making the disease worse.

ADE has not been detected with any covid strains/vaccines so its not something to worry about for now but who knows what may happen in the future. I've been keeping my eye out for any news of ADE with any of these new strains.

Certain viruses like dengue fever can be much worse if you had previously caught a different strain due to ADE.

https://www.chop.edu/centers-programs/vaccine-education-cent...

[timbit42]

Since the current vaccines are based on recognizing the spike protein, and since this South African (Nu?) variant has many mutations on the spike protein, what are the odds that a vaccinated person's immune system would recognize the mutated spike protein as being the same as the original one?

[turk-]

No idea. Time will tell but a high number of mutations is not ideal.