There are two coronaviruses that cause the common cold. Another one caused bronchitis and a fourth caused pneumonia.
So I was right - I saw the doctor that did the study on YouTube. The T cells attack the inner protein of the Corona Virus, not the Spike Protein. Spike proteins constantly mutate, but the inner protein stays constant. So it is possible to create a vaccine that will be sufficient against all varieties of the Corona virus, since the inner protein is nearly identical in all variants.