Thank you.
Dr. Kochhar, you talked about being up to date, and you gave an example of the flu vaccine. I'm curious about the efficacy of a third or even a fourth booster. Help me understand this, and forgive my ignorance if I don't understand this correctly.
The mRNA vaccines were developed to respond to the spike protein on the first version of COVID-19, which was the alpha version. We have immune escape variants, which by definition are mutating away from that. We've gone through beta, delta, gamma, omicron, and there are others.
Can you help me understand how giving a booster, which boosts antibodies to recognize the original spike protein of the alpha variant, can help produce effective immunity to a virus that has significantly changed since that time?