“How do they know it protects against a new strain....”
Likely through isolating the strain and infecting monkeys. When I volunteered for the Moderna study they explained that one of the tests performed was vaccinating monkeys and then infecting them with the Covid virus. None of the vaccinated monkeys got sick. None.
I imagine the same protocol is being used now for the variants. They can intentionally infect monkeys, they can’t intentionally infect humans.
Thanks for the information.
I bet PETA would be livid to know/hear they experimented with monkeys. sarc off