Comment by adgjlsfhk1

virus mutation rate is proportional to number of infected people, so pandemics will naturally mutate faster. also, the vaccines have been adapted quickly. the pfizer bivalent booster came out 18 months after the regular covid vaccine (9 months after omnicron started circulating) and had extra omnicron protection. that's really fast for drug development (and approximately all of that time was the clinical trial. it's not hard to imagine in a decade or two, that we'll be able to speed up the approval time further as the manufacturers and regulators have more experience with mrna vaccines).