"Yet, if you’re vaccinated with AZ, Pfizer, J&J or Moderna, you are 3% as likely to be hospitalized. Yet, 40% of America will take a drug that reduces hospitalization only slightly or in MRK’s case 50%."
You're comparing apples with pears (I think).
The figure you quote for vaccines is among an uninfected population, whereas the Merck drug is used in people who have already contracted mild-to-moderate COVID-19.
Compared to the alternative of "do nothing", they both look like good bets to me.
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