Investors should trim their bets on Pfizer until the pharmaceutical giant shows what’s next for the company after the success of its Covid-19 vaccine, investment firm Mizuho said in a note to clients.

Pfizer beat earnings expectations on the top and bottom lines on Tuesday in a first-quarter report that Mizuho analyst Vamil Divan called “stunning.” However, Divan downgraded the stock to neutral from buy on Thursday, saying in a note to clients that it wasn’t clear what the next upside driver would be.