Pfizer shares, which had risen Tuesday morning after improved demand for the Covid vaccine, dropped 2.3% after Kennedy's nomination moved forward.

Pfizer's fourth quarter beat expectations on strong sales of its Covid vaccine and pill, bolstering its sales as it seeks to fend off criticism from an activist investor that has argued the company squandered its pandemic gains and needs a new path forward.

(Reuters) -Drugmaker Pfizer posted a better than expected fourth quarter profit on Thursday, helped by cost cuts and a smaller-than-feared drop in sales of its COVID-19 vaccine. "Our revenue volatility is largely in the past as COVID-related uncertainties have diminished,