Gene-based vaccines from Moderna, Pfizer and its partner BioNTech are drawing early enthusiasm, but investors are hesitant to up stakes because valuations have soared

Investors are growing more convinced Covid-19 vaccines will work.
They arent as sure shares of vaccine companies can keep soaring.
The investors, along with analysts and others scrutinizing the results from early trials, say the most advanced vaccine candidates didnt cause serious side effects and helped produce antibodies that may be sufficient…