Omicron Variant Has Covid-19 Vaccine Makers Preparing for Worst Case

Drugmakers raised the prospect that existing Covid-19 vaccines might be less effective against the new Omicron variant of the coronavirus, which could create a need for modified vaccines that better target the concerning new strain.

The prospect of new demand for booster shots, as well as medicines to treat disease caused by the new strain, have lifted the stock prices of several drug companies in recent days, including Pfizer Inc. and Moderna Inc. Though the knowledge of Omicron is limited at this point, investors are already making bets that its emergence will become a significant source of sales for drugmakers.