It's been a rocky few months for those stocks as sales of Covid shots and treatments plummet in the U.S.: Shares of all four companies are down more than 20% for the year. But Wall Street's enthusiasm for Covid vaccine makers is getting a fresh boost with the upcoming launch of brand-new shots this fall and the emergence of new variants of the virus.
That includes EG.5, also known as "Eris," which is now the dominant Covid strain in the U.S. Health experts told CNBC that Eris may be slightly better at evading immunity from previous vaccinations and infections, but the variant isn't expected to be more severe.