CNBC's Jim Cramer said Wednesday that he was surprised Pfizer released promising early data on its potential coronavirus vaccine, but suggested it was a sign of confidence from the U.S. pharmaceutical giant.
"I want more information. I frankly don't want to just accept it like this, but the market will," Cramer said on "Squawk on the Street," referencing that U.S. stock futures erased earlier losses and turned positive on the news.
"It's kind of a saved-by-Pfizer market from where we were just a few minutes ago," the "Mad Money" host added, before the opening bell on Wall Street. Helped by a surge in Dow-stock Pfizer, the Dow Jones Industrial Average was higher in early trading.
Cramer noted that the early trial results from Pfizer, which is working alongside German drugmaker BioNTech, involved a small sample size. But Cramer said he was encouraged because Pfizer is "not a hype company."
"This is not a company that is a braggart company so I am very surprised to see them come out this early. They must feel a level of confidence that is extraordinary versus what they typically do," Cramer said.
Pzifer and BioNTech are among a number of companies racing to develop a vaccine to prevent the coronavirus, which has infected at least 10.5 million people across the world, according to Johns Hopkins University. More than 512,000 people have died. About a quarter of the global infections and fatalities are in the U.S.
"I want to be hopeful, but I also have to be realistic," Cramer said of Pfizer's early results, which have not yet been peer-reviewed. He noted that the results came from a few dozen patients, when ultimately thousands of people will need to participate in late-stage trials.
Cramer said investors who may want to chase the stocks of Pzifer or BioNTech after Wednesday's news should be cautious, referencing the price action of Moderna's stock on May 18 when it reported early stage data from its vaccine trial.
Shares of Moderna got an initial 30% pop on the announcement but then plummeted over subsequent sessions. As of Wednesday morning, the stock was still off about 10% since then, trading around $60.
"You have to hope for the best, but prepare for the worst when it comes to a vaccine," Cramer said.