Concerns about coronavirus news out of China may have moved some vaccine-maker and travel stocks Friday. 

Shares of Moderna (MRNA), Pfizer (PFE) and Novavax (NVAX) all gained Friday, a broadly downbeat session that saw the S&P 500 slide 1.7%. Moderna was the biggest gainer on the benchmark index, rising more than 5%. Some stocks associated with international travel, meanwhile, retreated: Norwegian Cruise Lines (NCLH), which fell more than 6%, was among the index’s top decliners. 

Some of the share moves may be attributable to investors’ assessment of reports from the South China Morning Post, Daily Mail and other outlets saying that a team of Chinese researchers in a scientific journal said it identified a bat coronavirus that might be able to move from animals to humans. 

Asked about the reports on CNBC Friday, former FDA Commissioner Scott Gottlieb said that “we find these things pretty routinely” and “I think the link to an imminent risk here is pretty flimsy, quite frankly.”

The moves came as stock markets were buffeted by a range of other forces. Reports that the Justice Department was investigating UnitedHealth Group (UNH) was bad news for health insurers’ shares, while earnings news dragged some tech shares lower. 

Some market watchers saw the move lower in markets as driven by economic data and policy uncertainty. Cruise stocks had been hit earlier this week after Commerce Secretary Howard Lutnick said they might be subjected to U.S. taxes.