What happened While the latest news about BioNTech (NASDAQ: BNTX) was generally positive, investors didn't greet it warmly on Wednesday. The German biotech's shares fell by nearly 4% on the day. So what Pfizer (NYSE: PFE), BioNTech's partner in the development of top coronavirus vaccine Comirnaty, issued an update that morning on the jab. It was a good news/bad news update, with the good being that a booster dose of the vaccine managed to neutralize the omicron variant of the coronavirus in an initial lab study. Image source: Getty Images. The bad news was that those inoculated only with the initial two-dose regime of the Pfizer/BioNTech shot might not be sufficiently protected against the fast-spreading variant. Nevertheless, the pharmaceutical sector giant wrote hopefully, "as the vast majority of epitopes targeted by vaccine-induced T cells are not affected by the mutations in Omicron, the companies believe that vaccinated individuals may still be protected against severe forms of the disease and are closely monitoring real world effectiveness against Omicron, globally." Investors seem to be troubled by the latter finding, as Pfizer stock also traded down (by 0.6%) on Wednesday, which was a generally upbeat day for the market. Now what BioNTech is more susceptible to perceived negative developments with Comirnaty because, so far, it's the company's only commercialized product. Pfizer, meanwhile, is a huge company with a great many goods on the market. But bear in mind that Comirnaty has been shown to be highly efficacious and a go-to vaccine in many jurisdictions around the world. Here in the U.S., it's still the only coronavirus jab fully approved by the Food and Drug Administration for use. (Two others have received Emergency Use Authorization, but not full approval.) 10 stocks we like better than BioNTech SEWhen our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and BioNTech SE wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of November 10, 2021 Eric Volkman has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source