Novavax (NASDAQ:NVAX) lags behind bigger players in the COVID-19 vaccine arena such as Pfizer and Moderna. However, in late January the biotech announced very promising results from a late-stage study of its experimental coronavirus vaccine. In this Motley Fool Live video recorded on Feb. 1, "The Wrap" host Jason Hall and writer Keith Speights discuss why Novavax's COVID-19 vaccine results were so stellar.

Jason Hall: The next one here. This is the fourth one that's high on radars right now, is Novavax. Just announced some results from this late-stage study. What's your big takeaway here from these results?

Keith Speights: Yeah. Novavax came out with stellar results. I think the stock jumped over 60% on Friday after they reported their results. Their efficacy was 89.3%.

At first glance, you would say, "Hey, that's great." Still a little lower than Moderna and Pfizer. Well, again, we have the mix of the different variants in their results. They were able to do some post-hoc analysis that looked at the individual variants and what the impact was. They found that against the original COVID-19 strain, their efficacy was 95.6%.

Against the original strain, they were actually higher than even Pfizer. Against the U.K. variant, they had an 85.6% efficacy. Again, very good against this U.K. variant.

Where the issues probably are going to come in is with the South African variant. Novavax also released results from a phase 2b study that was conducted in the country of South Africa. Most of the people had this South African variant, what they're calling an escape variant, and the efficacy there was significantly lower. I have a 60% in participants who were HIV negative, and only around 49% or so in participants who had HIV or [were] HIV positive. Much lower efficacy, but still showing some protection there even with the South African variant.