The B1351 coronavirus variant from South Africa poses a threat to the currently authorized vaccines from Moderna (NASDAQ:MRNA) and BioNTech (NASDAQ:BNTX)/Pfizer (NYSE:PFE) because they weren't specifically designed to protect against that variant. In this video from Motley Fool Live, recorded on Feb. 22, Fool.com contributors Brian Orelli and Keith Speights discuss the ins and outs of the vaccines' potential to protect against the variants and what the companies are doing to deal with the new challenge.

Brian Orelli: We got some data last week published in the New England Journal of Medicine on the coronavirus vaccines protecting against the South African variant -- that's the B1351 -- by Pfizer and BioNTech vaccine, the neutralization was weaker by about two-thirds. And then Moderna's vaccine also produced lower binding to the South African variant compared to the original coronavirus.

These are laboratory tests, so they take serum from people who were vaccinated and then look and see what they can block the virus from injuring cells in the test tube or a petri dish. It seems like, it's sort of difficult to interpret that result and figure out exactly what it means, and what does that two-thirds mean, and how much is that kind of result in natural infection in humans, compared to a clinical trial like the one that Novavax (NASDAQ:NVAX) ran?

Keith Speights: Yeah. Anytime we have pre-clinical results like this, you do have to take them with a grain of salt, to some degree. However, like you mentioned, Novavax had some clinical data that showed their vaccine was less effective against the South African variant, although still pretty effective. I think, based on the totality of the findings that we've seen so far for multiple vaccines, it seems safe to say at this point that pretty much all of the vaccines are going to be significantly less effective at providing protection against the South African variant. Now, that doesn't mean they won't be effective enough, but I think everything we've seen thus far is that the vaccines are less effective against this particular variant. Again, though, even a lower efficacy could still be enough to reach herd immunity, and especially the case if this new South African variant doesn't become as prevalent as some of the other strains. I don't think it's anything to really worry about at this point, but obviously, everything we're seeing so far is that the vaccines aren't going to be quite as effective against this variant.

But several companies are planning to test boosters and or bivalent shots targeting the new variant. Pfizer, Moderna, Novavax are all moving forward with efforts to do this, so I think we'll see some more news over the next -- probably in the second half of this year about booster shots or versions of the existing vaccines that could be more effective against this new variant.

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