COVID-19 vaccines from Pfizer (PFE 0.23%) and Moderna (MRNA 3.28%) are being distributed across the U.S. (and across the world, for that matter). But these vaccines received Emergency Use Authorization before the emergence of new coronavirus variants. One of those variants, first identified in South Africa, could especially present problems.

In this Motley Fool Live video recorded on Feb. 1, Motley Fool contributors Keith Speights and Danny Vena discuss whether or not Americans should be concerned about COVID-19 vaccine efficacy against the new South African variant.

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Danny Vena: Keith, the next question that shows up here, and I was curious about this as well. Is there a reason to be concerned about the lower efficacy rates for these vaccines against this coronavirus variant that was discovered in South Africa? Is that going to necessarily prolong the pandemic? Or are people more at risk? Can you explain that to us?

Keith Speights: Yeah. I think Danny, there is a reason to be concerned, but not a reason to be worried.

The vaccines, at least the two that we've seen that had results that included data about the new variants, in particular the South African variant, the efficacy for these vaccines is lower with the South African variant. That is a concern.

In fact, at least two of the companies are working on testing a booster dose, and even a bivalent version of their vaccine that specifically targets the South African variant. So that hope that can boost their efficacy against it. It's a concern and obviously otherwise these companies wouldn't be looking to do more clinical studies if it were not a concern.

I'm not worried about it at this point though, because 60 percent efficacy is still really good. Like we've said, that's about what we get with flu vaccines. I think that can help curb the spread. It might take us longer to get to herd immunity if the South African variant becomes even more prevalent, which it could. But I am not worried at this point.

Now, could other variants come along that render these vaccines much less effective? Yeah. The answer is yes. More mutations could happen.

The good news is that the new technologies that we have, particularly with these messenger RNA vaccines, they're able to develop vaccines very quickly with mRNA technology. I think we may be playing a little game of whack-a-mole for a while. But at least we have the hammer to hit them all [laughs]. Maybe that's the best analogy.