Is This New Data on Valneva's Less-Effective Booster Concerning?

French drugmaker Valneva (VALN 4.43%) has high hopes for its COVID-19 vaccine candidate VLA2001. But recent data shows that VLA2001 performed dismally as a booster shot for individuals who received two doses of Pfizer's (PFE 0.49%) and BioNTech's (BNTX 1.07%) vaccine. In this Motley Fool Live video recorded on Dec. 8, Motley Fool contributors Keith Speights and Brian Orelli discuss whether this latest data is a major concern for Valneva.

Keith Speights: Let's move on to another COVID story, Brian. Results were published in The Lancet on Monday, I believe, that showed Valneva's COVID-19 vaccine candidate VLA2001 was the only one out of seven boosters that did not work well with individuals who initially received two doses of Comirnaty, the vaccine developed by Pfizer and BioNTech. Are Valneva's booster hopes on thin ice, or is there more to the story here?

Brian Orelli: The study tested participants just two or three months after the second dose. That's a lot quicker than the current recommendation, which is for six months. I think they were trying to get people quickly, and they were trying to see whether maybe you want to do another booster right before the fall. That was the idea here.

The company, Valneva, believes that the culprit is probably because it's an inactivated virus, and they typically require longer intervals between boosts to show an effect. That's their hypothesis. VLA2001 did increase antibody levels for those people that had been given the AstraZeneca (AZN 0.35%) vaccine 2-3 months before and then given the VLA2001.

It's a little hard to know for sure why an mRNA vaccine, an mRNA plus and then inactivated virus wouldn't cause a boost in antibody levels, but an adenovirus vaccine followed by an inactivated virus would cause a boost. It's possible that maybe just Pfizer is at a higher level, so it's harder to just starting at a higher level. It's harder to see that increase. Where if AstraZeneca's was at a lower level, because I don't think it's quite as effective. Maybe that's the reason why they were able to see the boost with AstraZeneca's but not with Pfizer's.

Speights: This story might not be as bad as it seems at first glance, as it sounds like.

Orelli: I think they definitely need to do more studies, especially do a six-month study because that's when people are actually getting, the most people are getting their boosters.