Are Prospects of a 4th Dose of the Pfizer-BioNTech Vaccine Dwindling?

Results from a study in Israel appear to show that a fourth dose of the COVID-19 vaccine developed by Pfizer (PFE 0.55%) and BioNTech (BNTX 0.58%) isn't great at preventing infection from the coronavirus omicron variant. In this Motley Fool Live video, recorded on Jan. 19, Fool contributors Keith Speights and Brian Orelli discuss whether or not the prospects of a fourth dose are dwindling.

Keith Speights: I mentioned that there were results from a study conducted in Israel and they were announced this week. This study found that a fourth dose of the Pfizer-BioNTech COVID-19 vaccine did not prevent infections from the coronavirus omicron variant. Both of these stocks fell on the news on Tuesday. Are the prospects of a fourth dose of the Pfizer-BioNTech vaccine dwindling, you think?

Brian Orelli: Yeah. The study tested this fourth dose of the vaccine and it did bring the antibody levels back up. But researchers said that that wouldn't actually protect patients from the omicron variant. I think a fourth dose of the original vaccine certainly seems less likely than before.

But Pfizer and BioNTech, as well as Moderna (MRNA 1.69%) and others, are developing omicron-specific boosters. I think there's still hope for the vaccine makers that they can have at least one more round of boosters if the new variant, specific boosters actually work, which we don't know yet. But assuming they actually work, and I think it's likely that would be the case. I think vaccine makers aren't dead in the water quite yet.

Speights: Brian, Moderna stock also fell, although not as much as BioNTech. Do you think investors were just assuming that there would be similar results with the fourth dose of the Moderna vaccine?

Orelli: Yeah. They actually tested Moderna after Pfizer in this study as well. I think that the results are likely to be the same. I think they really need an omicron-specific booster at this point.

Speights: My mom texted me last night asking how long do the third boosters last? My response was, no one knows yet. Have you seen any data at all so far that indicates how long the third booster's efficacy is likely to extend?

Orelli: Yeah. I don't think we have enough people who've been out from a third dose long enough to have a good idea. It becomes really difficult because the way who do you compare it to?

If you're looking at the people who have gotten a third dose, are you comparing it to the people who got two doses? Or I guess that's makes the most sense. But then finding an equal group that you think is equally as likely to get infected, becomes sort of difficult.

You can certainly look at antibody levels and that's after the third dose and look and see if they are watching them decline. You can do that. But actually looking at whether the third dose provides protection from either infection or from severe disease, I think is a little more difficult to measure over time.

Speights: You made a good point, Brian. Any testing of fourth doses of the current vaccines might really be a moot point because Pfizer and BioNTech expect to have their omicron-specific vaccine version ready by March, I think. By the time we might be at a point where fourth doses could be needed, these omicron-specific vaccines could be ready.