How Did Moderna's COVID Vaccine Results in Teens Stack Up Against Pfizer's?

Pfizer's (PFE 0.71%) COVID-19 vaccine is already available to teens. Moderna's (MRNA 1.39%) might not be too far behind. The company recently announced positive results from a clinical study of its vaccine in children between the ages of 12 and 18. In this Motley Fool Live video recorded on May 26, Motley Fool contributors Keith Speights and Brian Orelli discuss how Moderna's results stack up against Pfizer's.

Keith Speights: Some more news from Moderna, and this is arguably the bigger news. Just this week, the biotech released data for its clinical trial in teens. Brian, I know you have a personal interest in this particular news. What did this study show and how does it compare to Pfizer's data and from a personal standpoint, what's your take?

Brian Orelli: Long-time viewers will know that I have two children that are actually in this clinical trial. It's a clinical trial for adolescents, ages 12 to not less than 18. The main point of the study was to look at antibodies and the teams were non-inferior to adult and is not any worse. Moderna didn't give any numbers to the antibody levels so we don't actually know whether the teens were better or just about the same, but they certainly weren't any worse than adults.

They also looked at efficacy, although this is a small clinical trial. Had 100 percent efficacy based on the strict definition of COVID- 19, but it was really small numbers. There were four in the placebo, four people got COVID-19 in the placebo group and zero in the vaccine group. If you look by the CDC's definition, it's 93 percent.

I think the difference there is that the CDC only requires one symptom before you start testing where the stricter definition then, like the adult clinical trials have used, usually requires two different symptoms before you bother to get a test. That's the difference there between the 100 percent and the 93 percent.

But even 93 percent is a pretty solid level, and teens aren't going to be getting super-sick. Even if you are testing positive, and they obviously only had one symptom that the people who fell in that category had the vaccine. But 10 tested positive, but they obviously had one symptom. It was probably a mild case of the disease.

When comparing it to Pfizer's data, it's not quite apples-to-apples comparison because Pfizer had included 16-18-year-olds in the adult trial, so they did their trial in 12-15 year-olds, and then the antibodies for the 12-15 year-olds were higher than the 16-25-year-olds. They actually gave the levels there. Then they also had 100 percent efficacy with 18 cases in the placebo group and zero in the vaccine group. A little bit more data for Pfizer's vaccine compared to Moderna's in its younger adolescents.

Speights: What's the next step then for Moderna?

Orelli: Well, they're going to go ahead and get the FDA authorization and other regulatory agencies authorizations for the 12-18-year-old. Then hopefully at some point, they unblind us so we know whether my kids got the vaccine or the placebo, and then the people who got the placebo are going to then go to through the entire course again and get the vaccine.

It didn't sound like they were going to do what Novavax did, which is just switch everybody but not tell them. I think it sounded to me like they were going to just give the placebo people the vaccine and the vaccine people could just be dealt with by the state.

Speights: That's right. I didn't even think about that, Brian, that your kids still don't know if they actually received the vaccine itself or placebos.

Orelli: Yeah.

Speights: Hopefully, you will find out very soon.

Orelli: It's on my list of things to do to call them, [laughs] because we have a trip to Hawaii coming up in July. So if we can get them in to get their vaccine if they haven't already done it then that would be ideal.

Speights: We've talked about this in the past. This teen market is a pretty substantial market for Moderna and Pfizer to go after. As a parent of teenagers, what's your take? Do you think the vaccination rates are going to be high with teens or do you think it's going to be iffy?

Orelli: Yeah, I think that's a weird age group, because they're not necessarily seeing their doctor unless they're doing sports or something, but they are not necessarily going in for an annual checkup like younger kids. I think my kids when they hit teenagers, they would go in because they have sports things, but they weren't going in for an annual checkup otherwise. I think that's the time that they'd probably most likely to get vaccinated. We'll have to wait and see how often teens get vaccinated.

The other thing is, it's mild. You tend to be mild cases in teenagers, so is it really worth the side effects which are real versus getting the disease, or potentially getting the disease is sort of a wash may be there, depending on the side effect profile.