Why not give two different vaccine shots at the same time? That's exactly what Pfizer (PFE 1.42%) is evaluating in a clinical study, with senior adults receiving a booster dose of its COVID-19 vaccine simultaneously with the company's pneumococcal conjugate vaccine. In this Motley Fool Live video recorded on May 26, Motley Fool contributors Keith Speights and Brian Orelli discuss Pfizer's efforts on this front.

Keith Speights: Pfizer announced this week that the first participants have been dosed in a study where the company is evaluating a third booster dose of its COVID-19 vaccine with senior adults at the same time as the senior adults receive Pfizer's 20-valent pneumococcal conjugate vaccine. We've talked about the prospects in the past for a combo COVID flu vaccine. But what do you think about the significance of this effort by Pfizer to give this pneumococcal conjugate vaccine at the same time as a booster dose of its COVID vaccine?

Brian Orelli: You still get two shots. [laughs]

Speights: This is not a combo. This is just two shots at the same time.

Orelli: Maybe they'll try to combine them at some point. But right now you're still going to end up getting two shots. The purpose seems to be to sell more of its pneumococcal vaccines. If you come into the doctor for a COVID booster, if you're old enough to also get pneumococcal vaccine, maybe they give you one in each shoulder. The doctors would probably really like to know that's not going to cause a problem to give it both at the same time.

This is clearly just, as far as I can tell, a study that Pfizer is running to get more sales of its pneumococcal vaccine. People are going to come in for the COVID vaccine and then the doctor's like what else can we do for you while you're here anyway? [laughs]

Speights: How many times can we stick you while you're here? [laughs]

Orelli: What other problems you have, that sort of thing. I think that's probably the main reason why Pfizer is doing this is just a, it's basically a safety study and to confirm that that getting both vaccines together will result in antibodies levels that are pretty close to the levels if you just got one of them or one or the other at that time. That way the doctors can feel like they can do both at the same time.

I think the one interesting thing here, reading between the lines, that would imply that Pfizer expects boosters to be given more by a primary care physicians or for somebody going to the pharmacist rather than big vaccine clinics. Because I would imagine that big vaccine clinics that were specifically doing COVID vaccines, probably aren't going to carry the pneumococcal vaccines as well. They are doing this specifically for those setups in primary care physicians offices or pharmacists who might want to up-sell the patients to an additional vaccine that they need.

Speights: Yeah, I think you're right, and I think Pfizer's right. I think that is where things are headed. We're already seeing that. We're already seeing a lot of primary care physicians now giving the COVID-19 vaccines. I think that's going to be the operating norm going forward. I think you're exactly right on that.