Johnson & Johnson (NYSE:JNJ) has faced multiple challenges with the launch of its COVID-19 vaccine. However, the healthcare giant recently reported good news related to efficacy of its vaccine against the highly contagious delta variant. In this Motley Fool Live video recorded on July 7, Motley Fool contributors Keith Speights and Brian Orelli discuss whether or not J&J's vaccine could make a comeback because of the delta variant.

Keith Speights: Johnson & Johnson recently reported what the company referred to as positive new data for its single-dose COVID-19 vaccine in protecting against the delta variant.

Brian what stood out with J&J's latest data? Do you think the Company's vaccine maybe could make a comeback of sorts if its efficacy is really strong against the delta variant?

Brian Orelli: This study looked at and neutralizing antibodies and blood samples so they're not looking at the ability of the vaccine to prevent infections, they're just looking at the antibodies that participants in the clinical trial developed.

The study did show that there was better neutralizing of the delta variant compared to the beta variant, which I think beta is from the U.K., and Johnson & Johnson has some data that the prevention of the beta variant, where it was effective against the beta and zeta variants that we're prevalent in the phase 3 study run in South Africa.

So Johnson & Johnson's vaccine is going to get used in the developing world because it's effective with just one dose and having one dose, especially in the developing world, is key because you're not to bring people back 28 days later for a second dose.

I doubt this data will do much to help its comeback in the U.S. but if it holds up it will keep the vaccine from becoming obsolete globally because obviously if it can protect against the delta variant then it will get used globally a lot, longer than it would if it had to peter out because the delta variants -- wasn't protecting against the delta variant.

In the release, there is also some data that showed that the participants in the phase 1/2a study had T cell responses that lasted at least eight months and so that's good news because it's also showing that it protects longer, probably you don't need a booster shot for at least eight months because clearly they had T cells that were able to attack cells that have been infected with the virus that causes COVID-19.

Speights: Brian, I don't have the reports pulled up in front of me but J&J isn't the only company whose vaccine seem to produce pretty good levels of neutralizing antibodies against the delta variant and I think there have been some studies with somewhat similar results anyway for Pfizer, BioNTech, and maybe Moderna as well.

Orelli: Yeah. It's hard to tell with these neutralizing antibodies what level is sufficient but Johnson & Johnson is arguing that if their neutralizing antibody is better against the delta variant than the beta variant and they showed that in clinical trials they protected against beta variant actual head-to-head against placebo.

More people got the beta variant than people who got the vaccine. That probably means that if the delta variant neutralizing antibodies is higher than the beta variant then that probably means it's protecting against the delta variant, but it's hand waving and A is greater than B is greater than C and it's not the ideal situation for scientists, but we'll take it if that's how we get it.

Speights: No matter how you look at it, this is good news for Johnson & Johnson and the company has needed some good news for its vaccine. It's run into quite a few problems over the last several months.

Orelli: I'm under the conclusion that Johnson & Johnson's vaccine is probably going to be harder to create a booster shot with because it uses a virus and then people are going to get tolerant to the virus that delivers the DNA that expresses the coronavirus protein.

I think that the longer it can last the better for Johnson & Johnson, whereas the other companies, the mRNA companies can develop boosters and so ironically, it's better for them to not have long-lasting vaccines because then they can sell their booster shots.

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