Sanofi (SNY 1.84%) and GlaxoSmithKline (GSK 2.11%) hit a bit of a speed bump with their coronavirus vaccine, which didn't produce a robust immune response in clinical trial participants 50 and older. In this video from Motley Fool Live, recorded on Dec. 14, Corinne Cardina, bureau chief of healthcare and cannabis for Fool.com, and Fool.com contributor Brian Orelli discuss the data and how the vaccine differs from the currently authorized vaccines. They also talk about Sanofi and GlaxoSmithKline's backup plan to save the program.

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Corinne Cardina: Sanofi and GlaxoSmithKline, they announced last week that their vaccine candidate failed to stimulate the desired immune response, and this was in the age group of 50 and older. So they're going to be delaying the availability to the second half of 2021. Can you remind us what approach their vaccine is taking, and what are they going to do to figure out the way forward in the wake of this disappointing news?

Brian Orelli: So this a more traditional protein-based vaccine. So they are putting in one of the proteins that is on the outside of the virus. Sanofi is making the protein, and then GlaxoSmithKline makes an adjuvant, so that's something that stimulates the immune system to react to the protein. This is downstream of the mRNA vaccines, Pfizer and BioNTech and then Moderna, and then even farther downstream from the adenovirus vaccines like Johnson & Johnson and AstraZeneca.

It's not unusual to see older patients have a muted response, but it's important for the final vaccines to have it work both in younger patients and in older patients. The new formulation of the protein appears to work better in animal studies. They're going to test it in humans next. The plan is -- rather than taking the older formulation into phase 3 -- they're going to test the new formulation in a phase 2b study, and then hopefully, once they prove it works better than the old one in humans, they're going to run that in phase 3.