What happened

Thanks to encouraging developments in Europe, shares of coronavirus vaccine partners Pfizer (PFE 0.12%) and BioNTech (BNTX 2.42%) both rose on Friday. Pfizer inched 0.1% skyward, while BioNTech -- which is headquartered on the continent -- closed the day up 4.8%.

So what

On Friday, Pfizer and BioNTech announced that they formally requested that the authorization for their BNT162b2 coronavirus vaccine be expanded to include adolescents aged 12 to 15 throughout the 27-country European Union (EU).

This follows a similar application the biotech and the pharmaceutical giant made with the U.S. Food and Drug Administration. That request is pending.

A syringe being filled with a vaccine from a vial.

Image source: Getty Images.

Pfizer and BioNTech's  application with the European Medicines Agency is based on a phase 3 trial of BNT162b2 exclusively comprising people of that age group. The results of the 2,260-participant study were highly encouraging -- the vaccine showed 100% efficacy, "robust" antibody responses, and was generally well tolerated.

The vaccine won authorization for emergency use in both the U.S. and the European Union last December. It has been widely administered in both jurisdictions since then.

Now what

Pfizer and BioNTech's partnership stipulates that the latter company is the marketing authorization holder in the EU, as opposed to the two holding that position jointly in the United States. So the biotech stands to gain more handsomely from any expansion there. BNT162b2 has been a standout success, and since its request is likely to be approved given those trial results, we can safely assume that will continue.