Pfizer-BioNTechPfizer (NYSE:PFE) and BioNTech SE (Nasdaq:BNTX) have shared positive data from a Phase 2/3 clinical study testing a third 10-µg dose of the Pfizer-BioNTech COVID-19 vaccine in healthy children aged 5 through 11.

The most recent data show that a booster dose of the BNT162b2 vaccine led to increased neutralizing titers for the omicron variant and wild-type strain of SARS-CoV-2 compared to two doses. In particular, a sub-analysis of 30 sera from the Phase 2/3 study indicated that a third dose resulted in a 36-fold increase in neutralizing antibody titers for the omicron variant compared to two doses.

The Phase 2/3 clinical trial analysis included data from 140 children aged 5 through 11 years old who received three 10-µg doses of vaccine. In addition, participants received a booster dose approximately six months after a two-dose primary series.

Pfizer and BioNTech intend to seek emergency use authorization (EUA) for a booster dose in the near future and share the data with regulatory authorities in Europe.

The two companies report that more than 10,000 children under 12 have participated in clinical trials related to their COVID-19 vaccine to date.

The two-dose primary series of the Pfizer-BioNTech COVID-19 vaccine had won emergency use authorization from FDA for children 5–11 in October 2021.

PFE shares ticked up 0.53% to $53.37, while BNTX shares fell 1.66% to $176.41 in mid-day trading.