Pfizer Inc. /zigman2/quotes/202877789/composite PFE +1.90% and German partner BioNTech SE /zigman2/quotes/214419716/composite BNTX +1.47% said Monday they have submitted an application to the U.S. Food and Drug Administration seeking an emergency use authorization for their bivalent vaccine booster for use in children aged 5 to 11 years of age. The application is for a 10-ug booster dose of the vaccine targeting omicron BA.4 and BA.5 subvariants, which have become dominant in the U.S and around the world. The application "is supported by safety and immunogenicity data from the companies' Omicron BA.1-adapted bivalent vaccine, non-clinical and manufacturing data from the companies' 10-ug Omicron BA.4/BA.5-adapted bivalent vaccine, and preclinical data from the companies' Omicron BA.4/BA.5-adapted bivalent vaccine," the companies said in a joint statement. An application for the same age group will be submitted to the European Union regulator in the coming days. The companies have also started a Phase 1/2/3 study to evaluate different doses and dosings of the same vaccine for use in children aged six months through 11 years old. Pfizer shares were down 0.9% premarket while BioNTech was down 0.8%.