Washington, 22 August 2022 (dpa/MIA) — US pharmaceutical giant Pfizer and its German partner BioNTech have requested the US Food and Drug Administration authorize their reformulated Covid-19 booster shot that targets two SARS-CoV-2 Omicron subvariants now in wide circulation. The booster jab has been tweaked for the SARS-CoV-2 Omicron BA.4 and BA.5 subvariants for people aged 12 and older. A corresponding application to the European Medicines Agency is also expected to be completed in the coming days, the companies said. Pending authorization, the doses will be available to ship immediately, they added. There is not yet a clinical trial for the BA.4/BA.5 version of the booster. The companies previously announced safety and tolerability data from Phase 2 and 3 trials of a 30-microgram booster dose of their BA.1-adapted vaccine candidate, which combines the existing vaccine and a vaccine targeting the SARS-CoV-2 Omicron BA.1 variant spike protein. The SARS-CoV-2 Omicron BA.1-adapted bivalent vaccine elicited a superior immune response against the Omicron BA.1 variant compared to the companies' current Covid-19 vaccine. But BA.1 has since been displaced by other subvariants in recent months, prompting the need for further reformulations.