SARS-CoV-2 variants BA.4 and BA.5 show substantial immune escape compared with BA.1 and BA.2
Pfizer Covid Vaccine Protects Against Omicron Sublineages BA.4 and BA.5: Study - Bloomberg
La Comisión Europea autoriza la vacuna de Pfizer para otras dos subvariantes de Ómicron
Deutsches Primatenzentrum: Emerging Omicron subvariants BA.2.12.1, BA.4 and BA.5 are inhibited less efficiently by antibodies
News - CHMP Recommends Additional Authorisation Modification of Comirnaty (BioNTech/Pfizer) As a Bivalent Vaccine Adapted to Omicron BA.4/BA.5 for Booster Vaccinations - Paul-Ehrlich-Institut
El Reino Unido aprueba las vacunas de Pfizer y BioNTech - YouTube
Por qué las contagiosas nuevas variantes BA.4 y BA.5 de Ómicron están causando un repunte de brotes de COVID | National Geographic
A Bivalent Omicron-Containing Booster Vaccine against Covid-19 | NEJM
Pfizer, BioNTech say bivalent COVID-19 booster shot performs better against BA.5 omicron subvariant - ABC News