BRUSSELS, BELGIUM - DECEMBER 21: A smartphone displays a digital vaccination certificate passport for COVID-19 to travel within the European Union (EU) in Brussels, Belgium on December 21, 2021. As of February 1, 2022, the Commission adopted rules relating to the EU Digital COVID Certificate, establishing a binding acceptance period of 9 months (precisely 270 days) of vaccination certificates for the purposes of intra-EU travel. Dursun Aydemir / Anadolu Agency/ABACAPRESS.COM