The ongoing Phase 3 clinical trial of Pfizer/BioNTech's coronavirus vaccine has confirmed its protection lasts at least six months after the second dose.
The companies said that the vaccine remains more than 91 per cent effective against disease with any symptoms for six months.
The vaccine also appeared to be fully effective against the worrying B.1.351 variant of the virus -- which is the dominant strain circulating in South Africa and which researchers feared had evolved to evade the protection of vaccines.
"The vaccine was 100 per cent effective against severe disease as defined by the US Centers for Disease Control and Prevention (CDC), and 95.3 per cent effective against severe Covid-19 as defined by the US Food and Drug Administration (FDA). Safety data from the Phase 3 study has also been collected from more than 12,000 vaccinated participants who have a follow-up time of at least six months after the second dose, demonstrating a favorable safety and tolerability profile," Pfizer and BioNTech said in a joint statement.