On Monday, British pharmaceutical giant AstraZeneca said an interim analysis of clinical trials showed its coronavirus vaccine has an average efficacy of 70% in protecting against the virus.
After a string of encouraging vaccine results in recent weeks, it comes after late-stage trial readouts from Pfizer-BioNTech and Moderna.
It is hoped a Covid vaccine could bring an end to the coronavirus pandemic that has claimed more than 1.3 million lives worldwide.
AstraZeneca said its vaccine, developed in collaboration with the University of Oxford, was assessed over two different dosing regimens.
One showed an effectiveness of 90% when trial participants received a half dose, followed by a full amount at least one month apart. The other dosing regimen showed 62% efficacy when given two maximum doses at least one month apart.
According to the world health organization, there are currently about 170 projects in the world to develop a coronavirus vaccine.