China's Sinovac vaccine under fire for its low potency, especially against the delta variant of Covid-19 originating in India

The World Health Organization continues to stand by AstraZeneca's Covid-19 vaccine, following concerns in a number of countries over blood clots

A Covid-19 vaccine trial by Johnson & Johnson has been paused after a study participant incurred an “unexplained illness”

Johnson & Johnson is in the midst of several negotiations with various countries for its potential Covid-19 vaccine