World Health Organization says Africa's rollout of COVID-19 vaccine is being hampered by supply shor

Top government scientist says COVID-19 patients would require two doses, three weeks apart and 'a lo

Chinese company aims to vaccinate 6,000 people between the ages of 18 and 75

Scientists warn the headlong rush could backfire

It took 20 months before a vaccine against severe acute respiratory syndrome, SARS, was ready for cl