As Pandemic Worsens, Why AstraZeneca Vaccine Is In Spotlight

As immunization programs gather pace around the world, another vaccine ran into trouble on Wednesday when Hong Kong and Macau suspended the Pfizer-BioNTech jab over what authorities said were packaging problems.

AstraZeneca has said it is standing by its coronavirus vaccine after a US agency raised concerns about trial results that showed the shot to be highly effective in preventing Covid-19. As immunization programs gather pace around the world, another vaccine ran into trouble on Wednesday when Hong Kong and Macau suspended the Pfizer-BioNTech jab over what authorities said were packaging problems. The uncertainties are a blow to scientists' hopes for a quick rollout of what they say is the best hope of ending a pandemic that has killed more than 2.7 million people. AstraZeneca had published results from its US trials on Monday, showing the vaccine to be 79 percent effective in preventing Covid-19, but the US National Institute for Allergies and Infectious Diseases raised concerns that the results were outdated.