Oxford-AstraZeneca vaccine effective, further scrutiny needed among elderly

The Pfizer-BioNTech shot, approved in Britain last week, could be cleared in the U.S. as soon as this week and the European Union by the end of the year as governments race to overcome contagion

On the day Britain began immunizing its population with a Covid-19 shot developed by Germany’s BioNTech SE and the U.S.’s Pfizer Inc., a peer-reviewed study of the U.K.’s homegrown vaccine left some key questions unanswered.

While trial results published Tuesday in The Lancet found that a vaccine developed by the University of Oxford and AstraZeneca Plc is safe and effective, more analysis will be needed to see how well it works in people over 55, among those at higher risk from the pandemic.

Because older adults were recruited to the studies later than younger ones, “they’ve had less time for cases to