AstraZeneca US trial data a confidence booster for COVID-19 shot

AstraZeneca’s COVID-19 vaccine performed better than expected in a major late-stage trial potentially paving the way for its emergency authorization in the United States and bolstering confidence in the shot after numerous setbacks in Europe.

The drugmaker said on Monday that trials in Chile, Peru and the United States found the vaccine, developed in conjunction with Oxford University, was 79 percent effective in preventing symptomatic COVID-19, 100 percent effective in stopping severe disease and hospitalization and, crucially, posed no increased risk of blood clots. It intends to request US emergency authorization in coming weeks.

More than a dozen European countries, including Germany and France, had halted use of the AstraZeneca vaccine earlier this month after some reports linked it to blood clots in a very small number of people. They have since resumed inoculation after a regional regulator said it was safe, but an opinion poll on Monday showed Europeans remained sceptical over its safety.

Hailed as a milestone in the fight against the COVID-19 pandemic when it first emerged as a vaccine contender last year, the AstraZeneca shot has since been dogged by confusion over its efficacy, dosing regimen and possible side-effects as well as supply setbacks in Europe.

The latest data should help address some of those concerns, analysts said. Based on more than 32,000 people, the trial was larger and elderly volunteers featured more prominently than in previous trial results from the UK which had prompted some European countries to initially hold back using the AstraZeneca shot on older people.

“It is clear this vaccine has very good efficacy (remember that 60 percent was, prior to any trials being started, regarded as a good target), and that this efficacy does not show a notable decline at older ages,” said Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine

US trials of rival vaccines from Pfizer and Moderna, which are already being deployed in the United States, have showed efficacy rates of around 95 percent.

But the AstraZeneca vaccine is seen as crucial to tackling the spread of COVID-19 across the globe because it is easier and cheaper to transport than rival shots.