AstraZeneca revises COVID vaccine data with lower efficacy rate of 76%
AstraZeneca Plc’s Covid-19 vaccine, which faced a fresh onslaught of questions this week, was 76% effective in a latest US study.
Washington: AstraZeneca issued updated phase three trial data for its Covid-19 vaccine on Wednesday after facing accuracy questions earlier this week surrounding a preliminary report from its US study.
The company issued the new analysis in a statement on Thursday after an independent monitoring board expressed concern that the initial efficacy of 79% relied on outdated information. The earlier reading was based on data gathered through February 17.
The latest twist created another layer of uncertainty for a product already facing dwindling public support in Europe following months of confusion and missteps. The data glitch may delay the shot’s ability to win US regulatory clearance, although it will likely still play a crucial role in curbing the global pandemic.
A slate of US health officials criticized the company in recent days for what some claimed was data cherry-picking in an effort to make the results appear more favourable.
“The primary analysis is consistent with our previously released interim analysis and confirms that our Covid-19 vaccine is highly effective in adults, including those aged 65 years and over,” said Mene Pangalos, the company’s executive vice president of BioPharmaceuticals research and development. “We look forward to filing our regulatory submission for Emergency Use Authorization in the US and preparing for the rollout of millions of doses across America.”
The findings were based on 190 symptomatic cases that developed among the 32,449 volunteers who participated in the trial, which includes 49 cases that weren’t counted as part of the initial analysis. The company didn’t disclose how many of those cases occurred in the vaccine arm and how many in the placebo arm.
There were 8 cases of severe disease, all in the placebo arm.
The findings suggest the vaccine is more effective in patients aged 65 and older than previously understood, with a newly reported efficacy rate of 85% for that population, up from a previously stated 80%.
The US trial data was deemed important because earlier numbers from research conducted in the UK and Brazil also sowed confusion by producing two different efficacy readings. Plus, those tests failed to include enough elderly people to establish efficacy for that crucial patient group.
AstraZeneca faced a separate backlash in recent weeks over reports of blood clotting in conjunction with its vaccine, which is already approved and in use by dozens of countries around the world. Several European nations suspended, then resumed, use of the vaccine after independent safety reviews.
(With inputs from agency)