The company says the press release was based on data gathered until 17 February, when a prespecified cutoff point was reached.
"We have reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis".
"If the United States regulator looks at this data and authorises AstraZeneca, that will carry a lot of weight", said Jimmy Whitworth, a professor of worldwide public health at the London School of Hygiene and Tropical Medicine. The latest phase 3 trial data for the vaccine, coming from the USA, could potentially boost its profile by helping to assuage some prior efficacy and safety concerns.
"The gap between the number of vaccines administered in rich countries and the number of vaccines administered through COVAX is growing every single day and becoming more grotesque every day".
Vietnam began a mass Covid vaccination program using the AstraZeneca vaccine earlier this month, starting with frontline workers.
AstraZeneca's release on Monday of encouraging data about its coronavirus vaccine from its United States trial raised hopes that the drug company could bury doubts about the shot and put a troubled rollout behind it.
After Health Canada approved the shot for all adults, the National Advisory Committee on Immunization (NACI) recommended the product be used only on people under the age of 65, citing a dearth of clinical trial data on the vaccine's effectiveness in older people.
The vaccine has had a rocky rollout, especially in Europe, where it's now at the center of a supply showdown between the European Union and the U.K. Concerns about blood clots just days ago prompted around a dozen countries to suspend immunizations, though most have since resumed using the vaccine.
AstraZeneca shares fell as much as 1.6 per cent in London.
Last week in Bucharest, Romania, vaccination coordinator Valeriu Gheorghita said 33,000 AstraZeneca immunisation appointments had been cancelled in 24 hours and that about a third of the 10,000 people scheduled to receive the vaccine did not show up.
Many millions of people have received the AstraZeneca shot worldwide, including more than 17 million in Britain and the European Union, nearly all without serious side effects. Health officials anxious that those past issues could cause lasting harm to the shot that is key to global efforts to stop the pandemic and undermine vaccine confidence more broadly. The company is planning to seek emergency use authorization from the USA drug regulator. The group notified the National Institute of Allergy and Infectious Diseases, the Biomedical Advanced Research and Development Authority, and AstraZeneca of concerns they had with the data release.
The question remains: do the benefits of the vaccine still outweigh the risks, despite the possible link to rare blood clots with low blood platelets?
Dr. Larry Corey, co-leader of the U.S. Coronavirus Vaccine Prevention Network, which helped design AstraZeneca's U.S. trial, said the monitoring panel's rebuke was something he had not seen before. That's what happened to the AstraZeneca trial in September after a study participant developed neurological symptoms, for example. Investigators ultimately concluded that the illnesses could not be linked to the vaccine. This latest misstep may further delay the emergency authorisation the company is seeking in the US.