A healthcare professional will prepare a dose of the Oxford / AstraZeneca Covid-19 vaccine at the vaccine center at the Brighton Center in Brighton, southern England on January 26, 2021.

Ben Stensall | AFP | Getty Images

LONDON – The results of a large US study showed that the coronavirus vaccine developed by AstraZeneca and the University of Oxford is 79% effective in preventing symptomatic illness and 100% effective against serious illness and hospitalization.

The vaccine’s safety and efficacy analysis published on Monday was based on 32,449 participants from a Phase 3 study.

By comparison, Moderna’s vaccine was found to be greater than 94% effective in preventing Covid, and Pfizer-BioNTech’s vaccine was found to be 95% effective.

AstraZeneca announced that it will continue to analyze the data and prepare for the primary analysis to be submitted to the US Food and Drugs Administration for emergency approval in the coming weeks.

It comes shortly after a spate of countries temporarily suspended the use of the shot after reports of blood clots in some vaccinated people. Health experts sharply criticized the move, citing a lack of data, while analysts expressed concerns about the impact on vaccine uptake as the virus continues to spread.

Germany, France, Italy and Spain, among others, have resumed use of the Oxford-AstraZeneca vaccine after the European Medicines Agency found the shot was both safe and effective in its initial investigation into possible side effects.

The World Health Organization and the International Society on Thrombosis and Hemostasis have recommended that countries continue to use the Oxford-AstraZeneca vaccine.

AstraZeneca said in a press release Monday that an independent board had not identified any safety concerns related to the shot. With the help of an independent neurologist, they also performed a specific check for blood clots as well as cerebral venous sinus thrombosis (CVST), an extremely rare blood clot in the brain.

The Data Safety Monitoring Board “found no increased risk of thrombosis or events characterized by thrombosis in the 21,583 participants who received at least one vaccine dose. The specific search for CVST found no events in this study.”

AstraZeneca’s shares traded nearly 1% early this morning.

“Urgently needed” additional vaccination option

Ann Falsey, Professor of Medicine in the School of Medicine at the University of Rochester, USA, and Co-Lead Principal Investigator for the study, said, “This analysis validates the AstraZeneca COVID-19 vaccine as a much-needed additional vaccine option and offers adults confidence all ages can benefit from protection against the virus. “

The drug company said the shot was well tolerated and its effectiveness was consistent in terms of ethnicity and age.

In particular, the Oxford-AstraZeneca shot was 80% effective in preventing Covid in participants 65 and over.

A healthcare worker receives the Oxford-AstraZeneca Covid-19 vaccine at Chang Gung Memorial Hospital in Taipei, Taiwan on Monday March 22, 2021. Taiwan started vaccinating against coronavirus today.

I-Hwa Cheng | Bloomberg | Getty Images

“These results add to the growing evidence showing that this vaccine is well tolerated and highly effective against all degrees of COVID-19 and across all ages,” said Mene Pangalos, executive vice president of BioPharmaceuticals R&D at AstraZeneca. in a statement.

“We are confident that this vaccine can play an important role in protecting millions of people worldwide from this deadly virus,” said Pangalos.

Among the participants in the interim analysis, around 20% were 65 years of age and older, while around 60% had comorbidities that were associated with an increased risk of progression to severe Covid such as diabetes or heart disease.