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 safety and efficacy analysis of the AstraZeneca vaccine published on Monday was based on 32,449 participants in 88 trial centers in the United States, Peru and Chile.

Data from the late-stage human study again confirms that the Oxford-AstraZeneca vaccine is safe and highly effective.

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

AstraZeneca said it will continue to analyze the data and prepare for the primary analysis to be submitted to the U.S. Food and Drug Administration for emergency approval in the coming weeks.

The results come soon after several countries temporarily suspended shot use following reports of blood clots in some vaccinated individuals. 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 safe and effective during 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, a specific review of blood clots as well as cerebral venous sinus thrombosis, an extremely rare blood clot in the brain, was also carried out.

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 were trading 2% in London on Monday.

“US regulators are reluctant to rely entirely on data obtained outside of the US, even during a pandemic. Therefore, this study was conducted to provide convincing evidence of the efficacy and safety of a sufficiently large number of US patients.” said Stephen Evans. Professor of Pharmacoepidemiology at the London School of Hygiene & Tropical Medicine.

“This is good news for the world community and it is hoped that any political statements related to this good news will be avoided,” Evans said.

“Urgently needed” additional vaccination option

Dr. Ann Falsey, Professor of Medicine in the University of Rochester School of Medicine 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 the confidence of adults of all ages can benefit from protection against the virus. “

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

The vaccine was 80% effective in preventing Covid in participants aged 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.

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

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

The phase 3 study, led by AstraZeneca, involved two doses of the Covid vaccine given four weeks apart.

The drug company said previous studies had shown that longer intervals, up to 12 weeks, showed greater effectiveness, suggesting that intervals longer than four weeks could increase effectiveness and speed up the number of people taking their first dose can get.