AstraZeneca’s Covid-19 vaccine is safe, 79% effective in the late stages of US trials

The shot is already widely used outside the US. However, the US trials reflect the largest scale of vaccination and may boost confidence in its use following questions about the efficacy and serious blood clotting issues in a very small number of people. in Europe who got the shot. The US trials did not identify any increased risk of severe blood clotting.

According to AstraZeneca, participants 65 years and older are shown to have 80% of the vaccine.

Concerns about blood clotting have led to a temporary halt to more than a dozen European countries, including Germany and Italy, using the vaccine this month. Most resumed administration of the vaccine after European and British medicine regulators again endorsed the use of the shot, despite the rare clotting problems, which apparently did not relate to the vaccine. The regulators said they could not rule out a link, but said the vaccine was an important weapon to prevent death and serious illness and that its benefits outweighed potential risks.

There is a lot of focus on the worldwide acceptance of the AstraZeneca shot, which was developed in conjunction with the University of Oxford and is widely used in many parts of the world. The US Food and Drug Administration is expected to review the trial data and may decide to use the vaccine as early as next month.

Previous trial results of the shot from the UK and elsewhere have been criticized for lacking elderly volunteers, who were recruited later in the trial for safety reasons. The UK and other countries used the vaccine in older than 55 years, but some countries initially held back and used the shot only in younger age groups.

The U.S. trial involved 32,449 participants 18 years and older, and about 20% were 65 or older. The efficacy of the vaccine was 100% to prevent serious diseases and hospitalizations, with similar results in all age and ethnicity groups.

The UK trial results of the vaccine, released late last year, offered a range of efficiencies, between 62% and 90%. The range was difficult to compare with the US test results of competing vaccines, one from Pfizer Inc.

and Germany’s BioNTech SE and another from Moderna Inc.

Both are more than 90% effective in US trials.

The US trial results have not yet been reviewed by independent researchers. AstraZeneca said the analysis would be submitted to a peer-reviewed journal for publication.

AstraZeneca said independent safety monitors conducted a specific review of severe blood clotting or severe thrombotic events, based on trial data, including a serious condition known as cerebral venous sinus thrombosis, which is said to be linked to a very small number deaths in Europe among people who received the vaccine. The examination was assisted by an independent neurologist. No increased risk of thrombosis was found in 21,583 participants who received at least one dose of the vaccine, AstraZeneca said.

The U.S. AstraZeneca vaccine trial, which began recruiting volunteers in the U.S., Chile and Peru in August, has been standardized to meet FDA guidelines, measuring the results of two doses four weeks apart. AstraZeneca said that expanding doses – which the UK and other countries have done – could further increase the effectiveness of the vaccine.

The US results in the late stage of the trial provide the best comparison between the AstraZeneca vaccine and competitive shots, which was the first in the US. Clinical trials have shown that the Pfizer and Moderna shots were more than 94% effective against the symptomatic Covid-19.

Oxford-led trials of the AstraZeneca-Oxford vaccine in the UK and Brazil last year have yielded a confusing range of results, ranging from 62% to 90%, depending on the dose size and timing.

Real world vaccination information, highly dependent on the UK. mass rollout, has since shown that a single shot is about 70% effective and very effective in preventing death and hospitalizations. The results suggest that the separation of the two doses by about 12 weeks helped to increase immunity, which after the second shot resulted in about 80% efficacy among people 70 years or older. British researchers said the result was similar to the results of more than 70 of the Pfizer-BioNTech vaccine.

The developing world is counting heavily on the AstraZeneca-Oxford shot, with 3 billion doses promised without profit this year. But public health experts have been concerned about the complex trial results last year and AstraZeneca’s long-standing tension with European officials over the extreme shortage of vaccine delivery targets could damage the reputation of the vaccine permanently.

These factors and errors by AstraZeneca in the public and regulatory communication last year could affect the perception of the vaccine in the US, AstraZeneca experts and analysts said.

At the end of February, the US approved Johnson & Johnson’s Covid-19 vaccine for the US market, bringing a third chance in the country’s large supply chain. That single-dose shot is generally safe and 66.1% effective in protecting people from the development of moderate to severe cases of Covid-19, at least 28 days after vaccination, based on a study of approximately 44,000 volunteers aged 18 and over. years and older.

The U.S. vaccination faced challenges in supply and distribution. But the production and application of shots has picked up over the past few weeks. About 2.5 million people in the US are vaccinated on average daily, compared to about 500,000 in early January.

But many people who want a vaccine can not get it. Stocks of AstraZeneca vaccine can only be distributed in the US before the FDA gets FDA approval.

Last week, the Biden administration planned to send 4 million doses of the AstraZeneca vaccine in stock in the US to Canada in Mexico, as a loan before potential authorization. Officials said no agreement had been reached.

The US said it had 7 million “soluble doses” of the AstraZeneca vaccine. In total, the US ordered 300 million doses of the AstraZeneca-Oxford vaccine, including a 200 million dose contract for the Department of Defense.

The U.S. has been keeping a close eye on vaccine production to reach domestic targets, including by promoting manufacturing partnerships between vaccine manufacturers and promoting financing to accelerate the production of ingredients and supplies.

AstraZeneca has built a global network of manufacturing partners, including the Serum Institute in India, the world’s largest vaccine manufacturer, to achieve its supply targets. Scattered approvals, production shortages and export battles made implementation difficult. AstraZeneca executives have said they are working out supply chain issues and plan to eventually meet announced commitments.

Following reports of blood clots in Europe, regulators there said last week that they would heed a warning at the use guidelines and information sheets for patients for the vaccine, for healthcare providers and people receiving the shot for signs of rare such – called thromboembolic problems – including a severe brain condition that caused a very small number of deaths in people who received the vaccine – and sustained the shot. But government officials stressed that there is no link between the vaccine and coagulation problems, which also occur naturally in the general population and in many cases of Covid-19.

Write to Jenny Strasburg by [email protected]