A dosage error and a stroke of luck paved the way for the vaccine produced by the pharmaceutical company AstraZeneca and the University of Oxford to reach 90% effectiveness when administered in half a dose, followed by a dose a month later.
“The reason we had a half dose was a fluke”, Mene Pangalos, head of non-cancer research and development at AstraZeneca, told Reuters.
A larger group that had received two full doses, as originally planned, showed an efficacy rate of 62%, which led to the vaccine having an overall efficacy of 70% including both dosage patterns.
When Astrazeneca was starting its partnership with the University of Oxford in late April, researchers who were administering doses to test volunteers in the UK found that symptoms such as fatigue, headaches and arms were milder than expected.
“So we went back to check and found that we had only given half a dose of the vaccine”, explained Pangalos.
After this discovery, the company decided to continue with the half dose and administer the booster vaccine in a full dose at the scheduled time.
The vaccine against covid-19 developed by the British laboratory AstraZeneca and the University of Oxford has an average effectiveness of 70%, according to a statement released this Monday.
These are interim results from large-scale clinical trials developed in the UK and Brazil, says AstraZeneca.
In relation to the data already available, this vaccine has a lower average efficacy rate than those reported by Pfizer / BioNTech or Moderna, which exceed 90%.
According to the note released this Monday, no hospitalizations or serious cases of the disease were reported among participants in the tests that received the vaccine and there were 131 cases of covid-19 recorded in the interim analysis.
A dosage regimen showed the vaccine to be 90% effective when it was initially administered in half dose, followed by a full dose at least one month apart.
Another dosage regimen showed an efficacy of 62% when administered in two complete doses at least one month apart.
The combined analysis of both dosage regimes results in an average effectiveness of 70%, explains the company, adding that “more data will continue to be accumulated and additional analyzes will be developed, refining the reading of the effectiveness to establish the duration of protection” conferred.
An independent Data Security Monitoring Council determined that the analysis showed protection against the disease 14 days or more after receiving the two doses of the vaccine, says AstraZenca, who underlines that it has seen no serious side effects and that the developed vaccine has been “well tolerated in both dosage regimens”.
“AstraZeneca will now prepare the regulatory sending of data to authorities worldwide so that they have a structure in place for conditional or early approval,” says the laboratory, which will seek to include this vaccine on the World Health Organization’s list of emergency use. Health to accelerate vaccine availability in underdeveloped countries.
In parallel, the full analysis of the interim results is being submitted for publication after peer review, he adds.
Andrew Pollard, chief investigator at the Oxford vaccine testing office, quoted in the statement, says: “These findings show that we have an effective vaccine that will save many lives. Incredibly, we found that one of our dosing regimens may be around 90 % effective and if this dosage regimen is used, more people could be vaccinated with the planned vaccine supply. Today’s announcement is only possible thanks to the many volunteers in our test and the talented and hardworking team of researchers around the world ” .
AstraZeneca’s executive director, Pascal Soriot, considers today as “an important milestone” in the fight against the pandemic, underlining: “The effectiveness and safety of this vaccine confirm that it will be highly effective against covid-19 and will have an immediate impact in this public health emergency “.
“In addition, the simple vaccine supply chain and our nonprofit promise and commitment to broad, equitable and timely access means that it will be affordable and available globally, providing hundreds of millions of doses in approval,” he adds. .
More than 23,000 volunteers participated in the third phase of clinical trials organized by the University of Oxford. Global tests are evaluating participants aged 18 or over from diverse racial groups and geographies, who are healthy or who have stable underlying medical conditions.
Clinical trials are also being conducted in the USA, Japan, Russia, South Africa, Kenya and Latin America with tests planned in other European and Asian countries. In total, the company expects to enroll up to 60,000 participants globally, the note adds.
The company is making rapid progress in production, with a capacity of up to three billion doses of the vaccine in 2021, on an ongoing basis, pending regulatory approval.
The vaccine developed by the British laboratory AstraZeneca and the University of Oxford can be stored, transported and handled under normal refrigeration conditions (2-8 degrees Celsius) for at least six months.
AstraZeneca remains committed to collaborating with governments, multilateral organizations and collaborators worldwide to ensure broad and equitable access to the nonprofit vaccine during the pandemic, he adds.
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