COVID-19 Resource Center

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Press Release

Disclosures: Healio could not confirm relevant financial disclosures for Pollard at the time of publication.
November 23, 2020
2 min read

COVID-19 vaccine developed by AstraZeneca, Oxford is up to 90% efficacious


Press Release

Disclosures: Healio could not confirm relevant financial disclosures for Pollard at the time of publication.
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An interim analysis of clinical trial results in the United Kingdom and Brazil showed that a COVID-19 vaccine candidate codeveloped by AstraZeneca and Oxford University had an average efficacy of 70% with no significant safety concerns.

One dosing regimen was 90% efficacious when the vaccine, AZD1222, was given as a half dose, followed by a full dose at least 1 month apart. The other dosing regimen was 62% efficacious when given as two full doses at least 1 month apart, resulting in an average efficacy of 70% between the two regimens, AstraZeneca reported. The company said there have been no serious safety events related to the vaccine.

COVID Vaccine
AstraZeneca hopes their COVID-19 vaccine candidate can be granted accelerated availability to low-income countries after showing a pooled efficacy rate of 70% in clinical trials.
Credit: Adobe Stock

The pooled data were from the COV002 phase 2/3 trial in the U.K. and COV003 phase 3 trial in Brazil. According to a press release, the reported results from the two trials involved 11,636 trial participants aged 18 years or older from diverse racial and geographic groups. Participants received either a half-dose/full-dose regimen or a regimen of two full doses of AZD1222 or a meningococcal conjugate vaccine called MenACWY or saline.

The company reported that participants are a mix of healthy individuals and those with “stable” underlying conditions.

“These findings show that we have an effective vaccine that will save many lives. Excitingly, we’ve found that one of our dosing regimens may be around 90% effective, and if this dosing regimen is used, more people could be vaccinated with planned vaccine supply,” Andrew J. Pollard, FRCPCH, PhD, FMedSci, professor of pediatric infection and immunity at the University of Oxford and chief investigator of the Oxford Vaccine Trial, said in the release.

Based on the data, AtraZeneca said it will “immediately” prepare regulatory submissions in countries that have a framework in place for conditional or early approval and will seek an emergency use listing from WHO for an accelerated pathway to make the vaccine available in low-income countries.

According to AstraZeneca, the vaccine is stable at normal refrigerated temperatures for at least 6 months, in contrast to other COVID-19 vaccines in development that need to be transported at extremely low temperatures. The company said it has the capacity to produce up to 3 billion doses in 2021.

It was the third consecutive Monday that a COVID-19 vaccine program announced good news. Pfizer and BioNTech have already submitted data to the FDA for an emergency use authorization after data showed their messenger RNA (mRNA)-based vaccine candidate was 95% efficacious. Another mRNA-based vaccine candidate codeveloped by Moderna Inc. and the NIH also was shown to be around 95% efficacious.

In contrast to those mRNA-based vaccines, AZD1222 is a chimpanzee adenovirus-vectored vaccine expressing the SARS-CoV-2 spike protein, which primes the immune system to attack SARS-CoV-2.

AstraZeneca said it plans to compile and analyze more data to refine the efficacy profile and establish the duration of protection, according to the press release. Additional trials of AZD1222 are underway in Japan, Kenya, Latin America, Russia, South Africa and the United States, with other planned trials in other European and Asian countries.