Oxford & AstraZeneca Covid-19 vaccine up to 90% effective, data shows

Preliminary results from an interim analysis of clinical trials of the ChAdOx1 nCoV-19 candidate show the vaccine is on average 70.4% effective at preventing Covid-19. Data was taken from two dosing regimes, which show that the vaccine is 90% effective when administered at a half dose followed by a full dose, or 62% effective when administered in two full doses.

Data was taken form a total of 131 Covid-19 cases from two clinical trials taking place in the UK and Brazil, including over 23,000 participants.

Importantly, these data indicate that more people could be vaccinated with the University of Oxford’s Covid-19 vaccine, if administered at the dosing level associated with the 90% efficacy.

Professor Andrew Pollard, director of the Oxford Vaccine Group and chief investigator of the Oxford Vaccine Trial, said: “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 regime is used, more people could be vaccinated with planned vaccine supply. Today’s announcement is only possible thanks to the many volunteers in our trial, and the hard working and talented team of researchers based around the world.”

ChAdOx1 nCoV-19 is being developed in collaboration with AstraZeneca and the pharma company has agreed to supply 3 billion doses of the vaccine in 2021. AstraZeneca is ramping up manufacturing capacity to deliver the vaccine doses next year. The vaccine is able to be stored at normal refrigerated conditions for at least six months, the companies state. This means the vaccine is easier to distribute throughout existing healthcare settings.

Co-invented by the University of Oxford’s spin-out company Vaccitech, ChAdOx1 nCoV-19 is a viral vector based on a weakened version of an adenovirus, otherwise known as the common cold virus. It contains genetic material of the SARS-CoV-2 virus spike protein and after vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.

Bill Enright, Vaccitech chief executive officer, said: “The world needs a cost effective, easy to distribute, Covid-19 vaccine that demonstrates safety and works to control the continued spread of this devastating pandemic. Vaccitech is proud to have been a small part of the team, together with Oxford University and AstraZeneca, that moved this vaccine from concept to reality in record time. These latest data give us further confidence in the potential of our ChAdOx technology platform to address other major unmet needs in infectious diseases and cancer.”

The University of Oxford and AstraZeneca will now prepare to submit data to regulatory authorities across the world in order for a potential early approval. AstraZeneca is also seeking an Emergency Use Listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries.

Pascal Soriot, chief executive officer, AstraZeneca, said: “Today marks an important milestone in our fight against the pandemic. This vaccine’s efficacy and safety confirm that it will be highly effective against Covid-19 and will have an immediate impact on this public health emergency. Furthermore, the vaccine’s simple supply chain and our no-profit pledge and commitment to broad, equitable and timely access means it will be affordable and globally available supplying hundreds of millions of doses on approval.”