time to explore with esplora

AstraZeneca and Oxford say vaccine shows 70% efficacy

British drugs group AstraZeneca and the University of Oxford said that their vaccine against COVID-19 has shown an average efficacy of 70% in trials. “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,” said Pascal Soriot, AstraZeneca chief executive.

Depending on the dosage, the results ranged between 62% and 90%. As we’re sure you’ve noticed, the 70% average is lower compared to the efficacy of vaccines trialled by their rivals Pfizer/BioNTech and Moderna, both of which have come in above 90%.

Oxford University said that interim analysis from its phase 3 vaccine trial showed that the efficacy is 70%. However, that number was worked out by combining the results of two different dosing regimes, one of which received results of 90% and the other, 62%.

The 90% regime involved a half-dose first and then a full dose of the vaccine a month later. The other showed 62% efficacy when trial participants where given two full doses at least one month apart. The interim analysis was based on 131 infections, among participants who later received the vaccine and those in a control group, who were given an established meningitis shot.

“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,” said Andrew Pollard, director of the Oxford vaccine group. Over 23,000 volunteers took part in the trials, which were conducted in the UK and Brazil, with more data to be collected from around the world in the coming weeks.

Distribution challenges

Firstly, “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” said Soriot.

The company also said that they would immediately be preparing the regulatory submission of the data to health authorities around the world that have a framework in place for condition or early approval.

There are, as one may expect, great challenges before a vaccine can be rolled out. The global battle to secure prospective supplies has raised alarm regarding equitable access, while questions remain over the logistics of mass production, distribution and cost.

AstraZeneca says its vaccine can be stored, transported and handled at normal refrigerated conditions (2-7 degrees Celsius) for at least six months and administered within existing healthcare settings.

It also added that it’s making rapid progress in terms of manufacturing, with a capacity to produce up to three billion doses of the vaccine next year, pending regulatory approval. The company has pledged to distribute the vaccine at no profit, “for the duration of the pandemic.”

By comparison, Moderna said that its vaccine candidate remains stable at the temperate of a standard home refrigerator for up to 30 days. It can also be stored for up to six months at -20 degrees Celsius.

Unlike Moderna, Pfizer and BioNTech’s candidate requires a storage temperature of -70 degrees Celsius and requires special storage equipment and transportation, which may make it difficult for some countries to distribute.