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The Oxford/AstraZeneca COVID-19 vaccine: where are we now?

After the UK reached its goal of 15 million first doses of the vaccine for COVID-19 administered by Monday 15th February 2021, there is increasing optimism about national and international efforts to fight the pandemic. 

Sunday 14th February marked the day where this target was reached, with every individual in the top four priority groups having been offered the vaccine, a day before the deadline for reaching the Government’s UK vaccination goal. Alongside this progress, there are new stories coming out almost every day about developments in the national and global vaccination effort. Here, I will summarise some of the recent key stories about the Oxford/AstraZeneca vaccine.

Most recently, the WHO yesterday approved two versions of the Oxford/AstraZeneca vaccine for emergency use globally, with the only other vaccine being approved for this use so far being the Pfizer/BioNTech vaccine (which was approved for emergency use on the 31st December 2020). These Oxford vaccine versions are produced by SK Bioscience (a South Korean biopharmaceutical business) and the Serum Institute of India, which is “the world’s largest vaccine manufacturer by number of doses produced and sold globally”. This means that the vaccine can now be distributed to and used in countries that previously had none available to them. The Oxford/AstraZeneca vaccine is particularly useful for global distribution due to the less tough storage requirements of the Oxford vaccine compared to others available on the market, providing a key next step in the pursuit of widespread vaccination.

This comes after the WHO issued interim recommendations for the use of the Oxford/AstraZeneca vaccine against COVID-19 on the 10th February 2021, based on advice from the Strategic Advisory Group of Experts (SAGE). The WHO advises that the vaccine “has an efficacy of 63.09%…against symptomatic SARS-CoV-2 infection”, which is based on the data from “participants in trials in the United Kingdom, Brazil, and South Africa who received 2 standard doses”. They go on to recommend that “all vaccinated individuals receive two doses”, with a recommended interval of 8 to 12 weeks based on the observation of increased efficacy with a longer gap between doses. Furthermore, they report that the vaccine can be used on anyone aged 18 and over. This may help to ease concerns expressed by other countries such as Germany, whose vaccine committee commented in January 2021 that there was “insufficient data” for the efficacy of the Oxford/AstraZeneca vaccine in people aged 65 or older.

Late last week it was announced that trials testing the efficacy of the Oxford/AstraZeneca vaccine in younger age groups, specifically 6 to 17 year olds, will be conducted, led by the University of Oxford and held at sites in Oxford, Southampton, London, and Bristol. In an article addressing frequently asked questions about the children’s study, the research team stated that they will “assess the safety and immune responses in children and young adults”, with up to 300 children being enrolled in the study (150 aged 6-11 years old, and 150 aged 12-17 years old). It will be “the first trial of a COVID-19 vaccine in this age group (6-17 years). Some trials have begun in teenagers (16/17 years). None of them are yet licensed for younger children”. The children will be given two doses of either the Oxford/AstraZeneca vaccine or the vaccine for Meningitis B (the control group). It is hoped that promising results in these clinical trials will pave the way forward for the vaccination of under 18s.

There was also controversy within the media when South Africa suspended its use of the Oxford/AstraZeneca vaccine due to data suggesting that it was less effective against the South Africa variant of COVID-19, and it is reported that they are giving away 1 million doses of the Oxford/AstraZeneca vaccine to other African countries. The vaccine only demonstrated “minimal protection” against the South African variant, which is thought to cause mild to moderate infection but is more easily transmissible. There is uncertainty over the effectiveness of the vaccine against severe disease and hospitalisation due to studies containing mostly young adults as well, as they tend not to suffer from as severe a COVID-19 infection as older people.

South Africa has opted to offer their health workers the Pfizer/BioNTech vaccine developed by Johnson and Johnson instead, which has been shown by Xie and colleagues (2021) to still be effective against three of the key spike mutations from the new UK and South Africa variants of COVID-19. A cautious approach is needed though, as the study used engineered viruses that did not replicate all of the mutations of the real UK or South Africa variants, so further research may be needed.

There is promising data around updating the Oxford/AstraZeneca vaccine to target new variants of the novel coronavirus, which is especially important with the recent discovery of another new variant by researchers at the University of Edinburgh, which has reportedly been in circulation since 15th December 2020. A modified version of the Oxford/AstraZeneca vaccine is expected to be ready by autumn for new variants such as the South Africa variant.

Image source: Alachua County on Flickr