• The University of Oxford, in collaboration with AstraZeneca, announced on November 23 that its COVID-19 vaccine was 70 per cent effective in pivotal trials and could be up to 90 per cent effective.

• Last week, Pfizer and BioNTech said their COVID-19 vaccine candidate is 95 per cent effective, including in adults over 65 years of age. Moderna also said its virus vaccine has an efficacy rate of 94.5 per cent.

• UN Secretary General Antonio Guterres has described the recent breakthroughs towards development of COVID-19 vaccines as a “ray of hope” that needs to reach everyone. 

• AstraZeneca said it will have as many as 200 million doses by the end of 2020, around four times as many as US competitor Pfizer Inc. Seven hundred million doses could be ready globally as soon as the end of the first quarter of 2021.

What are the key points announced by Oxford?

• The interim trial data from its Phase III trials shows its candidate vaccine —  ChAdOx1 nCoV-2019 — is effective at preventing COVID-19 (SARS-CoV-2) and offers a high level of protection.

• These preliminary data indicate that the vaccine is 70.4 per cent effective, with tests on two different dose regimes showing that the vaccine was 90 per cent effective if administered at a half dose and then at a full dose, or 62 per cent effective if administered in two full doses.

• Additional cases are expected to accrue by the time of the final analysis and future analyses will determine the duration of protection. 

• These data also suggest that this half dose and full dose regime could help to prevent transmission of the virus, evidenced by lower rates of asymptomatic infection in the vaccinees, with further information to become available when trial data are next evaluated.

• No serious safety events related to the vaccine have been identified. The vaccine induces strong antibody and T cell immune responses across all age groups, including older adults, and has a good safety profile.

How are the clinical trials progressing?

• The clinical trials, enrolling over 24,000 participants from diverse racial and geographical groups in the UK, Brazil and South Africa, will now continue to final analysis. Further trials are being conducted in the United States, Kenya, Japan and India and the trial team expect to have under 60,000 participants by the end of the year. 

• These trials will provide regulators with further information about the efficacy and safety of the Oxford candidate vaccine, including its ability to both protect against and stop the transmission of COVID-19.

What are the advantages of the Oxford vaccine?

• The result of the Oxford University vaccine compares with the Pfizer and Moderna vaccines, which were recently shown to be 95 per cent and 94.5 per cent effective, respectively. The Oxford University vaccine is comparatively cheaper and easier to store.

• The Oxford vaccine (ChAdOx1 nCoV-19) is made from a virus, which is a weakened version of a common cold virus (adenovirus), that has been genetically changed so that it is impossible for it to grow in humans. 

• Pfizer and Moderna utilise mRNA (messenger RNA) to mimic the surface of the coronavirus and teach the immune system to recognise and neutralise it.

• Adenovirus vaccines have been researched and used extensively for decades and have the significant benefit that they are stable, easily manufactured, transported and stored at domestic fridge temperature (2-8 degrees C). This means they can be easily distributed using existing medical facilities such as doctor’s surgeries and local pharmacies, allowing for the vaccine, if approved, to be deployed very rapidly.

• Its cost to governments works out at just a few dollars a shot, a fraction of the price of the Pfizer and Moderna vaccines using a new, more complex technology. It can also be transported and stored at normal fridge temperatures, which proponents say would make it easier to distribute, especially in poor countries. 

• The faster roll-out means countries that had been drawing up plans to ration vaccines can distribute them more widely, helping to eventually halt the social and economic disruption of a pandemic that has killed 1.4 million people.

• AstraZeneca will now prepare regulatory submission of the data to regulators around the world and seek an emergency use listing from the WHO to speed up availability in poor countries.

Vaccine development in India

• Serum Institute of India (SII), which is conducting clinical trials of AstraZeneca’s ChAdOx1 nCoV-2019 vaccine (which is dubbed ‘Covishield’) candidate in India, welcomed the latest developments.

• While India is in talks with Moderna and Pfizer for their vaccines, the Oxford candidate is the most likely to be deployed in the Indian context due to Serum Institute’s domestic capacity and the vaccine’s feasible temperature requirements.

• Also, the third phase human trial of Covaxin, the much-awaited indigenously developed COVID-19 vaccine, has begun across India. The indigenous vaccine, which is being developed by Bharat Biotech and Indian Council for Medical Research (ICMR), has received approval of the Central Drugs Standard Control Organisation (CDSCO) for initiating the third phase trial. The trial is being conducted at 21 selected medical institutes across the country. 

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