The United Kingdom's Medicines and Healthcare products Regulatory Agency (MHRA) approved a two full-dose regime of the Oxford-AstraZeneca AZD1222 COVID-19 vaccine which will be rolled out by January 4 in the country to tackle the ongoing coronavirus pandemic.
The approval of this frontrunner vaccine by the MHRA comes at a time when a new, more infectious variant of the coronavirus is seen to have emerged from the country. Several countries across the world including India have suspended air travel with the UK to control the spread of this B.1.1.7 variant.
Oxford University's Jenner institute developed this adenoviral vaccine taken from chimpanzees which is going to be mass produced by Swedish pharmaceutical giant AstraZeneca. The vaccine was shrouded in controversies after its Phase 3 interim results showed that in UK two different doses were administered to participants. While the vaccines two full-doses regime showed 62% efficacy, its one half and one full-dose regime showed 90% efficacy. The UK authorities have however, approved only the two-full doses regime which is likely to begin distribution from January 4.
The chimpanzee adenovirus acts as a vector to transfer the DNA of the coronavirus spike protein to the human body. Once injected it then facilitates the creation of the spike protein which is identified as a pathogen by the human body. The human body then starts creating antibodies to fight against this induced pathogen.
Unpublished data accessed by BBC reveals that the efficacy of the two full-doses regime increases if the time period between the first and the second dose is prolonged. Currently, the second dose is administered 28 days after the first one.
Despite its actual effectiveness still being questioned, the approval of this vaccine will bring cheer to several low- and middle-income countries including India. The AZD1222 vaccine can be stabilised at temperatures used by routine cold chain, uses technology that has been employed for vaccines earlier, and is priced moderately giving it an advantage over both the Moderna and Pfizer mRNA vaccines that require cold chains at very low temperatures and are expensive.
As part of the World Health Organisation's COVAX- ACT Accelerator, the vaccine will also be equitably distributed across all countries.
This approval also raises hopes for India. The Indian drug regulator refused to give Serum Institute of India, who is producing the vaccine in India, emergency use authorization as it felt that the data provided by the vaccine maker was insufficient. It also requested the company to provide details from the UK. As the vaccine has now been approved in the UK, the decision of the Indian Subject Expert Committee is now awaited.