New Delhi, Jan 4 : With the Drug Controller General of India (DCGI) approving Serum Institute of India's 'Covishield' vaccine and Bharat Biotech's 'Covaxin' for emergency use, paving way for their roll-out and administration to millions, Russian Sputnik V vaccine makers have said that they are working with AstraZeneca (AZ) to take the efficacy of AZ vaccine to over 90 per cent. In a tweet, Sputnik V said: "As Indian regulator recommends for approval full-dose regimen of AstraZeneca's vaccine with efficacy of 62.1 per cent based on phase 3 clinical data. Sputnik V is working on clinical trials with AZ to increase the efficacy of AZ vaccine to over 90 per cent". AstraZeneca is currently working with the Russians on the combination of their vaccine's vector with that from Sputnik V (showing 91.4 per cent efficacy as per Phase 3 final control point recorded last month), precisely to see if that could help boost its vaccine's efficacy to over 90 per cent as well. While both vaccines use adenoviral vector technology, the AstraZeneca vaccine is based on a chimpanzee adenovirus (which is not the most popular technology among the vaccinated as recently conducted polls indicated that, given a choice, consumers prefer other technologies), the Sputnik V vaccine is based on a human adenovirus. Unlike AstraZeneca, which uses one and the same component for both inoculations, the Russian vaccine uses two different ones in two separate inoculations. Using the latter approach could prove more efficient in achieving a longer-lasting immune response. Covishield and Covaxin have to be administered in two doses and can be stored at 2-8 degrees Celsius. The Drugs Controller General of India has also granted permission to Cadila healthcare for phase 3 clinical trial in India. The vaccine will be first offered to one crore healthcare workers, along with two crore frontline and essential workers and 27 crore elderly, mostly above the age of 50 years with co-morbidities. India will produce about 300 million doses of the Russian Sputnik V coronavirus vaccine in 2021, Head of the Russian Direct Investment Fund (RDIF), Kirill Dmitriev, said in an interview with Rossiya 24 TV channel last month. "In India, we have agreements with four large manufacturers. India will produce about 300 million doses or more of the vaccine for us next year," Russian news agency Tass quoted him as saying. In September 2020, Dr. Reddy's Laboratories and RDIF entered into a partnership to conduct clinical trials of the Sputnik V vaccine and the rights for distribution of the first 100 million doses in India. Dr. Reddys and RDIF announced in December that they have commenced adaptive Phase 2 and 3 clinical trials for Sputnik V vaccine in India for Covid-19 after receiving the necessary clearance from the Central Drugs Laboratory, Kasauli. On August 11, 2020, the Sputnik V vaccine developed by the Gamaleya National Research Institute of Epidemiology and Microbiology was registered by the Ministry of Health of Russia and became the world's first registered vaccine against Covid-19 based on the human adenoviral vector platform. /IANS