Russian authorities propose trying combination of Sputnik V, AstraZeneca COVID-19 vaccines

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Russian authorities have proposed trying a combination of British-Swedish drugmaker AstraZeneca's COVID-19 vaccine with Sputnik V to boost efficacy.

"Currently, full dose AstraZeneca regimen resulted in 62 percent efficacy. If they go for a new clinical trial, we suggest trying a regimen of combining the AstraZeneca shot with the Sputnik V human adenoviral vector shot to boost efficacy. Combining vaccines may prove important for revaccinations," the Sputnik V official Twitter handle said.

Sputnik V proposal came following reports about AstraZeneca's plan to run an additional global trial to assess the efficacy of lower dosing regimen of its vaccine.

Bloomberg News quoted AstraZeneca CEO Pascal Soriot as saying that the company is looking to conduct an additional global trial instead of adding a trial arm to its ongoing trials in the US after questions were raised over the results from its late-stage study.

In an interim analysis from the phase-3 trial, published earlier this week, AstraZeneca had reported 90 percent vaccine efficacy for a lower dosing regime and 62 percent for two full vaccine doses. However, AstraZeneca-University of Oxford researchers said the lower dosing was not by design but due to the result of an error in the quantity of vaccine put into some vials in the UK arm. This sparked wide criticism, with people calling the error as an embarrassment and the 90 percent efficacy as cherry-picking.

Also Read: Why AstraZeneca-Oxford potential COVID vaccine works better in low dose

It's not the first time, earlier too the official Twitter handle of Russia's Sputnik V vaccine rival to AstraZeneca took potshots at the latter’s vaccine.

"The possible reason for 62 percent efficacy of AstraZeneca’s full dose regimen is that immunity to Chimpanzee adenoviral vector from the first shot makes the second shot ineffective. Sputnik V addresses this issue by using two different human adenoviral vectors for two shots," it says.

Both Sputnik V and AstraZeneca's vaccine use adenovirus as the vector, but they differ as AstraZeneca uses Chimpanzee adenovirus and Sputnik V uses two different strains of human adenovirus. Sputnik V vaccine has claimed 95 percent efficacy.