The Russian health ministry's ethical committee has declined to approve clinical trials in Russia combining a British shot from AstraZeneca and Oxford University with Russia's Sputnik V vaccine, an AstraZeneca official told Reuters on Friday. Irina Panarina, AstraZeneca general director in Russia and Eurasia, said the decision did not mean that the trials would never be approved or were definitively prohibited. Before the committee's decision she said that AstraZeneca had received questions about the trials from the health ministry and was now preparing a response to them, which would be sent next week. Human trials of a COVID-19 vaccine combining a shot from AstraZeneca and Britain's Oxford University with Russia's Sputnik V vaccine in a heterologous prime-boost regimen were approved in Azerbaijan, the United Arab Emirates and Belarus, said Panarina. Russia's health ministry did not immediately reply to a Reuters request for comment. Both vaccines, from AstraZeneca and Oxford university and Sputnik V, involve two doses. Sputnik, however, uses different adenoviral vectors for its two shots. AstraZeneca's vaccine uses a modified chimpanzee adenovirus vector. The idea for the trials is that participants first receive the AstraZeneca vaccine and then the first Sputnik V shot 29 days later. —Reuters Staff Source