Russia is ready to conduct clinical trials in Ukraine of a Covid-19 vaccine combining its Sputnik V with a vaccine developed by AstraZeneca together with Oxford University, the head of Russian Direct Investment Fund (RDIF) said on Saturday. Russia’s sovereign RDIF, which is marketing the Sputnik V vaccine abroad, announced in December trials to test a combination of the AstraZeneca vaccine with the Sputnik V shot to see if this can boost the efficacy of the British drugmaker’s vaccine.