The Russia-developed Covid-19 vaccine, Sputnik V, has shown an efficacy of 91% and is safe, said a peer-reviewed study published in the medical journal The Lancet.
In principle, it's possible to use two different vectors because this promises a higher vaccine efficacy. The efficacy of other vector vaccines such as AstraZeneca (76%) and J&J (85.4%), which only use one vector, is much lower than that of the mRNA vaccines by BioNTech-Pfizer (95%) and Moderna (94.1%).

However, logistic wise, SPUTNIK V is friendlier than Pfizer, thus better rollout to the market.