Russia vaccine roll-out plan prompts coronavirus mutation worries

Russia's plan to roll-out its "Sputnik-V" Covid-19 vaccine even before full trials show how well it works is prompting concern among virus experts, who warn a partially effective shot may encourage the novel coronavirus to mutate.Viruses, including the pandemic SARS-CoV-2, are known for their ability to mutate all the time - and often this has little or no impact on the risk posed to people.