Russia vaccine roll-out plan prompts virus mutation worries

FILE PHOTO: A handout photo provided by the Russian Direct Investment Fund (RDIF) shows samples of a vaccine against the coronavirus disease (COVID-19) developed by the Gamaleya Research Institute of Epidemiology and Microbiology, in Moscow, Russia August 6, 2020. Picture taken August 6, 2020. The Russian Direct Investment Fund (RDIF)/Handout via REUTERS

LONDON (Reuters) - 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.