Virus experts are concerned over Russia's plan to roll out its Covid-19 vaccine "Sputnik-V" as its credibility is not guaranteed before full trials. They warned that a partially ineffective shot may encourage the virus to mutate.
Viruses, including the pandemic SARS-CoV-2, are known for their ability to mutate all the time and often has little or no impact on the risk posed to people.
However some scientists are worried that adding "evolutionary pressure" to the pathogen by deploying what might not be a fully protective vaccine could worsen things.
"Less than complete protection could provide a selection pressure that drives the virus to evade what antibody there is, creating strains that then evade all vaccine responses," said Ian Jones, a virology professor at Britain's Reading University.
"In that sense, a poor vaccine is worse than no vaccine," he added.
Developers of Sputnik-V and Russian authorities says that the vaccine is safe and that two months of small scale human trials have shown that it works.
The results of those trials have not been made public however and many Western experts scientists are skeptical. They have warned against its use until all internationally approved testing and regulatory hurdles have passed.
Russia said on Thursday it plans to begin a large-scale efficacy trial of the vaccine in a total of 40,000 people and also begin administering it to people in high-risk groups such as healthcare workers, before the trial has produced any results.
