MOSCOW: A candidate COVID-19 vaccine known as EpiVacCorona, Russia's second to be registered, proved "100% effective" in early-stage trials, Russian consumer health watchdog Rospotrebnadzor has told local media.

The data, based on Phase I and II trials, were released before the start of a larger Phase III trial which would normally involve thousands of participants and a placebo group as a comparison.

"The effectiveness of the vaccine is made up of its immunological effectiveness and preventative effectiveness," the TASS news agency reported, citing Rospotrebnadzor.

"According to results of the first and second phases of clinical trials, the immunological effectiveness of the EpiVacCorona vaccine is 100%."

The Phase I and II studies tested the safety, reactogenicity and immunogenicity of the potential vaccine in 100 people aged 18-60, according to the state trials register.

Russia began testing EpiVacCorona, which is being developed by Siberia's Vector Institute, in November.

Earlier that month, Moscow said its other approved vaccine, Sputnik V, was 92% effective at protecting people from COVID-19 based on interim results.

Russia has said it can inoculate 60% of its population against COVID-19 this year, and although the Sputnik V vaccine has been readily available in Moscow, the rollout across the country has been slow.

Russian President Vladimir Putin has ordered mass vaccinations to start this week.

EpiVacCorona will be used in mass vaccinations from March, Deputy Prime Minister Tatiana Golikova told the Interfax news agency.

Russia has reported 3,612,800 coronavirus cases, the world's fourth-highest total. Its death toll from the virus stands at 66,623.