The makers of Russia’s second approved coronavirus vaccine EpiVacCorona are studying third doses to boost recipients' immune response, a senior scientist said Wednesday.
Approved last fall and added to Russia’s mass immunization program last month, EpiVacCorona has come under scrutiny after a group of late-trial study participants claimed that it does not produce an immune response. Early-trial results published in a Russian medical journal this spring disputed that claim, saying that all adults involved in phase one and two trials had developed antibodies.
Alexander Ryzhikov, head of zoonotic infections at the Siberia-based Vektor Institute that developed EpiVacCorona and co-author of the early-trial study, said triple vaccination tests on animals have “confirmed increased and prolonged immunity.”
“First and second-phase clinical trials to introduce triple vaccination [of humans] with this vaccine are currently underway,” Ryzhikov said.
Speaking at an Instagram forum hosted by Russia’s consumer protection watchdog Rospotrebnadzor, which leads national Covid-19 containment efforts, Ryzhikov called third vaccine doses “natural.”