The specialists of the Vector Center of Rospotrebnadzor, who created EpiVacCorona vaccine, said that the conclusions of St. Petersburg researchers about the negative activity of the drug are premature.
As a representative of the Center told Interfax, such results may be due to an insufficient sample size, as well as to the fact that the vaccine is usually chosen by elderly people and patients with chronic diseases who want to minimize possible side effects.
According to the study, the effectiveness of Sputnik against the delta strain of COVID-19 was 58%, Sputnik Lite – 50%, CoviVac – 38%, and EpiVacCorona – minus 40%. According to the explanations provided by the Institute of Interdisciplinary Medical Research of the European University in St. Petersburg, it was impossible to track the unvaccinated and asymptomatic cases, so all calculations are “slightly biased towards underestimating the effectiveness”, i. e., the actual effectiveness of drugs is higher than the findings of the study showed. The negative activity of EpiVacCorona means that the risk of disease for those vaccinated with this vaccine is higher than for the unvaccinated.
“The results presented in the preprint do not provide the statistical significance required to draw conclusions not only about the effectiveness of vaccination with Epivaccorona, but also with other vaccines,” the Vector Center stressed.
The creators of the vaccine believe that the error probably lies in the “extremely low power of the study due to the small coverage of the population with vaccination in the absence of a justification for the sample size.”
The study was based on two samples. One of them included 1,198 people with symptoms of coronavirus and a confirmed diagnosis, who underwent CT scans at the Berezin Medical Institute from October 6 to 14, 2021. The second sample included 2,247 residents of St. Petersburg, including fully vaccinated individuals. They were interviewed on the same days on the presence of antibodies; the group included 28 people vaccinated with EpiVacCorona.
Vector expects an order from the Ministry of Health for the production of EpiVacCorona in February. As Vedomosti reported earlier, the Russian Ministry of Health has suspended the procurement and supply of EpiVacCorona vaccine.