Phase III of Chinese Convidecia vaccine trials in Russia demonstrates 90.6% immune response - Petrovax
MOSCOW. Aug 11 (Interfax) - Phase III of the Chinese Convidecia coronavirus vaccine trials in Russia demonstrates high efficacy and safety of the medicine, and the immune response reaches 90.6% on the 28th day after vaccination, a representative of the Petrovax company told Interfax on Wednesday.
"In the vaccinated group, all volunteers developed high titers of antibodies to S-protein of the SARS-CoV-2 coronavirus; the immune response reached 90.6% on the 28th day after vaccination. Over the entire monitoring period, the volunteers had a high level of virus-neutralizing antibodies, which proves the vaccine gives lasting protection," the company said.
Phase III of the local clinical trials conducted in Russia proved high efficacy and safety of the vaccine, Petrovax said.
"The information was given in the final report submitted by the Petrovax company to the Russian Health Ministry in early August. The trial shows that one shot of the vaccine evokes a pronounced immune response, with good tolerance and a high safety profile," the company said.
"There were no deaths in the course of trials. There were no adverse side effects in the vaccinated group either," Petrovax said.
"Not a single case of early termination of trials because of adverse effects has been registered," it said.
General post-vaccination reactions were registered in 26.9% of volunteers from the vaccinated group and 10.5% of volunteers from the placebo group, the company said.
"In the vaccinated group, the most frequent reactions were fever (20.2%), headache (5.9%), fatigue (5.4%), muscle ache (4.8%) and joint pain (1.9%). In most cases, 21% of volunteers inoculated with Convidecia, exhibited light systemic post-vaccination reactions. Medium reactions were demonstrated by 4.6% of subjects," it said.
"General and local post-vaccination reactions, as well as undesirable effects were gone in most volunteers in both groups within seven days after he vaccination. Local post-vaccination reactions were registered in 21.8% of subjects," Petrovax said.
The trial also assessed the influence of existent adenoviral vector immunity on the vaccine efficacy, it said.
"It appeared that the share of volunteers with a high level of adenovirus antibodies grew after vaccination. In other words, the vaccine evoked immune response to the carrier virus. Meanwhile, the amount of adenovirus antibodies available at the moment of vaccination had absolutely no effect on the level of seroconversion, the main indicator of immunity to SARS-CoV-2. This information indicates that the efficiency of vaccination does not depend on the existent adenovirus immunity, while stimulation of the immune response to adenovirus by vaccination will not influence the efficiency of re-administering of the same vaccine," the company said.
The company submitted intermediate analysis results to the Russian Health Ministry in December 2020 for considering the vaccine's registration, the press service quoted Petrovax Pharm President Mikhail Tsyferov as saying.
"The final data was received today. We have prepared necessary facilities to make the vaccine at our enterprise in the Moscow region," Tsyferov said.
Convidecia is a recombinant vaccine based on a human type 5 adenoviral vector carrying the S-protein of the SARS-CoV-2 virus, developed by CanSino Biologics Inc. (CanSinoBIO, HK6185), a leading immunobiological company in China.