Only phase-I trial of Russian Covid-19 vaccine completed, enters phase-II

After completing the first phase of the trial to prove its safety, the much talked about Russian Covid-19 vaccine will have to undergo the second phase of the trial to demonstrate its efficacy to fight the novel coronavirus.

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If the phase-II turns out to be a success too, the trial would ideally move into phase-III in which the vaccine’s effectiveness needs to be shown on a large number of volunteers before the vaccine hits the market.

Going by the Russian regulatory records maintained at the US National Library of Medicine under the National Institutes of Health, the Russian researchers have obtained approval for phase-I and phase-II trials.

Since the follow-up period for the first phase of the vaccine is 180 days, it is unlikely that a commercial vaccine would hit the market anytime in near future contrary to the reports in a section of the media.

Developed by the Gamaleya Research Institute of Epidemiology and Microbiology under the Health Ministry of the Russian Federation, the vaccine is a cocktail of two genetically engineered adenoviruses – Ad 26 (used as prime) and Ad 5 (boost) both carrying the SARS-CoV-2 spike gene. Since they carry the gene responsible for making the viral spike protein they are likely to elicit the major protective immune responses against the pandemic virus.

Two different formulations of the vaccine have been made. One is a freeze-dried form for thermal stability while the second one is a solution formulation.

In the first phase, the safety of the two components of the vaccine was determined on 38 healthy volunteers split into two groups whereas, in phase-II, the vaccine’s efficacy would be determined as per the protocol that Russian researchers had shared with the World Health Organisation.

“The tested vaccine has been proved safe for the patients, which is the key result of this clinical study. The first group of volunteers will be discharged from hospital on July 15 and the second group will follow on July 20. The participants will remain under observation for the next six months to monitor if they develop any health issues due to the vaccination in the long run,” Yelena Smolyarchuk, who heads the Sechenov University Centre for Expert Evaluation of Medicinal Products said in a statement.

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The university conducted the trial under the supervision of the Ministry of Defence. Russian news agency TASS reported that the first group of volunteers is from the armed forces.

Typically vaccine development involves three phases. In the first two phases, the safety and efficacy of the vaccine are checked on a small number of volunteers, while in the third phase, the efficacy (immunogenicity) is checked on a large number of volunteers. It is not clear at the moment, whether the standard protocol would be followed or is there a fast-tracking to bring the “viral vector vaccine” quickly to the market.

"Russia has fast-tracked a vaccine which has been successful in its early phases. They have fast-tracked its development," Dr Balram Bhargava, director general, Indian Council of Medical Research said here on Tuesday.

The Russian vaccine is one of the 23 vaccines – listed by the WHO – that are under clinical evaluation. In addition, there are 140 candidate vaccines that are at a preclinical stage.