, Edited by Explained Desk | Pune |
Updated: July 19, 2020 8:28:28 am
Like all the other potential candidates, one being developed in Russia is also far from being ready at this point. Numerous reports on Sunday had claimed that clinical trials for a Russian vaccine had been “successfully” completed. What most of these reports did not specifically mention is that only phase-I of the clinical trials had been completed. Phase-II trials are supposed to start Monday, while there is no clarity over phase-III trials.
What is the candidate vaccine being developed in Russia?
There is only one candidate vaccine being developed in Russia which has reached the human clinical trial stage. That candidate, being developed by the Gamalei National Research Centre for Epidemiology and Microbiology, in partnership with the Russian Defence Ministry, had begun phase-I human trials on June 18, with 18 volunteers from the armed forces having been chosen for administering the vaccine.
A report by the TASS news agency of Russia on July 10 said the phase-I clinical trials will end on July 15, while the phase-II will begin today, that is July 13. “…An in-ward treatment of the first group of volunteers, who were tested for the safety and tolerability of the vaccine, will end on July 15,” the TASS agency quoted Russian Defence Ministry as saying.
What is phase-I in vaccine trials?
Phase-I is where ‘safety and tolerability’ of a vaccine is tested, on a small group of volunteers. The news report said the ministry had claimed that none of the volunteers had reported any complaints, experienced no side-effects, and would be discharged from the hospital soon.
“On Monday, July 13, the second group of volunteers, who are tested for the efficiency and immunogenicity of the vaccine, will be injected with the second component of the vaccine against the Coronavirus,” the agency further said. This round would involve the injection of the vaccine amongst civilian volunteers as well.
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What is the purpose of this round?
This is phase-II, in which ‘efficiency and immunogenicity (generation of immune response)’ is tested. It is in this state that researchers try to see whether the vaccine is triggering the desired immune response in humans, and what could be the suitable doses to generate this response.
And there is a third phase as well?
Usually, yes; vaccine development involves a third phase. In fact, no vaccine for large-scale use has been approved without the third phase of trials till now. A large number of volunteers, usually numbering several thousands, are enrolled for the third phase in which researchers try to ascertain whether the immune response triggered by the vaccine is able to fight the virus in real life situations. This process could take several months.
In the case of Russian candidate vaccine, as with any other candidate, the success of phase-II trials, which could take at least couple of months, is not guaranteed. The success can only be ascertained after the completion of the trials.
So, will there be phase-III if phase-II trials do succeed?
It is not clear as of now whether the Russian candidate vaccine would go through phase-III trials. Usually, that is the case, but recently, considering the current emergency situation, a candidate vaccine developed in China has been approved for use after phase-II trials itself, but it is supposed to be administered only on army personnel as of now. It will depend on the Russian regulatory authorities to decide whether the Russian vaccine would need phase III trials as well.
There are over 150 candidate vaccines for coronavirus being developed all over the world. Nearly half of these are still in pre-clinical stages, meaning they are being tried on animals or are still in early stages of development. About 15 vaccines are in phase-I trials and about ten in phase-II trials. Three vaccines are in phase-III trials.
What happens after phase-III?
Even after the successful completion of phase-III, it usually takes several months before a vaccine is accessible to a general public. Several rounds of regulatory and administrative approvals are required. That is why several scientists, and even WHO officials, have been maintaining that it would be take at least 12-18 months before any Coronavirus vaccine is able to hit the market.
Even then, the vaccine is unlikely to be available for all at one go. Initially, it is expected to be made available only to people who are at higher risk of getting the infection, like healthcare workers. A universal immunisation against Coronavirus can take several years, just like it has been the case with other vaccines.
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