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Infectious Diseases

14 July 2020

Covid-19 vaccine and Russia: Only first part of trial completed, and still a long way to go

It has been reported that Russia has "completed clinical trials" of its Covid-19 vaccine – but only the first phase has been completed - there is still a long way to go.

  • Several reports have announced that Russia’s vaccine candidate has completed clinical trials
  • However, this only phase 1, which involves just a small group of people
  • Clinical trials usually consist of three phases to determine safety and efficacy 

As the world scrambles to find a vaccine for the contagious Covid-19 disease caused by the novel coronavirus, any headline proclaiming progress will make us feel more positive in a time of uncertainty.

On 13 July 2020, it was reported that Russia became the first country to complete clinical trials of a Covid-19 vaccine candidate after Sechenov University announced that it had "concluded the study".

According to the Sechenov University Center For Clinical Research on Medications chief researcher Elena Smolyarchuk, human trials were now “completed” after 20 patients volunteered and were quarantined for 28 days.

But does this mean the vaccine is now ready for distribution? 

Despite numerous reports about completed clinical trials, it wasn’t specified that only phase I of the clinical trials had been completed. This means that the safety and tolerability of the vaccine was tested on a small group of volunteers – in the case of this vaccine candidate, only 20 patients.

On a positive note, however, none of the volunteers experienced negative side-effects and were ready to be released from hospital, where they had been quarantined.

Phases explained

Vaccine trials involve three phases, explained Dr Wilbur Chen, an adult infectious disease expert at the University of Maryland's Center for Vaccine Development and Global Health in a previous Health24 article:

  • Phase I trials test whether the vaccine is safe, and usually last about six months.
  • Phase II trials examine how well the vaccine works in creating an immune response within volunteers, and last up to a year.
  • Phase III trials track the effectiveness of the vaccine in preventing infection in people exposed to the pathogen. This phase could take three years or more, and depends on the virus remaining active long enough.

Entering phase two

On Monday 13 July 2020, TASS Russian News Agency reported that the second clinical phase would begin, where the second component of the vaccine would be administered to a slightly larger group of people.

During this phase, the efficiency and the generation of an immune response from the vaccine will be tested. Where the first phase simply determined if the vaccine is safe, this phase will test if the immune system delivers the desired response to make recipients immune against SARS-CoV-2.

What happens then?

After phase two, the vaccine moves into the third phase, to determine its safety and efficacy in a much larger group – usually consisting of several thousand people – to determine if the vaccine can be rolled out en masse.

Currently, it’s not clear if the Russian vaccine will enter phase three, as many vaccine candidates have been fast-tracked in the current medical emergency.

But even when a vaccine has completed phase three of a clinical trial, it doesn’t mean that it is ready to be distributed, as there are many processes required to obtain regulatory approvals from different nations.

And once the vaccine is finally produced, it may be administered to those most vulnerable to the disease first as part of a phased approach.

Vaccine development – where are we now?

The Russian vaccine is not the only candidate on the market. Over 150 vaccine candidates are being developed, with three of them already in phase three trials, including the vaccine from AstraZeneca and the University of Oxford, which is also being trialled in South Africa and may be ready for emergencies by October.

READ SA's vaccine trial: Covid-19 science is moving fast, what about safety?

READ | Why vaccines need to be tried and tested in different populations across the world

Image credit: Arek Socha from Pixabay