In the long list of vaccine validation steps, this is undoubtedly the most important, the one that unlocks health approval.
The results of clinical trials for the Russian vaccine Sputnik V, announced by Moscow as more than 91% effective against the coronavirus, have just been published by the prestigious scientific journal The Lancet.
This means that they have been validated by its reading committee, and makes it possible to remove the last doubts that existed on this vaccine, which suffered from the lack of transparency in its native country.
The Sputnik V vaccine is therefore 91.6% effective against symptomatic forms of Covid-19, according to these results.
One of the best performing vaccines
“The development of the Sputnik V vaccine has been criticized for its haste, the fact that it has skipped steps and a lack of transparency.
But the results reported here are clear and the scientific principle of this vaccination has been demonstrated, ”said two British specialists, Professors Ian Jones and Polly Roy, in a commentary attached to the Lancet study.
This "means that an additional vaccine can now join the fight to reduce the incidence of Covid-19", insisted these researchers who were not themselves involved in the study.
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These first verified efficacy results corroborate Russia's initial assertions, which were received with suspicion last fall by the international scientific community.
At this stage, they seem to rank Sputnik V among the best performing vaccines, along with those from Pfizer / BioNTech and Moderna (around 95%), which however use a different technology (messenger RNA).
In recent weeks, voices have started to rise in Europe for the European Medicines Agency (EMA) to quickly assess Sputnik V, already used in Russia and in a few countries (including Argentina and Algeria).
What do these results say?
The results published in The Lancet come from the last stage of clinical trials of the vaccine, phase 3, which involves nearly 20,000 participants.
As always in such cases, these results come from the team that developed the vaccine and then conducted the trials, and they were then submitted to other independent scientists for publication.
They show that Sputnik V reduces the risk of contracting a symptomatic form of Covid-19 by 91.6%.
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Participants in the September to November trial all received two doses of the vaccine or placebo three weeks apart.
Each time, this was accompanied by a PCR test.
In the days following the administration of the second dose, a PCR test was only performed in people who developed symptoms.
A total of 16 volunteers out of 14,900 who had received both doses of the vaccine tested positive (0.1%), compared with 62 out of 4,900 who had received the placebo (or 1.3%).
The authors point to a limit, however: insofar as the PCRs were only carried out "when the participants declared to have symptoms of Covid, the analysis of the effectiveness relates only to the symptomatic cases".
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"Further research is needed to determine the efficacy of the vaccine on asymptomatic cases and on transmission" of the disease, The Lancet continued in a statement.
In addition, based on some 2,000 cases of people over 60 years, the study judges that the vaccine seems effective in this age group.
Finally, partial data seem to show that it protects extremely well against moderate to severe forms of the disease.
