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An interim analysis of data from the phase III trial of the Russian vaccine Sputnik V against covid-19 suggests that a two-dose regimen offers 91.6 percent efficacy against symptomatic disease; a protection that in people over 60 years is very similar and rises to 91.8 percent.
The scientific journal The Lancet published on Tuesday the preliminary results of this vaccine, which are based on the analysis of data from almost 20,000 participants, of which three quarters received the vaccine and a quarter a placebo.
The trial included 2,144 participants over the age of 60 and the efficacy of the vaccine was 91.8 percent in this group: the vaccine was well tolerated and safety data from 1,369 of these older adults revealed that the most common adverse effects were flu symptoms and local reaction, the document says.
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These effects coincide with the majority of adverse events reported in the other groups, which were also generally mild; the severe ones (those that required hospital admission) were scarce in both the placebo group (0.4 percent) and the vaccine group (0.2 percent).
Four deaths were reported in the trial, none of which were considered related to the vaccine.
In a comment associated with this research, Ian Jones, from the University of Reading, and Polly Roy, from the London School of Hygiene & Tropical Medicine (who were not involved in the study), stated: “The development of the Sputnik V vaccine has been criticized for improper haste, shortcuts or lack of transparency, but the result presented here is clear and the scientific principle of vaccination is demonstrated. ”
“This means that another vaccine can now join the fight to reduce the incidence of covid-19,” they say.
(You may be interested: Don’t believe the myths: vaccines are safe and mitigate the virus)
More details
“Our interim analysis of the phase III randomized controlled trial has shown high efficacy, immunogenicity, and a good tolerability profile in participants aged 18 years and older,” says Inna V Dolzhikova, from the Gamaleya National Center for Research in Epidemiology and Microbiology ( Russia).
Within 21 days of receiving the first dose (the day of dose 2), 16 cases of symptomatic covid-19 were confirmed in the vaccine group (0.1 percent) and 62 cases (1.3 percent) in the placebo group, which equates to an efficacy of 91.6 percent, the study summarizes.
The vaccine induced a robust humoral response (antibody response) and a cellular immune response (T-cell response) with data from 342 and 44 participants, respectively.
It should be clarified that This efficacy analysis only includes symptomatic cases, so more research is needed to understand the efficacy of the vaccine in asymptomatic patients. In addition, the mean follow-up was 48 days from the first dose, so the study cannot assess the full duration of protection.
(See: Colombia confirms two cases in Leticia of the Brazilian variant)
As part of their secondary analyzes, the authors explored efficacy against moderate or severe COVID-19. At 21 days after the first dose, there were no cases or severe in the vaccine group and 20 cases in the placebo group, which is equivalent to 100 percent efficacy against severe forms of this disease.
Although the study was not designed to evaluate the efficacy of a single dose regimen, the results point to the early onset of a partially protective effect between 16 and 18 days after single dose immunization; the team recently received approval to investigate the efficacy of a single dose.
The authors also point to the need for more research to study the vaccine in adolescents and children and in pregnant women. The trial is ongoing and aims to include a total of 40,000 participants.
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The vaccine
These first verified results corroborate Russia’s initial claims, received with mistrust at the end of last year by the international scientific community and thus Sputnik V would thus rank among the most effective vaccines, alongside those of Pfizer / BioNTech and Moderna (around 95 percent).
Gam-COVID-Vac or Sputnik V, as it is known, is a two-part vaccine that includes two adenovirus vectors -rAd26-S and rAd5-S- that have been modified to express the S protein of Sars-CoV-2. Adenoviruses are also weakened so that they cannot replicate in human cells and cannot cause disease.
This technique has been used before and its safety has been confirmed in several clinical studies, recalls the journal in a note. In this trial, participants received a dose of rAd26-S, followed by a booster dose of rAd5-S 21 days later.
(In addition: The data that the ‘My Vaccine’ portal will have, available in a week)
According to those responsible, Using a different adenovirus vector for the booster vaccination can help create a more powerful immune response, as it minimizes the risk of the immune system developing resistance to the initial vector.
The Russian vaccine has been licensed and is applied in addition to in Russia in 14 other countries, including Hungary, Algeria, Serbia, Argentina, Bolivia, Venezuela, Paraguay, Turkmenistan, Belarus, Kazakhstan, United Arab Emirates and Iran. And the Czech Republic, Mexico and Sri Lanka have been interested in her.
Finally, it is worth saying that this vaccine does not require deep-freezing technology for storage.
HEALTH UNIT
