An interim analysis of data from the phase III covid vaccine trial – 19 from Russia (Sputnik V) suggests that a two-dose regimen offers an efficacy of 91 .6% against symptomatic disease; a protection that in older than 60 years is very similar and rises to 91. 8%.
Preliminary results, published in “The Lancet”, are based on analysis of data from almost 20, 000 participants, of which three quarters parts received the vaccine and a quarter received placebo.
The trial included 2. 144 participants older than 60 years and the efficacy of the vaccine was 91, 8% in this group: the vaccine was well tolerated and the safety data of 1. 369 of these older adults revealed that the most common adverse effects were flu symptoms and local reaction.
These coincide with the majority of adverse effects reported in the other groups, which in general were also mild; the severe ones (those that required hospital admission) were scarce in both the placebo group (0.4%) and the vaccine group (0.2%).
None, they say the authors considered it associated with vaccination; Four deaths were reported in the trial, none of which were considered vaccine-related.
In a comment associated with this research, Ian Jones of the University of Reading, and Polly Roy, from the London School of Hygiene & Tropical Medicine (who were not involved in the study), state: 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 join now to the fight to reduce the incidence of covid – 19 “, he assures.
Gam-COVID-Vac or Sputnik V is a two-part vaccine that includes two adenovirus vectors -rAd 26 – S and rAd5-S- that have been modified to express the SARS-CoV-2 protein S.
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 rAd 26 – S, followed by a booster dose of rAd5-S 21 days later.
According to those responsible, the use of a different adenovirus vector for the vaccination of Boost can help create a more powerful immune response by minimizing the risk of the immune system developing resistance to the initial vector.
“Our interim analysis of the randomized trial and controlled in phase III has shown great efficacy, immunogenicity and a good tolerability profile in participants of 18 years or more ”, he states. Inna V Dolzhikova, from the Gamaleya National Center for Research in Epidemiology and Microbiology (Russia) .
At 21 days after receiving the first dose (the day of dose 2), 16 covid cases – 19 symptomatic in the vaccine group (0.1%) and 62 cases (1.3%) in the placebo group, which equates to an efficacy of 91, 6%, summarizes the study.
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.
This efficacy analysis only includes symptomatic cases, so further 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.
As part of their secondary analyzes, the authors ex explored efficacy against covid – 19 moderate or severe. At 21 days from the first dose, there was no case of covid – 19 moderate or severe in the vaccine group and 20 cases in the placebo group, which is equivalent to an efficacy of 100% against covid – 19 moderate or severe.
Although the study did not designed to evaluate the efficacy of a single dose regimen, the results point to the early appearance of a partially protective effect among the 16 and 18 days after immunization with a single dose; the team recently received approval to investigate the efficacy of a single dose.
The authors further note the need for further research to study the vaccine in adolescents and children and pregnant women. The trial is ongoing and aims to include a total of 40, 000 participants.
The Russian vaccine has been authorized in addition to Russia in other 14 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 it.
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