On "excellent"
The results of the third phase of the Sputnik-V tests were published in The Lancet
Maria Azarova, Naked Science
The developers of the Russian vaccine against the coronavirus Sputnik-V, led by Denis Logunov, presented to the public the results of the third phase of research on their drug. The work was published yesterday in the peer–reviewed medical journal The Lancet - as well as the results of the second phase, which we wrote about in September.
So, a randomized double-blind placebo-controlled trial took place from September 7 to November 24 last year in 25 medical institutions in Moscow accredited by the Ministry of Health. It involved 21,977 volunteers over the age of 18 who had not previously encountered coronavirus and did not have antibodies to it. First, they were divided into five age groups (18-30 years old, 31-40, 41-50, 51-60 years old and over 60 years old), and then randomly (ratio – 3:1) divided into a vaccine group (16,501 people) and a placebo group (5,476). Sputnik-V was administered at a dose of 0.5 milliliters, and placebo, in turn, represented a buffer composition of the vaccine, but without recombinant adenoviruses. First, the participants from the Sputnik-V group received the first injection with rAd26-S (a vector of recombinant adenovirus type 26), and 21 days later - the second component (rAd5–S, a vector of recombinant adenovirus type 5).
The analysis of the primary results included 19,866 people who were injected with both doses of Sputnik-V itself. Three weeks after the first injection of the vaccine (that is, on the day of administration of the second component of the drug), Covid-19 was detected in 16 (0.1%) of 14,964 vaccinated volunteers and in 62 (1.3%) of 4,902 control group participants by PCR.
Among the most common adverse events are pain at the injection site, headache and fatigue, as well as flu–like symptoms. Serious side effects were found in 45 (0.3%) of the 16,427 participants who received the vaccine, and in 23 (0.4%) of the 5,435 who were given a placebo. However, as scientists note, none of these cases were associated with vaccination.
During the study, four volunteers died: three (less than 0.1%) of the 16,427 who received the vaccine and one (less than 0.1%) of the 5,435 people in the control group. "In the vaccinated group, one death was associated with a fracture of the thoracic vertebra, the other two with Covid–19 (one patient with severe cardiovascular background, who developed symptoms on the fourth day after the first dose, and one patient with endocrinological comorbidities, whose symptoms developed on the fifth day after the first dose). Considering the incubation period, both participants were considered already infected before inclusion in the study, despite the negative result of PCR. In the placebo group, death occurred due to a stroke," the authors of the publication said.
On the 42nd day of the study, 452 volunteers (342 from the vaccine group and 114 from the placebo group) had their blood tested for antibodies. As it turned out, among the participants who received Sputnik-V directly, class G antibodies (they are the last to be produced and retain information about the virus) It was detected in 336 (98%) of 342 samples, the titer averaged 8996. As for the placebo group, IgG was found there in 17 participants (15%) out of 114, the titer was at the level of 30-55. "The 18-30 age group (men and women) had significantly higher levels of antibodies than other age groups," the researchers add.
Levels of class G antibodies in vaccinated and placebo patients / © D. Logunov et al.
Thus, the effectiveness of Sputnik-V was estimated at 91.6% three weeks after the first dose, while in people over 60 years of age this indicator was 91.8%. Since no one in the vaccine group became seriously ill (there were 20 cases in the placebo group), scientists conclude that Sputnik-V protects 100% from severe forms of coronavirus disease.
It is especially worth emphasizing that at any time after the first injection and before the second, the estimated effectiveness of the Russian vaccine was 73.1% – no other drug for the prevention of Covid-19 showed such results. "It is noteworthy that in the vaccinated group, most cases of coronavirus infection occurred before the second dose was administered. The rates of disease occurrence were the same for the vaccine and placebo groups until about 16-18 days after the first dose, after which the early formation of protection led to the fact that the number of cases in the vaccine group grew much slower than in the placebo group," the scientists explain.
"The safety of adenovirus vector vaccines has been widely studied before, and therapeutic drugs based on adenovirus vectors are used in clinical practice. It is known that antigens delivered by the adenovirus vector cause both cellular and humoral immunity after a single immunization. This allows them to be used as an emergency prevention during a pandemic. In addition, the use of two immunizations gives a stable and long–lasting immune response," the developers add.
So, the test results of the Russian vaccine are really impressive. However, there is a risk that the epidemic in Russia will not be stopped in this way. Why – read in our new detailed material.
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