A team of Russian scientists last week published the first report on their controversial Covid-19 vaccine. Writing in the Lancet, they reported that volunteers produced a relatively modest amount of antibodies to the coronavirus. In August, President Putin announced with great fanfare that the vaccine - called Sputnik V - “works effectively enough” to be approved. But vaccine developers criticised the announcement, observing that no data had been published on the vaccine. In addition, the Russian scientists had yet to run a large-scale phase 3 trial.
The new paper offers the first chance to take a closer look at Sputnik V. The Russian team published the results of what’s known as a Phase 1/2 trial (where Phase 1 and 2 are combined). The trial was relatively small. Only 40 volunteers received the full vaccine with both kinds of adenoviruses, and no one received a placebo for comparison. Researchers at the Gamaleya Research Institute designed the vaccine using a different virus as a vehicle to deliver coronavirus genes into cells. The vehicle viruses, called adenoviruses, were disabled so that they would only be able to enter cells, but not replicate. Similar vaccines are also being tested by several other teams, including AstraZeneca, CanSino-Bio, and Johnson & Johnson.
The Russian vaccine produced mild symptoms in a number of subjects, the most common of which were fevers and headaches. Other adenovirus-based vaccines have produced similar side-effects. The researchers found that volunteers who got the full vaccine produced antibodies to the coronavirus. They produced immune cells that could respond strongly the coronavirus, too. In their paper, the researchers noted that the vaccine did not produce as many antibodies as AstraZeneca’s vaccine, or the gene-based vaccine made by Moderna. Akiko Iwasaki, an immunologist at Yale University, judged that the vaccine produced “good antibody levels in all volunteers.” But she added that no one yet knows what level of antibodies or immune cells are required to protect people. “It is hard to tell whether the vaccine will be efficacious.”
