A group of international scientists questioned results from a study of Russia's fast-moving coronavirus vaccine that were published in the Lancet medical journal, saying some of the findings appeared improbable.
The researchers flagged concerns over seemingly identical levels of antibodies in a number of study participants who were inoculated with the experimental vaccine. This and other patterns in the data present "several different points of concern," according to an open letter written by Temple University professor Enrico Bucci and signed by more than a dozen other scientists.
The Lancet published results of the early stage trial last week, offering the first look at the Russian study to be vetted by outside experts. A move by the government to approve the shot for use based on the initial results had drawn widespread skepticism, since vaccines aren't normally cleared before broad assessments of their efficacy and safety.
"We have shared the letter directly with the authors and encouraged them to engage in the scientific discussion," the Lancet said in a statement.
The Gamaleya Research Institute of Epidemiology and Microbiology and the Russian Direct Investment Fund, which are developing the vaccine, said the data was not manipulated.
"The published data is reliable and accurate and has been studied by five reviewers of the Lancet," Gamaleya Deputy Director Denis Logunov said, according to a statement provided by RDIF. "A full-length clinical protocol was provided to the editorial office of the journal."
The latest international doubts hasn't dampened Russia's enthusiasm for the vaccine, dubbed Sputnik V in a nod to the world's first artificial satellite that was launched by the Soviet Union in 1957.
The Russian Direct Investment Fund will sell 32 million doses of Sputnik V to Mexico, with deliveries starting in November, the sovereign wealth fund said in a statement Wednesday.
Phase 3 testing that will study 40,000 volunteers over 180 days began Wednesday, the Health Ministry said in a statement. The first results from the study may be published in October or November, according to the RDIF.
Russia is sticking with a plan to begin vaccinating health workers next month, even as another candidate in late stage testing suffered a setback. AstraZeneca Plc stopped giving shots this week of its experimental coronavirus vaccine after a person participating in one of the company's studies got sick.
"Sputnik is a human vaccine, while AstroZeneca's is a monkey vaccine," Kremlin spokesman Dmitry Peskov said Wednesday on a conference call. "Our scientists believe that the human vaccine is much more reliable in this regard."
