Russian scientists Denis.Y. Logunov, Inna.V. Dolzhikova and Dmitry. V. Shcheblyakovv published a note in the 'online first' section of the international medical journal 'The Lancet', to address issues associated with data discrepancies, trial protocols, the accuracy and quality of data from which conclusions were drawn.
Scientists from universities in the United States, the Netherlands, Italy, France and Russia had critiqued the testing process and urged for greater transparency.
The scientists had raised concerns over the change in the primary outcome, vaccine efficiency which was recorded in September as well as further concerns about the enrolment of participants in the vaccine whose numbers varied between days 10-20 in the data submitted.
In their reply, the Sputnik V scientists said changes to trial protocol were made in November and revised documentation submitted to The Lancet following the rules. They said the primary outcome - i.e., vaccine efficacy - was "based on the number of cases of COVID-19 in participants who received both doses". This is "consistent with the primary outcome of other studies".
The testing parameters and diagnostic criteria were easily available in the original document's appendix and that other errors were the result of typing mistakes that had been corrected.
".. To date, safety and immunogenicity of Sputnik V has been confirmed in multiple studies... (including) in Argentina, where vaccination with Sputnik V began," they wrote.
"It is on this basis Sputnik V has received registration in 51 countries," the scientists said, adding that preliminary data showed an "appropriate safety profile" and pain at the injection site, fever and muscle pain as the most common adverse events.
Sputnik V had earlier run into issues with regulations in Brazil after Brazil's health regulatory body Anvisa claimed that the vaccine could pose a significant health risk. It has also been shipped to India as of May 1 although it must undergo quality testing before rollout.