A group of global scientists has claimed that Russia's coronavirus vaccine, which is world's first, produced dubious outcomes in clinical trials.
Though earlier this month initial reports on whether the Sputnik V vaccine safely produces an immune response were published in the Lancet, international scientists have flagged up several apparent anomalies, reports Mail Online.
Graphs showing the level of immune response in different people, at different time points after taking the vaccine, appear to show repeating patterns of data.
The experts, who have written to the medical journal to raise the alarm, suggest it is 'unlikely' to be accidental.
They have requested the data behind the graphs, which the Russian vaccine team has said it will provide.
Dr Christoffer van Tulleken, an associate professor at University College London, said: 'This number of irregularities add up to a series of coincidences that appear extremely unlikely.
'It may be that there are simple explanations or an honest mistake, but anything that undermines public faith in vaccines costs lives.'
The Lancet routinely publishes letters criticising studies in the journal, and can invite researchers to respond, as the Russian team did in detail in this case.
Dr Denis Logunov, of the Moscow research institute, which developed the vaccine, said: 'We categorically deny the accusations of inaccurate statistical data published in The Lancet.'
Russia was the first country to approve a vaccine after only a few months of trials and President Vladimir Putin said it had been tested on one of his own daughters.