NEW DELHI: The Covid-19 vaccine by AstraZeneca and Oxford University has come into the eye of a major controversy after it has emerged that there was a goof-up in the human trials of the potential vaccine that resulted in participants being given two different dosing regimens.
It has also come out that the trial participants, based on which the early results have been released, consisted of very few elederly individuals among whom the efficacy of the potential vaccine was found to be lower than other groups, but this information was not made public.
On Monday, Swedish-British pharmaceutical major AstraZeneca had said in a press statement that their vaccine candidate was 70% effective on average in a late-stage study.
As per the details of the interim analysis of the phase 2 and 3trials from the UK and Brazil, one dosing regimen given to 2,741 volunteers showed efficacy of 90 % when the vaccine was given as a half dose, followed by a full dose at least one month apart, the firm had said.
Another dosing regimen, given to 8,895 individuals showed 62 % efficacy when given as two full doses at least one month apart.
The difference in the doses given to the trial participants had left scientists in many parts of the world perplexed but no explanation was offered for that.
It has now emerged that the dose showing the higher level of effectiveness was tested in a younger population and also that the half-dose was given to some people because of an error in the quantity of vaccine put into some vials.
None of this, however, was disclosed in the press release by the company on Monday and has now led to concerns that lack of transparency could lead to erosion of trust in the vaccine, among the front-runners coronavirus vaccines globally.
The development has implications for India too, as the vaccine, to be produced by Serum Institute of India, is pegged to be the earliest Covid-19 vaccine to be available in India.
Experts pointed out that the lack of transparency in releasing crucial information and data could lead to stricter scrutiny by regulators in many countries and mistrust among people.
“This episode has many elements which are problematic,” said bioethicist Anant Bhan.
“Apart from cherry-picking data to show that its vaccine is highly effective, the company also didn’t reveal that the sample size of elderly participants was very small,” he said adding that it may be only serendipity that seems to have led to a dose which showed higher efficacy.
“All this is very concerning and looks like there was pressure within the company to release efficacy data quickly after results by Pfizer-BioNTech and Moderna,”Bhan said.
Vaccine scientist Gagandeep Kang, in a tweet underlined that SII can ask for emergency use authorisation of the vaccine based on 62% efficacy in India the per protocol interim analysis from UK & Brazil, with their chemistry manufacturing controls data for process and safety and immunogenicity Indian trial data.
“But they cannot claim 90% protection,” she wrote.
SII meanwhile in a statement claimed on Thursday that the AstraZeneca-Oxford vaccine is safe and effective and even the lowest efficacy results are at 60-70%, making it a viable vaccine against the virus.
“That said, varied age groups with different dosage forms will result in slight variations and efficacy. We must be patient and not panic,” it clarified. “The Indian trials are running smoothly with strict adherence to all the necessary processes and protocols. So far, there are no concerns. However, we are going through the data that is available and will make further statement, if needed."