Pharmaceutical giant AstraZeneca and the University of Oxford released positive results about their covid-19 vaccine being the frontrunner, claiming that it was on average 70 per cent effective, and could reach 90 per cent efficacy depending on dosing. But Researchers have raised several questions over the findings.
During the AstraZeneca and the University of Oxford’s clinical trials, some participants were mistakenly given half a dose rather than a full dose in their first round of shots, according to BBC News. Still, the trial continued and the researchers discovered those given the weaker dosage produced a better immune response. The results of the UK trial were published in The Lancet, but the full, combined results have only been revealed in a press release which didn’t include detailed numbers. The University of Oxford said that full results would be submitted to a journal. On Thursday, AstraZeneca announced plans for a new, global trial. According to Mark Toshner, a clinical trials doctor at the University of Cambridge, there have been reports, now confirmed by AstraZeneca, that the people in the half-dose subgroup were younger on average than the participants as a whole, which suggests that the 90 per cent figure may prove too high. Vaccines generally work better in younger people, says Hunter. Neither AstraZeneca nor Oxford released full details of the age profiles of the volunteers in both trials except to say that all were 18 or over. Another wrinkle is that the volunteers were all healthy or had “stable underlying medical conditions”. That may mean that the results don’t reflect how the vaccine will perform among vulnerable groups such as people with serious health problems.
Astrazeneca’s vaccine also got noticed for wrong reason when a volunteer in the Oxford University ‘Covishield’ COVID-19 vaccine trial flagged a serious medical condition called ‘acute neurological encephalopathy’ ten days after he was given the first dose on 1 October. The volunteer reported having had ‘memory loss, ability to reason and concentrate and personality change’, all of which are considered serious neurological and psychological symptoms. He went on to sue SII (which is conducting the trial along with the ICMR) for a compensation of Rs 5 crore. In response, SII filed a Rs 100 crore lawsuit against him for defamation.
On 9th November, Pfizer and BioNTech said in the press release that they had identified 94 cases of COVID-19 among 43,538 trial participants. The companies did not indicate how many of those cases were in the placebo group or among those who got the vaccine. But they said that the split of cases between the groups suggested that the vaccine was more than 90% effective at preventing disease, when measured at least one week after trial participants had received a second vaccine dose 3 weeks after the first. Eric Topol, a cardiologist and director of the Scripps Research Translational Institute in La Jolla, California said What’s missing, are details about the nature of the infections the vaccine can protect against — whether they are mostly mild cases of COVID-19 or also include significant numbers of moderate and severe cases and whether the vaccine can prevent people who show no or only very mild symptoms of COVID-19. Another missing detail is how well the vaccine works in different groups of trial participants. One key unanswered question is how long the vaccine’s effectiveness will last.
Recently questions have been raised on Bharat Biotech’s COVAXIN too when Haryana health minister, Anil Vij, who was given a trial dose of corona vaccine, Covaxin, has been tested positive for the Covid-19. On November 20, he was administered a dose of Covaxin at a hospital in Ambala, as part of its third phase trial, according to his twitter post.
Read More in December issue.