By Divya Rajagopal
AstraZeneca NSE 0.19 % will conduct a fresh trial of its Covid-19 vaccine to test a lower dose that was accidentally administered and showed better efficacy than the full dose in its studies. AstraZeneca CEO Pascal Soriot said on Thursday that the company expects this trial to wrap up soon and is hoping that it does not delay apprAstraZeneca/Oxford said this week it would assess why its vaccine candidate generated better efficacy at a lower dose. The statement came as the British-Swedish drug maker AstraZeneca started rolling submission of data to regulators across the world, while also battling perception about the varied efficacy data from the trial of the vaccine developed jointly with the University of Oxford.
The vaccine seemed to have worked better during trials in a group of about 2,700 volunteers who had received half the dose in the first round, followed by a full dose after a month, compared with those who received two full doses. The company reported a 90% vaccine efficacy in the first group and 63% in the second.
“We are delighted to study more on this,” Sara Gilbert, professor of vaccinology at the University of Oxford said during a press briefing on November 23 to share the interim results of the vaccine trial. She explained that this result might be because the vaccine was able to better mimic the actual infection.
“What we are able to do with vaccines is fool the immune system into thinking that there is a dangerous infection that it needs to respond to, but we do it in a safe way so that it generates cell response. And it could be possible that giving a small amount of vaccine and following it up with a full dose we get this result,” Gilbert said on Monday, while adding that more work would be needed to study that. Gilbert also has experience in developing a vaccine for the middle East Respiratory Syndrome (MERS), an infection caused by one form of the coronavirus.
Two divergent vaccine efficacy data raised eyebrows among medical experts and statisticians who asked for more explanations from the company on the results.
“AstraZeneca/Oxford get a poor grade for transparency and rigor when it comes to the vaccine trial results they have reported. This is not like Pfizer NSE -0.26 % or Moderna where we had the protocols in advance and a pre-specified primary analysis was reported,” Natalie Dean, an assistant professor at Biostatistics University .( ET )
