[ad_1]
The University of Oxford and AstraZeneca vaccine trials were 90% effective by accident thanks to the “serendipity” of an error that led some participants to receive half doses, it has emerged.
On Monday, scientists revealed that the Oxford vaccine was 70% effective overall, but could be around 90% effective when given as a half dose followed by a full dose a month later.
“The reason we take half the dose is chance,” said Mene Pangalos, executive vice president of biopharmaceutical research and development at AstraZeneca.
When university researchers distributed the vaccine in late April, around the beginning of the partnership between Oxford and AstraZeneca, they noted that the expected side effects, such as fatigue, headaches or arm aches, were milder than expected.
“So we went back and checked … and found that they had underestimated the dose of the vaccine in half,” said Pangalos.
Rather than restart the trial, he said the researchers decided to continue with half the dose and give the full dose booster injection at the scheduled time.
About 3,000 people received half the dose and then a full dose four weeks later, and the data shows that 90% were protected. In the largest group, which received two full doses also four weeks apart, the efficacy was 62%.
The scientists said they still couldn’t explain why half the dose provided better protection, but said it could be that it activates the immune system differently.
Oxford University Professor Sarah Gilbert, who led the research, said: “It could be that by giving a small amount of the vaccine to start and follow up with a large amount, that is a better way to get the immune system into action. and giving us the strongest immune response and the most effective immune response. “
Professor Andrew Pollard, director of the Oxford Vaccine Group and lead investigator on the trial, added: “What we don’t know at this point is whether that difference is in the quality or quantity of the immune response. And that is something we are going to be looking into over the next few weeks. “
The vaccine has yet to be approved by the Medicines and Health Products Regulatory Agency, but it could be available in the coming weeks if it is given the go-ahead.
