Like a lot of scientific discoveries

Serendipity

UPDATE: (a reader informs me that many don’t know that Alexander Fleming's discovery of penicillin was sparked by his accidentally leaving open a laboratory window that allowed the penicillin spores inside the lab, where they infected a Petrie dish, and so, he says, this reference is too obscure. Not for FWIW readers, surely! But just in case, this explanation).

Oxford Coronavirus vaccine hit 90% effective rate because of dosing error.

The Oxford University and AstraZeneca vaccine trials reached 90% efficacy by accident thanks to the “serendipity” of an error that led to some participants receiving half doses, it has emerged.

On Monday scientists revealed that the Oxford vaccine had an overall efficacy of 70%, but could be around 90% effective when administered as a half dose followed by a full dose a month later.

“The reason we had the half dose is serendipity,” said Mene Pangalos, executive vice-president of biopharmaceuticals research and development at AstraZeneca.

When university researchers were distributing the vaccine at the end of April, around the start of Oxford and AstraZeneca’s partnership, they noticed expected side effects such as fatigue, headaches or arm aches were milder than expected.

“So we went back and checked … and we found out that they had underpredicted the dose of the vaccine by half,” said Pangalos.

Instead of restarting the trial, he said researchers decided to continue with the half dose and administer the full dose booster shot at the scheduled time.

About 3,000 people were given the half dose and then a full dose four weeks later, with data showing 90% were protected. In the larger group, who were given two full doses also four weeks apart, efficacy was 62%

…..

Prof Sarah Gilbert from Oxford University, who led the research, said: “It could be that by giving a small amount of the vaccine to start with and following up with a big amount, that’s a better way of kicking the immune system into action and giving us the strongest immune response and the most effective immune response.”.