AstraZeneca: The vaccine dosing mistake could prove to be a godsend

A dosing error in corona vaccine development could prove to be a godsend for AstraZeneca. The scientists actually accidentally gave the study participants only half the dose of the vaccine candidate as expected. In retrospect, the lower dosage in the first of two vaccinations proved particularly effective in protecting against Covid-19, as the interim results of large-scale tests published on Monday showed. “The reason we took half the dosage is a happy coincidence,” said Mene Pangalos, head of non-cancer research and development at AstraZeneca, the Reuters news agency.

Shortly after AstraZeneca partnered with the University of Oxford in late April to develop a corona vaccine, the drug was tested on volunteers in the UK, Pangalos said. Side effects such as fatigue, headache or arm pain were milder than expected. “So we went back to the start and checked.” It turned out that the dosage was half the expected. But because they didn’t want to stop testing with these people, they continued with a second vaccination with the full dose.

This particular vaccination schedule – a first half-dose vaccination followed by a full dose after one month – showed 90 percent effectiveness in the relevant study with thousands of test subjects, AstraZeneca said Monday. According to the results, the variant with two full-dose vaccinations is only 62% effective. However, more data is needed, Andrew Pollard, head of the vaccine group at Oxford University, told the BBC. “I think this is a really exciting and surprising result that we need to look into further.”