Oxford / AstraZeneca vaccine to be tested in new trial after questions over its data

However, the 90% claim was called into question after the vaccine’s overall efficacy was noted to be 62-70% in trials in Brazil and the UK, while the figure of 90% was was achieved alone among less than 3000 UK participants who received a lower dose following an error

. Researchers cannot explain why the accidental lower dose was more effective. AstraZeneca therefore plans to conduct another trial, testing only this lower dosing regimen. “Now that we’ve found what appears to be better efficacy, we need to validate that, so we need to do further study,” Soriot told Bloomberg. He said that because the efficiency is high, fewer patients would be needed.

Age issues: There are also concerns that the low-dose trial may not have included anyone over the age of 55, so this second trial should give researchers the opportunity to confirm the vaccine’s effectiveness in older populations. The U.S. Food and Drug Administration may also require more data from a wider range of ethnicities, ages, and genders before granting approval. Full peer-reviewed data from the original trial will be published in The Lancet in the coming days.