23 November 2020

• AstraZeneca issues a press release with data from 11,363 participants in phase II/ III trials of its experimental coronavirus vaccine, citing overall efficacy at 70 percent, which increased to 90 percent, depending on the dosing schedule. A full dose of vaccine followed by a second full dose a month later was 62% effective (among 8,895 study participants), while giving a half dose initially, followed by a full dose was 90 percent effective (among 2,741 study participants). Researchers have speculated about possible reasons why the half-dose regimen was more effective, such as differences in age or past exposure to similar viruses, or that the initial full dose could have made people immune to the delivery vehicle (a chimpanzee adenovirus), dampening immunity afterwards – and the small sample size could have also contributed. Overall, there were 131 cases of COVID-19 among study participants; none of the people who received the vaccine needed to be hospitalized. There were no serious adverse events.

Oxford and AstraZeneca plan to apply for emergency authorization in Brazil, Britain and the EU. Regulatory approval may lag in the US, where trials were paused. The company has made agreements to sell the vaccine in high-income countries upon approval and it plans to supply 44 percent of all doses to low- and middle-income countries, where it will be priced at $3 to $4 per dose globally until July 2021, and indefinitely in low-income countries. The company says it could produce up to three billion doses of the vaccine – which can be stored in a regular refrigerator- in 2021. Sources 1,2, 3

• The US FDA has called a meeting of its Vaccines and Related Biological Advisory Products Advisory Committee for December 10th, to review Pfizer’s EUA application for its coronavirus vaccine, and asked members to reserve December 17th and 18th for meetings, possibly to review Moderna’s application for an EUA for its coronavirus vaccine. Source

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