Yesterday AstraZeneca opened a US branch of the worldwide Phase III study of its Covid-19 vaccine, developed by Oxford University. The study, funded by NIAID and BARDA, will enroll 30,000 subjects in 80 sites across the US.

AstraZeneca / Oxford candidate AZD1222:

The first volunteers in the study were dosed on Monday Sept. 1 at the University of Wisconsin School of Medicine and Public Health in Madison, WI. AstraZeneca expects to add 50 more subjects per week beginning next week.

Two-thirds of subjects will get two shots of the AZD1222 candidate vaccine, four weeks apart, and one-third will get a saline placebo. The study is double-blind so no one will know which subjects receive the live vaccine. In earlier trials in the UK and elsewhere, AstraZeneca had opted to use as control a vaccine against meningococcal bacteria. The advantage of doing so is that subjects are less likely to guess who got live vaccine and who the placebo, assuming the meningococcal shot produces some sort of reaction at the site of the injection. The other two drug-makers’ Phase III trials in the US employ a saline placebo.

AstraZeneca

This candidate vaccine uses as its vehicle a replication-deficient adenovirus that causes colds in chimpanzees. People don’t have immunity against this adenovirus and so it doesn’t present the headwinds faced by candidate vaccines developed in China and Russia using Ad5, which does infect hu­mans.

The study will recruit 30,000 subjects ages 18 and up — the study de­scrip­tion at clinicaltrials.gov says that “adults and older adults” are eligible. I don’t know whether “older adults” means 65+, 85+, or exactly what. The AZ press release does say “all adult age groups,” so that is encouraging.

Medical sites in 36 states will be participating, including (for a change) Minnesota and all of the adjacent states. The enrollment site does not yet list AstraZeneca’s study as actively recruiting. But I learned that Health Partners is enrolling 1,500 volunteers for this study in Minnesota. I won’t be applying, because one of the screening criteria is: “Have an increased risk of getting COVID-19, like working in a close-contact profession.”

The Phase II/III trial for the Oxford-developed vaccine candidate began earlier this summer recruiting up to 17,000 volunteers in England, South Africa, and Brazil. AstraZeneca plans to initiate studies in Japan and Russia later in the fall; the company has already received approval for the Russian branch, according to reports.

Last week the head of the FDA said the agency was open to considering emergency use authorizations for vaccine candidates before their Phase III trials end. Some press accounts mentioned AstraZeneca in this context, but the company declared that it was not involved in any talks with the US towards this end.