One of the largest COVID-19 vaccine trials currently underway will have over 500 volunteers actively testing its solution by the middle of next month. Researchers at the University of Oxford have already secured that number of participants, including a representative sample of people between the ages of 18 to 55, for a large-scale randomized clinical early and mid-stage trial of its potential vaccine, which uses a harmless, modified virus to trigger an immune response that is also effective against the novel coronavirus.

The trial will divide a total of 510 participant sent five groups, with one group receiving a follow-up, booster shot of the vaccine after the original does. The technology behind the vaccine has already been used in developing about 10 different other treatments, but will require an approach that includes setting up different test groups in different countries to ensure representative results, since infection rates are varying greatly place to place with prevention measures in place, study lead Sarah Gilbert told Bloomberg.

The team behind the vaccine is also still seeking additional funding to help scale manufacturing, since it aims to begin producing it in volume following the six month period this human trial phase will span. The goal is to have mass production up and running by this fall, under the assumption that the trial proves the potential vaccine effective, with a final stage trial of 5,000 people and the potential to begin providing some doses for use by frontline healthcare workers by as early as September.

The Oxford trial is one of just a handful that have progressed to the human testing phase, but more are coming online all the time. Existing clinical human trials from Moderna and Inovio are underway in the U.S., and those have also expressed the potential for earlier access for emergency use prior to broad rollout following the initial clinical results.

Even if there is some availability by fall of some of these vaccine candidates (and that assumes they even prove effective), that doesn’t mean they’ll be broadly available: That will still require further testing, and scaling manufacturing, as well as working out distribution and administration – all processes that will add months of work. Already, however, the unprecedented nature of the COVID-19 pandemic has resulted in new efficiencies in the development process, and more could follow in these extraordinary times.