In the P3 program, the 60-day clock begins when a blood sample is taken from a person who has fully recovered from the disease of interest. Then the researchers screen that sample to find all the protective antibodies the person’s body has made to fight off the virus or bacteria. They use modeling and bioinformatics to choose the antibody that seems most effective at neutralizing the pathogen, and then determine the genetic sequence that codes for the creation of that particular antibody. That snippet of genetic code can then be manufactured quickly and at scale, and injected into people.

Jenkins says this approach is much faster than manufacturing the antibodies themselves. Once the genetic snippets are delivered by an injection, “your body becomes the bioreactor” that creates the antibodies, she says. The P3 program’s goal is to have protective levels of the antibodies circulating within 6 to 24 hours.

DARPA calls this a “firebreak” technology, because it can provide immediate immunity to medical personnel, first responders, and other vulnerable people. However, it wouldn’t create the permanent protection that vaccines provide.