In an effort to curb virus-caused infectious diseases that kill millions of people each year, Defense Advanced Research Projects Agency (DARPA) is embarking on a very ambitious project. It wants to develop vaccines that can shape-shift.

DARPA has announced its new program called INTERfering and Co-Evolving Prevention and Therapy (INTERCEPT), where the main goal is to create a vaccine for broad-spectrum viral strains that not only may adapt to the changes of the strains but also may outpace their development, allowing the vaccine to prevent the spread of the infection.

Viruses are some of the simplest types of infectious agents in the world, but they can also be very difficult to treat since they evolve or introduce new strains. Although there are vaccines available, many of the world's killers like human immunodeficiency virus (HIV) and Zika don't have any yet.

Meanwhile, some vaccines like those of flu, a very common viral condition responsible for 6,000 deaths in the United States, have to be changed every year, and sometimes they don't always work.

"We need a new paradigm to stay ahead of these moving targets," said DARPA manager Jim Gimlett.

To do this, DARPA is planning to use therapeutic interfering particles (TIPs), which can act like a regular virus, only that they're a dud - they don't have any effect even when they enter into the host cells.

However, these "tiny virus-like entities made of laboratory-grown snippets of genetic material packaged inside protein shells" will then try to outcompete and outpace the real virus for protein shells. As the real virus replicates itself, so will TIPs, but because the latter can be designed to do so faster, they can ultimately lower the viral load by 20 times, significantly reducing the spread of infection, and make symptoms more manageable.
Moreover, since TIPs are made of genetic materials like real viruses, they can also evolve and hopefully be prepared to tackle potentially new viral strains.

This project still has a very long way to go, though, including identifying the right types of harmless TIPs, which are capable of thriving in the body for long periods, and testing for their efficacy and safety. To begin, DARPA schedules a Proposers Day on April 29 in Arlington, Virginia.