The goal here is to “develop strategies and effective countermeasures against rapidly evolving pathogens that pose a threat to public health,” the NIH explains. That is, so-called “gain of function” research in pathogens may help scientists anticipate how viruses may spread and evolve, and therefore how to stop them from leading to unmanageable pandemics. The NIH’s funding pause on such studies went into effect in October 2014 but has now been lifted.

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Still, the very idea likely sounds like a horror movie—which is why the NIH has listed out detailed criteria for what kind of lethal virus research would make the cut for government funding. “We have a responsibility to ensure that research with infectious agents is conducted responsibly, and that we consider the potential biosafety and biosecurity risks associated with such research,” said NIH director Dr. Francis Collins in a statement. “I am confident that the thoughtful review process laid out by the HHS P3CO Framework will help to facilitate the safe, secure, and responsible conduct of this type of research in a manner that maximizes the benefits to public health.”

For instance, the research would have to be both ethically and scientifically justified. You can’t just go around enhancing any old virus; it would have to be one that feasibly poses a threat to humans. And institutions involved in conducting such studies would have to prove they have the technology and protocols to carry it out safely.

Pandemics like the 2014 Ebola outbreak, or the wildfire spread of MERS, SARS, and flu are difficult to contain once they’ve already infiltrated human population centers—which is why global health experts have urged new research and incentive models to prevent pandemics from occurring in the first place. Making lethal viruses deadlier in a controlled setting could be one part of that effort, in the NIH’s eyes.