Less than two months after Apple and Google launched a system to help government health authorities slow the spread of COVID-19 by tracing people exposed to the disease, the tech giants have attracted a modest amount of participation.

Multiple U.S. states and 11 countries, including Italy and Germany, are currently working with the companies to develop mobile phone apps to facilitate contact tracing, Dr. David Feinberg, vice president at Google Health, said on Wednesday at Fortune’s Brainstorm Health virtual conference.

“We think it’s a tool that’s important in the big concept of how you really do contact tracing,” he said.

Health authorities face a dire need to warn people who have been exposed to disease carriers, but tracing the contacts of infected individuals is a complex and difficult task. In May, Apple and Google launched an addition to their respective mobile phone operating systems that would help track incidental exposures to COVID-19. The system is designed to protect the privacy of individual users while also avoiding false reports. Health authorities could use the help; the novel coronavirus outbreak has so far infected 12 million people worldwide, including 3 million in the U.S. More than 500,000 people—including over 130,000 in the U.S.—have died.

Though some health authorities have criticized the privacy protection features of the Google and Apple system, which does not keep a record of the actual location of each encounter, Feinberg said it was designed to meet the authorities’ needs.

“We were really hearing from the public health world that they needed help with contact tracing,” he said. The goal is to be “able to set the phones so that folks that would have the information about who’s positive could use the technology to let people know that they’ve been exposed.”

“Google and Apple don’t keep any of the actual medical information. That’s at the public health level,” he added.