The organizers of the virus-tracking program Seattle Coronavirus Assessment Network (SCAN) have currently paused the initiative in order to address concerns raised by the US Food and Drug Administration (FDA).

SCAN, which is supported and partially funded by Microsoft co-founder Bill Gates, was suspended soon after Gates wrote in a Tuesday post on his personal blog that it has the “potential to become an important tool for health officials seeking insights about the spread and behavior of the virus.”

The goal of SCAN is to track the spread of the novel coronavirus in the Seattle area by sending self-swab tests to local residents.

“One of the innovations of SCAN is an easy-to-use, at-home, self-swab test kit. The key advantage of this at-home testing approach is that people don’t need to go to a clinic, where they risk exposing themselves or others to infection,” Gates explained in his blog post.

“People interested in participating in SCAN can enroll online, and, once approved, they get a test delivered directly to their home. After individuals complete the nasal swab test, a courier service picks it up from their home and returns it to SCAN for processing. Anyone who has a positive result gets contacted by a public health worker who provides guidance on how to care for themselves and their families. And all participants can check their results online.”

During the last seven weeks, tests have been sent to around 12,500 people, including those with and without COVID-19 symptoms. SCAN organizers have said it is important to also test subjects who aren’t feeling sick to learn more about the virus and track positive cases that are asymptomatic or go undetected for other reasons.

The project got started due to an arrangement with the FDA that permits public health officials to issue Emergency Use Authorizations (EUA) for COVID-19 tests that are developed in their states. However, recent revisions in the FDA guidance mean that SCAN must receive separate federal authorization to return test results.

“SCAN has been operating under an EUA from the Washington State Department of Health. On March 16th, the FDA granted states authority to issue EUAs for tests developed and used by laboratories within their states. However, we have been notified that under revised guidance issued on May 8th, a separate federal EUA is now required to return results,” SCAN wrote in a May 13 news release.

However, SCAN also affirmed that it is “actively working” with the FDA “to address their questions.”

“We’re pleased to see that the agency’s recent guidance now includes provisions for home-based self-collection of diagnostic samples in specific circumstances. This paves the way for continued progress in expanding access to safe, reliable, convenient, and scalable testing options,” SCAN added in its release.