Wednesday, April 8, 2020

Developing smarter COVID-19 testing to inform public health

Developing smarter COVID-19 testing to inform public health

As we’ve rolled out a community-based COVID-19 testing program in conjunction with the State of California, we’ve received many questions about how we collect data during the screening process, why it matters, and who is eligible for testing through our program. In short, the process is designed to quickly, securely and accurately screen and test individuals with concerns about COVID-19 while also giving state public health officials high-quality information to respond to this crisis. As former Commissioner of the FDA during the Zika virus crisis, I have a healthy respect for the value of taking action to deal with an infectious epidemic. I also developed a deep appreciation for the importance of reliable data to support the best decisions about policy and healthcare. 

The goal of our work with the California community-based testing program is to rapidly screen and test high-risk people who do not need immediate medical attention, such as those exposed to COVID-19 or frontline healthcare workers and first responders. It is also critical for health officials to have timely and accurate public health data to help determine where the novel coronavirus is likely to spread and where the most vulnerable communities are. While many public health departments have systems for tracking positive tests, more comprehensive information across counties and systems is currently lacking. Data from individual testing sites and aggregate data could inform decisions the local and state authorities will make about social distancing measures and provide a basis to adjust screening criteria to ensure that people with the greatest need for testing receive it.

Over the past few weeks, we and our partners have established four community-based COVID-19 drive-through testing sites in San Mateo, Santa Clara, Sacramento and Riverside Counties. We’ve quickly and responsibly scaled each site and intend to launch with three new sites in California this week. 

As COVID-19 spreads exponentially, we must move fast to stand up more community-based testing centers. On March 31, there were more than 186,000 confirmed cases in the U.S. up from roughly 30 on March 1, according to the Centers for Disease Control and Prevention (CDC).  As the pandemic continues to spread, hospitals will need to focus on people with significant illness and healthcare workers. During this acute phase, screening less symptomatic people away from a healthcare setting can help avoid spread of infection and consumption of stressed hospital resources.  

Additionally, a secure and connected system that enables a person to register, get an appointment, complete the test quickly and receive a secure test result can help communities efficiently establish a systematic testing approach. Our Community Based Testing Guide ( provides publicly available information about what we have learned that will be useful to others setting up testing sites.

Why We Need Data for Public Health

Because COVID-19 represents a public health emergency, federal, state and county public health agencies are required to track the results of the tests and analyze data about people who are infected to inform decisions about how to manage the epidemic. Typically, there is a significant lag between the return of a test result and the collection of more detailed information, and little is known about what is different about people whose tests are positive versus those whose tests are negative. The Baseline COVID-19 Program’s technology platform is designed to collect this information, which by law is handled confidentially by public health authorities. 

Anonymous screeners are readily available on the website and elsewhere, and some allow people to input information and find a potential testing site without identifying themselves. These screeners also have an important role in stemming the epidemic, but they do not enable receiving an appointment for the test, nor do they enable followup of a person linked to their test result. Accordingly, we support the use of available screeners, but the Baseline COVID-19 Program has a specific use in the testing and public health ecosystem.

Since our launch on March 15, more than 60,000* individuals have completed the public health screener through the online tool. The screener is dynamic and the criteria may change over time based on public health data and directives by the California Department of Public Health (CDPH) on populations of greatest concern. As we scale testing at these facilities and begin opening new ones, the triage algorithm will be adjusted in response to CDPH objectives. As a result, it’s possible that individuals who are not currently eligible for testing through this program may become eligible in the future, as public health guidance involving testing shifts. 

In-depth data on COVID-19 spread and its impact on specific at-risk populations such as the elderly or people with multiple illnesses can help health authorities make more informed decisions and tailor containment efforts at the local, county, and state level. Data can also help determine which underlying health conditions pose the greatest risk to people infected with COVID-19. In the U.S., preliminary data show that those with diabetes mellitus, chronic lung disease and cardiovascular disease appear to be at higher risk for severe COVID-19-associated disease, according to a March 31 report by the CDC. Further data will help validate those findings. 

Along with increasing visibility into positive results across counties, collecting public health data through smarter screening and testing can also help public health officials see how initial findings map to key risk factors.

We will continue to develop the Baseline COVID-19 Program and to share updates on our progress as the pandemic runs its course. We will provide individuals and public health authorities with information needed to improve decisions about individual health and to reduce the impact of the epidemic as much as possible. As the pandemic continues to evolve we will adapt our approach based on data and the guidance of public health officials who have served California well in order to help individuals who need to be tested for COVID-19 while also providing information for the critical role of evidence-driven policy that is so critical to successful management of health crises.

-Robert M. Califf, MD, MACC, Head of Clinical Policy and Strategy for Verily and Google Health

*Based on data collected as of 4/06/20.