A single person can lead to 59,000 additional coronavirus infections over time, according to a recent study. That's where contact tracers come in.
Contact tracers play a big role in reopening the country and preventing future outbreaks, but it's not easy.
They're trained to interview people to find out if they're sick, where they've been and who they've been around.
Those who may be exposed will be tested, treated and quarantined if necessary.
But for it to be effective, more than a quarter million contact tracers are needed to cover the country.
Tech giants Apple and Google are stepping in to help states develop apps that use Bluetooth technology to alert people when their phone has been close to person who's sick with the coronavirus.
Virginia has 470 contact tracers and plans to hire 1,300 more by this summer.
Maryland teamed up with a research firm and hopes to reach its goal of tracing 1,000 cases and 10,000 contacts per day by the end of this week.
D.C. said it has received thousands of applications from city residents to fill 900 new contact tracing jobs.
Those who test positive for the virus should expect to hear from a contact tracer within 24 hours of the diagnosis.
Beware of contact tracing scams. Legitimate health department investigators will ask specifics about where they've been but will not ask anyone to reveal a Social Security number, bank information or photographs to confirm identity and will never ask for money.
Contact tracing helped eliminate smallpox in the U.S. in the 1950s and more recently was used in the Ebola outbreak.