(Update 9-20-20: due to a data correction, the percentage of cases interviewed on the day assigned was corrected in the blog below)

The case investigators at Public Health—Seattle & King County are able to reach the vast majority of people who test positive for COVID-19 in King County. And most people are taking the important step of isolating themselves during their contagious period.

A new data dashboard shows the numbers, and it demonstrates the rapid growth of Public Health’s contact tracing efforts. Highlights include:

• Since the spring, the team has grown to 61 members who investigate over 500 cases each week (roughly 95 percent of all cases in King County).
• Each week, the team interviews roughly 85% of those positive cases and reaches over 90% of their named contacts.
• Each month, the team provides hundreds of referrals to testing, grocery delivery, financial assistance, and medical services to cases and contacts.
• Approximately 80% of those who test positive are staying home before the investigators contact them, which can help limit the spread of COVID-19.

What is Contact tracing?

Contact tracing is a public health intervention designed to identify people who may have been exposed to an infectious disease and prevent the spread of infection.  Contact tracers interview people who have tested positive and help them recall close contacts they might have exposed to the virus. Next, they call those contacts to arrange testing and ensure that they go into isolation or quarantine. 

Along with wearing a mask, social distancing, handwashing and testing, contact tracing is an important tool for protecting our community from the COVID-19 pandemic.

The program’s progress reflects broad cooperation from people with COVID-19, their families and the people they come into contact with.

What to expect if a contact tracer calls

Contact tracers will first confirm that they are speaking to the right person by confirming your name, address, and date of birth. They will not ask about your Social Security number, finances or immigration status — and they will not reveal your name to others.

They will then ask about your symptoms, where you have been, and who you have been with.  It is important that you answer those questions to the best of your ability.  Your answers will help the contact tracers identify other people who may be infected and limit the spread of COVID-19. 

The contact tracers will also tell you where to get tested and get the support you need to stay in isolation and protect your family, friends, co-workers, and fellow community members.

Contact tracing in King County

During the first months of the epidemic, the health department did not have the resources to provide contact tracing to everyone with COVID-19. It received substantial support from the state Department of Health. Since then, the county has built up its staffing and is now conducting nearly all contact tracing in the county.

If you receive a call from a contact tracer,  your phone will identify the caller as Public Health, WA Health, 206-263-8480, or 206-263-0267.

If they contact you, please answer the call.

Other highlights on the dashboard

Contact tracing provides the health department with critical data on the strengths and limitations of community efforts to control COVID-19. Here is more of the data we have collected so far:

• Contact tracers interview two-thirds 58% of cases on the same day that they learn about them.
• Most people with COVID-19 have been infectious for 7 days before their contact tracing interview.
• Eighty percent of people with COVID-19 are in isolation at the time of their contact tracing interview, but only half went into isolation before getting a test. 

These data demonstrate why it is critical for people to isolate and get tested right away if they develop symptoms of COVID-19.

Public Health will update the dashboard weekly. A Washington Department of Health report on the state’s contact tracing program as of Sept. 16, 2020, is also available.

Doing your part to help control COVID-19 

Contact tracing is one important piece of a larger strategy to stop the virus.  Here are some other things you can do to help stop COVID-19:

• Wear a mask when you are around other people.
• Practice social distancing. (Try to keep at least six feet of distance from others.)
• Wash your hands frequently.
• If you develop symptoms, get tested and go into isolation right away.

Originally published on Sept. 16, 2020