Published on Jun 04, 2020

  • Published on Jun 4, 2020
  • The goal of contact tracing is to break the chain of transmission.
  • If you test COVID-19 positive, you'll be asked who you've had close contact with  (less than 6 feet distance)  for 15 to 30 or more minutes in the last two weeks.
  • Contact tracing is a resource and labor-intensive job that relies on a patient's knowledge and technology such as calendar apps, social media, and public surveillance footage.
  • There's an unprecedented need for contract tracers at local health departments across the country, and some positions only require a high school diploma. 

Video Transcript


JOHN WHYTE: You're watching Coronavirus in Context. I'm Dr. John Whyte, Chief Medical Officer at WebMD. We hear a lot about contact tracing, but what exactly does that mean? To help provide some insights and unpack it, I've asked Dr. Crystal Watson. She's a Senior Scholar at Johns Hopkins Center for Health Security. Dr. Watson, thanks for joining me.

CRYSTAL WATSON: Thanks very much for having me.

JOHN WHYTE: Let's start off with explaining to viewers what exactly does contact tracing mean and what does it entail.

CRYSTAL WATSON: So it all starts with a positive case. If someone is notified that they have COVID-19, um, that person would be contacted by a public health official. So someone calling them, um, and trying to ask them how they're doing, connect them with medical care if that's needed, if they need to go to a hospital or be seen by someone.

But then also asking them who they may have been around during the time that they have been infectious with the virus. So that is during the time that they've had symptoms as well as about two days before they develop symptoms.

By doing that, we find out who the case has been around during that time, and then public health can reach out to those contacts and notify them that they may have been exposed to the virus, ask them to quarantine at home for 14 days, which is the incubation period, the-- the kind of high end of the incubation period of the virus. And by doing that, um, we break chains of transmission. Because if those contacts are indeed infected, then they're not out in the community spreading the infection to others. JOHN WHYTE: Let's be practical. And I'd like to understand if we know how effective contact tracing is. Because if you asked me who I talk to and what I was doing last Thursday and where I was, that could be somewhat challenging. And I might be around people that I didn't know. So say I went and picked up coffee at the mobile Starbucks. You know, how do you reach those people?

CRYSTAL WATSON: Right. So contact tracing is a tough job. It's really resource intensive, labor intensive. But a good contact tracer will know how to ask questions and, um, kind of elicit the information that they need. So we can use things like social media to remind people of where they might have been, um, to look at your calendar to see where you went on those days.

Um, but there are those instances where you've been out in a public place and may not know the people that you were around. Um, first of all, we have to define what a significant contact is. So it's not everyone you've come into contact with just in passing out in the community.

It really involves, uh, a close contact, so within six feet. We're all trying to maintain that six feet of social distancing. And, uh, for 15 minutes or more is kind of the standard definition that-- that we're using right now. The CDC says 30 minutes or more, so it's subjective.

But at-- at Johns Hopkins, we've-- my colleague, Emily, Dr. Emily Gurley, has developed this-- a free training on Coursera. Um, and the definition that they're using for that training for contact tracers is that 15 minutes of sustained contact with someone.

JOHN WHYTE: So it's not as if I simply pass you by.



CRYSTAL WATSON: Right. Um, but you may be in situations, if you're standing in line at Starbucks or at a grocery store, um, for a long time, you may meet those criteria. So what public health then does is they become kind of disease detectives. They, um, go to the grocery store, contact that-- that store and see if there's surveillance footage. Just try to identify people that may have been at risk from that situation.

JOHN WHYTE: And we know the public health departments have historically been underresourced.


JOHN WHYTE: And here we're talking about and have already started reopening. More and more people are going to get out. Contact tracing is going to be more important. We're talking about test and trace. Um, how many contact tracers do you think we need? Rockefeller Foundation and some others are saying we should have 300,000 contact tracers. Do you know how many we have now and how many we need to scale up to?

CRYSTAL WATSON: That's a good question. So our center has estimated that we need about 100,000 as a baseline. It may-- it may need-- we may need more than that if we have large epidemics of the disease, but that has been our estimate.

I think before this crisis started, estimates from the Association of State and Territorial Health Officials, or ASTHO, were that there were about 2,200 contact tracers around the country, um, at least at the state level. And so that's a-- a massive difference between 2,200 and 100 or 300,000.

So, um, states and localities have been working to begin to scale this up. Um, we're in different places and different parts of the country, but I think the-- the latest estimate from a survey that NPR did was that we now have about 60,000 contact tracers either in the works, um, in planning, or that are being trained and-- and deployed now. So that's a massive scale up already, but we're still not quite there yet.

JOHN WHYTE: What if a viewer wants to become a contact tracer? Do you need any special training? Are there going to be opportunities as we think about scaling up the number of people we need?

CRYSTAL WATSON: I think there are going to be opportunities to contribute to this. Um, it really depends on the jurisdiction that you are living in and I'd like to stress that contact tracers really should come from the community that they want to help because it helps with understanding the context of that community and-- and the population.

So, um, it's important to really get in touch with your state or local health department because they are going to be the ones that are coordinating, um, the hiring process. But I do think that there is an opportunity to get involved here. Um, contact tracing, as I said, is very labor intensive, but it doesn't require really specialized skills. You don't have to have a medical degree or a public health degree to do this.

Um, so really, I think a lot of people have the skills to do it. You really need to be empathetic. You need to be able to conduct a good interview, to record data with fidelity. Those are the types of skills that are needed. And so I do think people can get involved if-- if they'd like to.

Our course that-- that was just released by Johns Hopkins, I think maybe two weeks ago now, it gives a baseline. So anyone who's interested in contact tracing, whether they want to apply for a job or not, can take that basic training and that will get you primed to-- to know what contact trac-- tracing is and all that it involves.

JOHN WHYTE: Where would folks find out about this free online course?

CRYSTAL WATSON: Yeah. The online course is at, and you can go into that website and search for COVID-19 contact tracing and you'll be able to find it there.

JOHN WHYTE: I said it was free. Is it free?

CRYSTAL WATSON: It is free. It is free. Yep.

JOHN WHYTE: OK. What about privacy issues? Someone may not want their neighbor to know that they were exposed. So how does that come into play?

CRYSTAL WATSON: Yeah. So contact tracing isn't something that we're just doing for COVID-19. This is something-- this is a tool that public health has used for decades for other types of diseases. So they're actually-- public health officials are actually very practiced at keeping this sensitive information private.

So it's sensitive information regarding your health as well as your whereabouts. So, um, that information should not and will not be shared with other people. Um, you won't be identified to the contacts that you name. Um, it's-- it's really important that public health, uh, keeps this information private and they're very practiced at doing so.

JOHN WHYTE: I want to spend a minute or so talking about the role of tech. And Apple and Google have announced initiatives in terms of, um, identifying, you know, who may have had exposure to someone who has COVID-19. There's apps that have been discussed, but there's also been challenges in getting the public interested in such an app. And in order to do that, you really need to have at least more than half of the population participating. Um, what are your thoughts on the role of technology in-- in helping contact tracing?

CRYSTAL WATSON: I really look at-- at technology, these digital contact tracing technologies, which are fairly new, as potential work force multipliers. We still need that 100,000 person workforce, uh, to scale up in this country. Um, but if we have an app that's useful to public health, that can help identify more contacts, potentially those contacts that-- that the case does not know intimately, or identify contacts more quickly, I think that could be very useful.

This-- this disease spreads pretty quickly. And so the faster we can identify contacts and ask them to quarantine, the more successful contact tracing will be. Um, that said, there are definitely challenges with application of these technologies. I said that-- that they're new. We haven't really had a lot of experience with them being deployed.

And so we need to reassure the public that, um, these technologies will protect their privacy. Um, but also, we need to be assured that the data will be useful to public health. And so a lot of different technology companies are do-- working on different approaches for this and we're going to have to see how that plays out over the next few months, I think.

JOHN WHYTE: How important is contact tracing to prevent resurgence or a second wave?

CRYSTAL WATSON: I think it's critically important. Um, right now, um, we have been working to-- to kind of flatten the curve and slow spread of this virus through these population-level social distancing measures. And they've done a pretty good job. It's-- it's not perfect. It's kind of a blunt tool.

What contact tracing is is-- is a more precise tool. And so once we lift these population level measures, we need to have something in their place to be able to control the spread of the disease. And so what contact tracing really does is it allows us to manage the-- the pandemic on a case by case basis.

And, um, it really helps us, kind of more surgically, break chains of transmission and stop epidemics from happening. And so it-- even if there is a surge in cases and an epidemic that occurs, contact tracing will allow us to get our arms around it more quickly and there won't be this large number of, um, unidentified cases out in the community. So I think it's critically important in the coming months, because, um, until we have a safe and effective vaccine, which is really the gold standard here, we need something else to control the virus.

JOHN WHYTE: Dr. Watson, I want to thank you for sharing your insights today.

CRYSTAL WATSON: Very happy to share with, uh, with your audience. Thank you very much.

JOHN WHYTE: And I want to thank you for watching Coronavirus in Context.