As Butte County continues to reopen, the work of identifying cases of COVID-19 in the community continues. Along with that comes the task of identifying who those infected have come into contact with to try to further limit the spread of the disease.
NSPR’s Andre Byik spoke Wednesday with Monica Soderstrom, division director of Community Health for Butte County Public Health, about how the county is investigating cases, and what they’ve learned in the process.
Here are highlights from their conversation. You can also listen at the top of the page.
On contact tracing
Whenever a lab-confirmed positive case is reported to the health department, we begin with a case investigation where we receive medical records, we interview the patient, and when we're interviewing them, we determine their infectious period. And then we work with them to identify those that had close contact with them during that infectious period, which could include the time before their symptoms were apparent. And so — it's make a list of the people that they have been in close contact with, meaning those that were within six feet for longer than 10 minutes of time. And then we reach out to those people to inform them that they have been a close contact of someone who has tested positive. And we inform them about measures that they need to take while in quarantine, to help prevent the spread of the virus to others in their circle.
On the typical infectious period
Usually people become infectious two days before their symptom onset. And then it can range for 10 days, minimum, beyond the time their symptoms appeared. And so when we put someone in quarantine, we usually put them in quarantine for 14 days from their date of exposure because within that timeframe if they were going to develop coronavirus and have symptoms, it would likely show up between two and 14 days after they've been exposed.
On measures they advise close contacts to take
Well, number one, we would like them to stay home. People that are ill with the coronavirus are in isolation, and those who have been exposed as a contact are in quarantine. Or if there's someone who's at high risk, they can be in quarantine. But for those who have been exposed to someone, we'd like them to be at home for 14 days. We of course want them to be able to stay separate from most people if they can. They should be wearing a mask, even if they're around other people in their own home that maybe weren't a contact. I'm taking all the same measures that we take in the public as far as washing their hands and social distancing from others. We ask them not to go out in public unless they absolutely have to. And if so, like, maybe they were getting ill and they wanted to go see their doctor. We asked them to call their doctor ahead of time, and let them know that they've been a close contact and wear a mask when they're going to see their own health care provider.
We also ask them to monitor themselves for symptoms twice a day. We make sure that they have a thermometer to take their temperature and we go over the different symptoms that they might see related to the virus. And then we have them on a text monitoring system that we enroll them in, if they're able to text. And they let us know whether they’re symptomatic or not. If they don't have the ability to text, then we make an arrangement for them to call us or we call them.
On the average number of people someone with COVID-19 in Butte County would have potentially exposed
So far for the cases that we've had in Butte County, we've had an average of about 10 contacts per case. Sometimes those are contacts in the home, sometimes they're contacts in their circle of friends or at their work. But typically, it's been about 10 contacts per lab identified case.
On the movement of people who’ve contracted the virus
It's been really interesting for us. I think the thing that's fascinating about case investigation and contact tracing, it's really detective work. And it's really looking for patterns. We have an epidemiologist in our department who helps to look at patterns. And what we're really seeing right now, especially since we've had our stage two reopening in Butte County, is it really is pretty widely present in our community. Initially with our cases, we could pinpoint pretty readily where they had been exposed. Whether they had been a traveler, or whether they knew they had been exposed at work from another positive case — it was a pretty direct link. And now we're finding people that are not really sure where they had come in contact with someone. They don't remember being anyone around anyone who was ill. They don't know of anybody who had a positive case.
So again, now it's what we really kind of expected with the reopening. And the reason we needed to increase our ability to respond quickly with containment measures, which is really case identification through more testing. And then through contact tracing, was able to pinpoint as soon as we could, who is testing positive who their contacts are, and helping those contacts stay quarantined, so that we can stop the spread of the virus in the community.
On keeping a mental or physical log of your activity
That is actually really helpful. Early on we saw you know some people on social media saying hey, I've learned you can keep a daily diary of who you've seen and where you've been. And we have people that kind of do that normally anyway, especially in today's day with, you know, texting and Facebook and different social media, many people have been very helpful. They've known where they've been and who they've seen. And so any kind of memory joggers that people might want to use to help them when we talk to them, we encourage that. It's helpful to us and I think it helps them be sure that if they've come in contact with any close friends or coworkers or people in the community, we've had a lot of really positive response for those that we've called to try to help us put the puzzle together for their particular situation.
On how many case investigators the county has
We currently have six full-time nurses that are working as case investigators. And we now are going to be moving some of our nurses who have been working as contact tracers. We're moving them into disease case investigation. So we'll soon have eight people pretty much working full time, just on this case investigation.
On contact tracers vs. case investigators
We have a whole separate group of people. We have people that are doing case investigation, and then we have a team of people that are doing the contact tracing. And most of those people are people who have other jobs within public health, but they've been cross-trained in order to be contact tracers. Some of them are doing it full time, and some of them are doing it part time while they're still doing their other public health, usual role. Our contact tracers have been trained not only by one of local public health supervisors, but most of them now have taken an online virtual academy that's been offered by the state through the California Department of Public Health. So even if this wasn't their usual role in public health, they've received additional training in order to help them in this role.
On how many asymptomatic cases they’re seeing
I couldn't give you a number right now but we are seeing more asymptomatic people, or people who thought, 'Hmm, I thought I just had allergies.' Or you know, 'I don't really remember being sick,' but they are now testing positive. So again, that is why we say it is in our community, and people should not let their guard down. Wear your mask, wash your hands, use social distancing. And don't go out unnecessarily. Don't put yourself in situations where — if you're the only person wearing a mask in a crowd, it's probably not a good place to be. Stay out of large crowds. And just really protect yourself while you're protecting your fellow community member.
On the level of cooperation they’re seeing with investigations
Fortunately, we have a really close-knit community. I believe that unfortunately, after the Camp Fire, we had a lot of people who really came together, called Butte Strong. And I think that COVID is just another challenge that's facing our community. And thankfully, people want to help, they want to help their fellow Butte County resident. And we have had very good cooperation with those that we've identified as cases to help us really understand maybe who they've been in contact with or who maybe they had been in contact with themselves, to be exposed. And we've been very grateful that our small community has been able to really to this point contain this very well. Many larger communities don't have the small town camaraderie that we have. So I think it's been a benefit for us unable to keep our numbers as low as we have been.
On whether customers of a grocery store, for example, would be notified if a positive patient had visited
That is very atypical in a need for COVID because unlike measles, where the virus is spread in the air, and has an airborne transmission and hangs in the air for hours, COVID is a droplet transmission. And so that's again why you have to really be within six feet of someone for 10 minutes or longer to have a true risk of exposure. So the need to identify customers in a large setting is not the same as it would be like, for instance, with measles. That's why the individual close contact tracing is so important with COVID. Because it really is about distance and time.
On how we should continue to respond to the threat of COVID-19
I would just like the public to know that as much as Butte County is doing to respond really strongly still with our containment measures, with investigation, with testing through our lab and encouraging testing through other labs, through our contact tracing, really still the answer to this is to try to maintain those measures that we all practiced before the reopening. That is really what stops COVID in its tracks. And until we have a vaccine, that is the thing that we can all do to really keep COVID at bay and keep the numbers low in our community.
This interview has been edited for brevity and clarity. Click the “play” button at the top of the page to listen to the entire interview.
