COVID-19 Forecast for El Paso County — Aug. 24

Plus, our resident microbiologist on why quarantine tends to last for 14 days

Good morning, and happy Monday. On this pre-pandemic date in 2018, comic fans were enjoying the first day of the Colorado Springs Comic Con at the Chapel Hills Mall Event Center. (Organizers postponed this year’s event to 2021 because of the pandemic.) 

Today, Phoebe Lostroh returns to give her weekly COVID-19 forecast for El Paso County. She also explains how she received her COVID-19 test results, and talks about the possible reasoning behind the 14-day quarantine for Loomis Hall. Lostroh is a professor of molecular biology at Colorado College on scholarly leave who is serving as the program director in Genetic Mechanisms, Molecular and Cellular Biosciences at the National Science Foundation.

🗣But before we get into today’s forecasts, we have some news about the next phase of this newsletter. A few weeks ago, we explained how our Faculty-Student Collaborative Grant, a summer research grant through the college that allowed us to report and publish this newsletter as our full-time jobs for 10 weeks, was coming to an end. 

An excerpt from that newsletter:

“Student publications at Colorado College don’t typically run over the summer, so we created this newsletter to fill the gap until those publications kicked back up again in August. They’re about to do that, so we’re now working on the next steps to integrate this project into those efforts.”

We can finally announce what those next steps are. Starting this week, the faculty members of this newsletter will be stepping away, and this newsletter will partner with The Catalyst, Colorado College’s student newspaper, to bring you the latest news a few times a week. Colorado College student Isabel Hicks ’22 is joining Miriam Brown ’21 and Arielle Gordon ’21, the authors of the newsletter this summer, to write, edit, and report about Colorado College and higher-ed during the pandemic.

➡️ICYMI: On Friday, we explained the COVID-19 guidelines at the Colorado College fitness center. We also rounded-up announcements from colleges and universities changing course and planning for remote fall semesters. 

👂LISTEN NOW: Miriam Brown ’21 and Arielle Gordon ’21, two of the students behind this newsletter, spoke to Colorado Public Radio’s Ryan Warner about the Loomis quarantine during Friday’s “Colorado Matters” show. Listen to their segment here. 

🔌READ THIS: On Friday, The New York Times referenced the article Brown, Gordon, and Hicks wrote about the #LoomisLockdown for The Colorado Sun. 

Phoebe’s Forecasts

NOTES: These forecasts represent her own opinion and not necessarily those of the National Science Foundation or Colorado College. She used the public El Paso County dashboard for all data. Lostroh prepared these forecasts Aug. 21.  

⚖️ How her predictions last week shaped up: Aug. 22 is the last day of Morbidity and Mortality Weekly Report week 34 in the national public health calendar. It is the 24th week since the first case was detected in El Paso County. Since March 13, 151 El Paso County residents have died of COVID-19. Last week, Lostroh forecasted that the rate of new cases might continue to fall, so she expected between 5,659 and 5,845 total cases reported as of Aug. 20. In actuality, there were 5,728 cases as of Aug. 20.

Predicted cumulative reported cases in El Paso County

🗝️ Key points: With college students returning to campuses, the pandemic is less predictable than usual because human behaviors are changing. Lostroh thinks El Paso County will probably see a total number of cases somewhere between the best-case scenario and the linear curve-fit again this coming week, because the percent positivity for nose-swab testing is also declining. That would mean between 5,872 and 6,076 cumulative cases by Aug. 27. 

It’s important to get a flu shot this fall, Lostroh says. States with strong public health systems such as Massachusetts are requiring K-12 and higher-ed students to get flu vaccinations this year because simultaneous influenza and COVID-19 outbreaks could tax the healthcare infrastructure. Scientists don’t know whether someone can be co-infected by influenza and COVID-19, whether infection with one makes someone more susceptible to the other, or whether sequential or simultaneous infections are more deadly than either infection alone.

Forecast for COVID-19 cases in El Paso County

🗝️ Key points: The exponential worst-case scenario is based on an exponential curve-fit to the two weeks prior to the statewide mask mandate. The exponential and linear scenarios are based on fitting an exponential curve or a straight line to the most recent 14 data points. (Both curves have an equally good fit to the data.) To make the best-case scenario, Lostroh averaged the total reduction in newly-reported cases over the past two weeks and subtracted that number from the new caseload every day, using the average number of cases in the last three days as the highest number of new cases.

14-day incidence annotated with the state’s viral spread thresholds  

🗝️ Key points: After 41 continuous days in the “very high viral spread” zone, El Paso County has crossed back into the lower “high viral spread” zone.  

14-day rolling average of daily new cases per 100,000 people in El Paso County

🗝️ Key points: The Harvard University Global Health Institute suggested the thresholds Lostroh uses in this forecast. El Paso County was in the orange zone from July 21 to Aug. 7 but has been in the safer yellow zone for about two weeks.  

Total nose-swab tests reported and percent positivity  

🗝️ Key points: The total tests reported in 14 days are plotted in pink using the left-hand axis, while the percent positivity in those 14 days is plotted on the right-hand axis in blue. During the period of time when percent positivity increased 2.9-fold, the total number of tests increased 2.5-fold. This means the reported positive cases really did rise — the increased percent positivity through July 28 cannot be explained by an increase in tests administered. In the last week, El Paso County’s percent positivity has fallen beneath the 5% threshold. This change is occurring while the total number of tests is holding steady, so it reflects a true decrease in COVID-19 cases in our community. Ideally, El Paso County will always maintain a percent positivity of less than 5% to enable the contact tracing and rapid testing turnaround necessary to contain the pandemic.

Q-and-A with Lostroh: Our resident microbiologist on the Loomis quarantine

This interview has been edited for length and clarity.

CC COVID-19 Reporting Project: You were recently tested for COVID-19. Tell us about your experience receiving your test results. 

Lostroh: My test results came through my normal healthcare system, so … that was easy, but it did take three days. And since I was concerned that I had been exposed, I didn’t want to get a test right away because I know you don’t become positive right away, you have to wait a few days. So by the time I found out [I was negative], I had been self-isolating for I think six nights, which is just not easy. Not easy for anybody in the family. So, it’s too bad that it took more than three days. It was a lot. It was like 76 hours. So not terrible, but that’s really not good. And I’m a crazy microbiologist so for a regular person to get this test and then wait, and then wait, and then wait ... not good. Not good. It wasn’t easy to maintain separation, and I just live with one other adult. So I can’t imagine how you would do that with kids in the house, for example.

CCRP: The students in Loomis have to quarantine for two weeks because of known exposure to the coronavirus. Why couldn’t the college instead just test everyone? Why is that 14-day window important?

Lostroh: It’s variable. That’s the problem. There are reports of the symptoms developing within 24 hours, and there are reports of symptoms developing two weeks later — actually three weeks is as long as it’s been detected. There was a known exposure, and 21 days later somebody finally tested positive or became symptomatic. It’s not a perfect bell curve, right, so 95% of people or something like that know that they have it by the time 14 days has been extended, but there are still some people that can get it later. So, the reason the 14-day window exists is that’s the most safe and most reasonable amount of time for people to isolate until they might either convert to having a high load of viruses detectable in their upper respiratory tract, or to having symptoms, so that’s where that comes from. It’s from early studies of people like on cruise ships. I think a lot of the work is also out of China. It’s shocking to me that it can take so long — or that both it can take so long and it’s so variable — and I think that could have to do with the dose. So it’s often the case for infectious diseases that if you’re exposed to a low dose, it takes longer for the infection to get really going in your own body, which means either for it to be detectable or for it to cause symptoms. So that’s why they can’t just test everybody now. 

CCRP: Where are we in terms of being able to use rapid saliva tests? 

Lostroh: The Yale team that invented them has an emergency use authorization, and so they’re trying to teach their technique to everybody. And I don’t know if anyone in Colorado Springs is setting up the facilities to do it, but it seems like a very good idea, and that it’s going to be very helpful, but … it’s like steering the Titanic because everybody’s been going on the nose swab and getting ready to do that. And then it’s like, oh now just switch what you’re doing, do this other thing. It seems like that should be an easy choice, but it’s probably hard to get some people to change. 

About the CC COVID-19 Reporting Project

The CC COVID-19 Reporting Project is created by Colorado College student journalists Miriam Brown, Arielle Gordon, and Isabel Hicks, in partnership with The Catalyst, Colorado College’s student newspaper. Work by Phoebe Lostroh, Associate Professor of Molecular Biology at CC and National Science Foundation Program Director in Genetic Mechanisms, Molecular and Cellular Biosciences, will appear from time to time, as will infographics by Colorado College students Rana Abdu, Aleesa Chua, Sara Dixon, Jia Mei, and Lindsey Smith.

The project seeks to provide frequent updates about CC and other higher education institutions during the pandemic by providing original reporting, analysis, interviews with campus leaders, and context about what state and national headlines mean for the CC community. 

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