The public health rationale for a two-week shift to online-only courses

In this Q&A, Dr. Steven Lacey, chief of the Division of Public Health at the University of Utah School of Medicine and leader of the Campus Incident Management Team, addresses decisions that led the university in July to expand its shift to online-only courses Sept. 27-Oct. 11, 2020. Questions are drawn from those pre-submitted for the Sept. 21 webinar on this topic.

@theU: What is the rationale for the upcoming two-week break?

Dr. Lacey: The rationale is rooted in two concepts: the chain of infection and the virus generation time. The chain of infection refers to the disease transmission cycle, where there is a host—in this case, a human—infected with coronavirus. The virus leaves that infected person, usually through droplets or aerosols during close contact, and the virus makes its way to infect a new person. The goal is to find ways to break that chain of infection, and one way to break the chain is to simply prevent people from gathering and spreading the virus.

Dr. Steven Lacey

The second concept I mentioned is the virus generation time. Generation time is the time duration from the onset of infectiousness in a primary case to the onset of infectiousness in the next case. For COVID, the generation time is approximately seven days. So, a two-week break is two full cycles of generation time, of potential transmission. And we can use this to break the chain of infection.

Knowing all of this, we worked with Drs. Linsey Keegan and Russell Vinik to model a whole suite of scheduling scenarios, from delayed starts to ending the semester early to breaks in the middle of the semester. We needed to disrupt the semester but minimize disruption to the teaching schedule. The final decision was made to start the semester on time, leverage the planned break with the upcoming VP debate and extend it to two weeks to break the transmission cycle and to go online after Thanksgiving.

I think this approach will serve us well.

@theU: What is the justification for setting the “circuit breaker” (and before that, fall break) for precisely the time when important national events are happening on campus?

Dr. Lacey: To be clear, we very purposefully took advantage of the timing of the upcoming vice presidential debate, which on its own necessitated operational changes on our campus.

Cases have and will accumulate within our campus community. So, any break in the semester will reduce cases. By planning for a break mid-semester, we have the opportunity to disrupt transmission and reduce case counts. We knew we had the one-week break planned around the vice presidential debate, but because of the seven-day generation time we discussed, a two-week break further slows down the virus. We considered extending the break either before or after the debate and used disease transmission models to optimize the schedule.

Now, other universities across the country are reaching our same decision, but they are reaching it under crisis conditions—having to suddenly go online to create this same type of break in transmission. But they weren’t planning to have to do this. We purposefully took advantage of the planned break around the VP debate, because it minimized disruption to the classroom.

@theU: The argument against fall break and for online instruction exclusively post-Thanksgiving originally was that we didn’t want students to disperse and then return to campus. The “circuit breaker” idea seems very much contradictory to that argument. Why should we expect that students won’t simply go to Moab, Sun Valley, Las Vegas, San Diego, or wherever, enjoy parties with others from around the US, and attend (or miss) their online classes from afar? In what way, in other words, is a circuit breaker actually supposed to work? 

Dr. Lacey: What my hope is, as a public health professional trying to look out for the university, is that students stick to their daily routines and log into their classes just like they always would. I hope they stick around the city and go about their daily lives employing all of the tactics that we have been doing over the past six months, which is being at home when that makes sense and physically distancing from folks and wearing a mask when we go out outside of our homes and taking classes online just as planned. And then we’ll resume after that two weeks.

As Dr. Reed said during our webinar, it’s about creating an interval where we minimize the frequency of interactions on campus, which detailed public health modeling suggests will be effective in disrupting the virus cycle.

All students living on campus will be tested if they traveled during this period. We have begun our asymptomatic randomized testing program, focusing first on students living on campus, and will expand that to staff and faculty on October 12, as we resume on-campus operations.

@theU: Why would you institute a policy of not coming to campus for two weeks as a “circuit breaker” or “fire break” in the middle of the semester, during which many students will go home, but then institute the opposite policy in November after Thanksgiving, don’t-come-back, and say it is because we “broke the bubble.” 

Dr. Lacey: We’ve already discussed the rationale for leveraging the required break around the VP debate by extending it an additional week to disrupt transmission in October. By going completely online at Thanksgiving, we reduce the number of “mixing events” that would occur with our students going back and forth between their family homes throughout the holidays. We encourage students to continue to practice physical distancing and masking when they return to their families.