Colleges & Covid-19: Time to Start Pool Testing


I. “Colleges Face Rising Revolt by Professors,” proclaims an article in today’s New York Times, in relation to returning to in-person teaching:

Thousands of instructors at American colleges and universities have told administrators in recent days that they are unwilling to resume in-person classes because of the pandemic. More than three-quarters of colleges and universities have decided students can return to campus this fall. But they face a growing faculty revolt.

…This comes as major outbreaks have hit college towns this summer, spread by partying students and practicing athletes.

In an indication of how fluid the situation is, the University of Southern California said late Wednesday that “an alarming spike in coronavirus cases” had prompted it to reverse an earlier decision to encourage attending classes in person.

…. Faculty members at institutions including Penn State, the University of Illinois, Notre Dame and the State University of New York have signed petitions complaining that they are not being consulted and are being pushed back into classrooms too fast.

… “I shudder at the prospect of teaching in a room filled with asymptomatic superspreaders,” wrote Paul M. Kellermann, 62, an English professor at Penn State, in an essay for Esquire magazine, proclaiming that “1,000 of my colleagues agree.” Those colleagues have demanded that the university give them a choice of doing their jobs online or in person.

II. There is currently a circulating petition of Virginia faculty making similar requests, and if you’re a Virginia faculty member and wish to sign, you still have one day (7/4/20).

A preference to teach remotely isn’t only to mitigate the risk of infection by asymptotic students, it may also reflect the need to take care of children who might not be in school full-time this fall. Yet a return to in-person teaching has been made the default option in many universities such as Virginia Tech (which has decided 1/3 of classes will be in person).

Other universities have been more open to letting professors decide for themselves what to do. “Due to these extraordinary circumstances, the university is temporarily suspending the normal requirement that teaching be done in person,” the University of Chicago said in a message to instructors on June 26.

Yale said on Wednesday that it would bring only a portion of its students back to campus for each semester: freshmen, juniors and seniors in the fall, and sophomores, juniors and seniors in the spring. “Nearly all” college courses will be taught remotely, the university said, so that all students can enroll in them. New York Times

It would be one thing if all students were regularly tested for covid-19, but in the long-awaited plan released yesterday by Virginia Tech, students are at most being “asked” to obtain a negative result within 5 days of returning to campus–with the exception of students living in a campus residence, who will be offered tests when they arrive. Getting tested is also being “strongly advised”.

If they test positive, they are asked to self-isolate (with the number of days not indicated). A student would need to begin the process of seeking a test several weeks prior to the start of class to ensure at least a 14-day isolation (even though asymptomatics are known to be infectious for longer). But my main concern is that even vigilant students would face obstacles to qualifying for testing, given the current criteria. A student who does not currently have symptoms would not meet the criteria for testing in Virginia, or in the vast majority of other states, unless they had been in close contact with infected persons. (There are exceptions, such as NYC.) This could be rectified if Virginia Tech could get the Virginia Department of Health to include “returning to campus” under their provision to test those “entering congregate settings”–currently limited to long-term care facilities, prisons, and the like.

It is now known that a large percentage of people with Covid-19 are asymptomatic. “Among more than 3,000 prison inmates in four states who tested positive for the coronavirus, the figure was astronomical: 96 percent asymptomatic.”(Link).

An extensive review in the Annals of Internal Medicine, suggests that asymptomatic infections may account for 45 percent of all COVID-19 cases:

“The likelihood that approximately 40% to 45% of those infected with SARS-CoV-2 will remain asymptomatic suggests that the virus might have greater potential than previously estimated to spread silently and deeply through human populations. Asymptomatic persons can transmit SARS-CoV-2 to others for an extended period, perhaps longer than 14 days.

The focus of testing programs for SARS-CoV-2 should be substantially broadened to include persons who do not have symptoms of COVID-19.”  

III.  An easy solution would seem to be to turn to “pooled testing”. It’s an old statistical idea, but it’s only now gaining traction [1] In the July 1 NYT:

The method, called pooled testing, signals a paradigm shift. Instead of carefully rationing tests to only those with symptoms, pooled testing would enable frequent surveillance of asymptomatic people. Mass identification of coronavirus infections could hasten the reopening of schools, offices and factories.

“We’re in intensive discussions about how we’re going to do it,” Dr. Anthony S. Fauci, the country’s leading infectious disease expert, said in an interview. “We hope to get this off the ground as soon as possible.”

…Here’s how the technique works: A university, for example, takes samples from every one of its thousands of students by nasal swab, or perhaps saliva. Setting aside part of each individual’s sample, the lab combines the rest into a batch holding five to 10 samples each. The pooled sample is tested for coronavirus infection. Barring an unexpected outbreak, just 1 percent or 2 percent of the students are likely to be infected, so the overwhelming majority of pools are likely to test negative.

But if a pool yields a positive result, the lab would retest the reserved parts of each individual sample that went into the pool, pinpointing the infected student. The strategy could be employed for as little as $3 per person per day, according an estimate from economists at the University of California, Berkeley.

The FDA has set out guidelines for adopting pooled testing, which employs the same PCR technology as individual diagnostic tests (link).

Universities should consider what they will do once a certain number of positive covid cases emerge. The Virginia Tech plan proposes to house infected students in a single dorm, but what about the majority of students who live off campus?  At what point would they switch to remote teaching? As much as everyone wants to return to normalcy, a class of masked students, 6 feet apart, doesn’t obviously create a better learning environment than zoom. By regularly conducting pooled tests, the university would become aware of increased spread as soon as a higher proportion of the pools return positive results– before we see an increase in serious cases and hospitalizations.

Chris Bilder, a statisticians at University of Nebraska–Lincoln has been advising the Nebraska Public Health Laboratory on its use of group testing since April. He and his colleagues have developed a newly released app to determine precisely how best to conduct the pooling for a chosen reduction in testing, and given estimate of prevalence. (Link)

I will add to this over the next few days, as new reports become available. Please share your thoughts and related articles, in the comments.

[1]I first heard it discussed weeks ago by someone on Andrew Gelman’s blog, but I don’t know if it was the same idea.

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8 thoughts on “Colleges & Covid-19: Time to Start Pool Testing

  1. Apology to subscribers: If you blog on wordpress, you know how that big, orange, pulsating “publish” button, right below the pale, “save changes” button, from time to time, results in accidentally posting something before its time. There were a few glaring typos in the first draft that inadvertently went up. Next, I decided that first picture looked more like a cashier than a college teacher, so I swapped it out. I was keen to get this up before the petition deadline tomorrow.

  2. One example of a university allowing faculty to choose between in-person and on-line teaching is Boston U. Even so, “The university plans to test every student, professor and staff member on campus by using the school’s labs and newly purchased specialized robots.
    …a volume of tests that will exceed 40,000.”

    I’m not sure if they’re doing pooled testing but it sounds like they are.

    Those universities who are so keen to have students come to a classroom in the midst of rising covid-19 numbers, might consider this variation: The students sit in class, and the screen is set-up for the faculty member to present the material via zoom or other on-line source. This would allow students to hear the lecture (very difficult if the presenter is wearing a mask) and also receive interactive answers to questions. The lecture is readily recorded, unlike in ordinary in-person classes, so that students can watch it and/or rewatch it later. There is absolutely no advantage to the instructor/professor being in the flesh, and the students gain whatever interaction and group discussion that is thought to make the in-class experience so valuable.

    I led a 6-week graduate seminar via zoom recently–my first time. Among the many pluses is the fact that we were able to fully focus on the subject matter, rather than on our precarious situation living through a pandemic.

  3. I have heard from several Virginia Tech faculty that they have been given the option of teaching online or in person, so it appears from that small sample that Virginia tech faculty have been able to give input.

    The practice of pooled testing sounds like a very good idea, if the base infection rate is low.

    • Hi Bill:
      I don’t have all the information and I don’t have an official statement on this (I only know from colleagues who are teaching this year), but my understanding is that the default is teaching in person, and one has to mount an appeal to opt out. So, it might depend on what’s meant by “option”. The fact is that VT is planning on teaching 1/3 of its classes in person, so clearly not everyone can opt out. (Maybe this is only a goal.) Still, if you’re hearing something different, the policy may vary by department. As far giving “input” on the decision-making, there were the usual committees, undoubtedly with some faculty ‘representation’. VT has had a significant on-line presence even before the pandemic, so it would seem appropriate for them to do so during it. Still, I’m sure they have to weigh the economic situation of the University.

  4. Thomas Adajian, a professor at James Madison U, and one of the originators of the petition, tells me there is no longer any deadline for signing.

  5. I agree with this Time article. Opening Virginia Tech will be like placing a cruise ship with a growing % of covid cases smack into the middle of Blacksburg turning it into a hot spot overnight.

    “These institutions need to be honest about the trade-offs. They should publish their estimates of the number of infections, hospitalizations, and deaths that re-opening will cause. That will allow students, instructors, parents, and the wider community to better understand how much suffering must be endured, and by whom, as the price for the benefits of reopening. These institutions should also state clearly what level of illness will trigger another shutdown.”

  6. FDA authorizes pool testing with up to 4 people in a pool. That’s not so much of a saving, but it’s something. I’m not sure it will cut down the required number of test kits sufficiently for our universities to pursue it. Their preference appears to be to wait and see how bad the coronavirus incidence rate becomes, and then…I don’t know what.

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