When I first called Rebecca Lee Smith, a professor of epidemiology at the University of Illinois, she couldn’t pick up, because she was about to take care of a quick errand: getting a COVID test. She called back, and I expressed a bit of amazement that it only took about five minutes for her to get tested. “Less. Easily less,” she corrected me. “Two to three minutes, depending on how long it takes you to build up that amount of saliva.”
This, mind you, came just days after CBS News showed a line of cars snaked around for as far as the eye could see at a drive-through testing site in suburban DuPage County, the suburban county where I grew up in Chicago’s western suburbs. Someone I know in the Chicago area reported that he had to wait two and a half hours just to take his COVID test. His results would come back in 24-48 hours.
But a two-hour drive to the south, it was a different story. Smith knew she would get her results later that day. The university labs return test results in 5 to 8 hours.
The University of Illinois has garnered national attention – not all of it flattering – for its ambitious attempts to manage COVID-19 while offering in-person instruction. It is a massive effort that affects almost all aspects of the university’s operations. But the key to it all is frequent testing.
The university developed a saliva-based test that works by detecting pieces of genetic material in the novel coronavirus that causes COVID-19. It is essentially the same process for detecting the virus that the nasal swab tests use. But the saliva tests skip one step – the RNA isolation phase – that adds cost, time and even the potential for error in the more widely used tests
“The expense is $5 to $10 per test,” says Smith, one of the leaders of the campus’ response to the pandemic. “The logistics of collecting the samples might cost as much as the cost of the test itself.”
Keeping costs manageable is crucial in an environment in which 35,000 to 38,000 people are being tested twice weekly to keep the campus open.
Other types of tests, called antigen tests, are faster and cheaper too. But they are less reliable
, and they don’t detect infections as early as the molecular methods that the saliva-based tests use.
Yale University developed a saliva test, called SalivaDirect, and got FDA approval for its use before Illinois did.
Anne Wyllie, a research scientist in epidemiology at Yale who was one of the project heads in that effort, says researchers need to develop many different kinds of COVID tests, both to increase the supply of tests available to the public but also to make sure that there aren’t any bottlenecks in production of any one kind of test.
(Early in the pandemic, you might recall, access to COVID tests was slowed in some places because health providers couldn’t get the right kind of nasal swabs for the tests.)
Wyllie understands the need for tests that are as quick as antigen tests.
“It’d be great if we could get some sort of rapid tests that we do at home in the morning before we leave the house, before we go see a vulnerable member of the community,” she says. “That would be fantastic. And I hope we get there. But at the same time, we are not at that level yet.”
The antigen tests don’t detect infections until someone is already contagious, at which point, it’s too late, Wyllie explains. “If you want the outbreaks from happening, if you can get people as positive two to four days before they become symptomatic, you are able to isolate them before they are infectious and stop an outbreak.”
She noted that the SalivaDirect tests helped the NBA create a bubble for its players to allow its players to finish up their basketball season. But in an environment like that, COVID-19 could have spread rapidly if infections weren’t detected early.
Another other key to using the saliva tests is to use them frequently, which is a key component of the University of Illinois’ strategy.
“When we were deciding early on how frequently to test, we looked at the dynamics of the virus,” Smith says, “which is that your infectivity, as far as we know, peaks on Day 4 to Day 6 post-infection. If you test people once a week on average, you’ll find them a day to a day-and-a-half after the peak of infectiousness. At that point, they’ve done approximately 80 percent of the infecting that they will do. But if you test twice a week, on average, you’ll find people half a day before that infectiousness peaks.”
Up until now, most people on campus were required to get tested twice a week. People in high-risk locations had to get tested every other day. But, because of the national spike in cases, anyone coming back to campus after Thanksgiving will have to get tested once every two days.
“If you test people every other day,” Smith explains, “you’re getting them a day and a half before that infectiousness peaks on average. So that’s why it’s so important to have this frequent testing, because the majority of infection happens when you are asymptomatic or pre-symptomatic in the early phase of your infection. That infectiousness spikes really quickly: It goes from undetectable to peak in one to two days.”
With all the testing going on, university officials can detect outbreaks quickly. They have found that people’s social networks tend to closely align with the people the live near or with. So the university can require neighbors to step up their testing if there has been an exposure to prevent clusters from growing.
They noticed a small spike in COVID-19 cases after Halloween (which also coincided with the beginning of the Big Ten football season and the election), but, through testing and isolation, those numbers among undergraduates started heading down quickly.
It’s a different story for graduate students, faculty and staff. The university has more control over undergraduates, because undergraduates tend to hang out with each other, and all of them are subject to the university’s testing rules. But graduate students, faculty and staff are more exposed to people off campus, and their infection rates has continued to grow.
Smith stresses, though, that the rigorous testing regime is not enough to keep cases down. “The test doesn’t work unless you have the culture and the ecosystem around it, to make sure that people are isolated or quarantined safely and … to make sure that people are wearing masks and keeping their social networks small,” she says. “All of that is necessary. Otherwise the tests will just get overwhelmed by all of the transmission that’s happening in the population.”
To get tested, students and staff members can go to one of 20 sites on campus. People on golf carts pick up samples from each testing site every hour, and bring it to an on-campus laboratory that processes the tests.
If someone tests positive for the virus, they get a text within 15 minutes notifying them. The “Shield Team” also notifies the person about on-campus isolation procedures and directs them to resources they might need. They also tell the person that they will be getting a phone call from the public health department to conduct contact tracing, and that they have to answer that call.
To make sure everyone is keeping up on their testing, the university developed a smartphone app that not only delivers test results, but also has a status page. Students, faculty or staff have to show their status page before they’re allowed to enter university buildings. The feature is so popular that some neighborhood bars, in order to protect their own staff, require people to show their status page before they can enter there, too.
Still, there have been some setbacks. Early in the school year, the university discovered that some of its assumptions about how people would react to positive tests were, well, flat-out wrong. They had assumed infected students would isolate themselves and follow safety protocols.
“People who were supposed to be in isolation were hosting parties,” Smith said. “Not just going to parties, but hosting parties.”
The discovery forced campus officials to institute a two-week lockdown. It also prompted a story
in The New York Times
and some ribbing
from the internet comic XKCD (which, given Illinois’ reputation as an engineering and computer science powerhouse, had to hit a little close to home).