Campus woes: Limits of testing, importance of quarantine
What is happening with COVID-19 cases on local college campuses?
Many colleges and universities around the country delayed the start of the second semester, seeking to avoid the expected surge in cases over the holidays. By now, though, those who are returning in person have done so. And it has proven challenging even on the far side of the national winter peak. Whereas in much of the country case levels remained moderate until right before Thanksgiving, most areas are now at infection levels similar to those from early November when most campuses closed. Numbers are dropping, but it is a much more fraught context in terms of potential exposure than September.
Students on many campuses in the fall were undergoing assurance or surveillance testing, meaning that they were screened for infection at regular intervals regardless of exposure or symptoms. That helped schools keep tabs on cases that would otherwise have gone undetected, given the tendency for minimal symptoms in that age group. When the students went home over winter break, though, that testing stopped. Student exposure changed but was not eliminated, so cases would have continued.
Most schools did require students to get tested before or upon return for this semester — and even more importantly they started or resumed assurance testing. While the entire country was experiencing the winter surge, there were likely also many cases (even if not a surge per se) in the college-age population, just undetected. That cohort has brought some of those under-the-radar cases back with them to campus. Luckily they are being identified, largely thanks to assurance testing.
Why didn’t having students provide negative tests to start with catch all the cases?
That comes down to the limitations of testing, which are frequently misunderstood and ignored. Many people imagine that if they’ve had a negative COVID test, they have a clean bill of health; some even mistake it for a license to behave less carefully.
It seems straightforward: A negative test says you don’t have COVID, right? Well, there are caveats. It really says you probably didn’t have COVID at the time of the test — though it might be wrong; false negatives are not uncommon — and it doesn’t say anything at all about how you have fared since. In fact, a test can’t identify an infection you harbored at the time if it was still incubating. You could test negative, possibly several times at short intervals, and later go on to develop a case based on an exposure that happened before the tests — not to mention subsequently!
Take this timeline for example: You’re a college student who lives with your family. Unbeknownst to anyone, someone in your household picks up an asymptomatic case and becomes infectious about a week before classes resume, say on Sunday, Jan. 24. So you get exposed that day. The virus enters your system, but is incubating. You dutifully go and get tested. At that point, you are still incubating and not yet detectable (also not yet infectious). By Sunday, Jan. 31, you are on campus with your negative test results — even multiple negatives — in hand, but also possibly either already infectious or about to become so some time in the next week. Perhaps you interpret your negative tests as indicating that you are “safe,” and you let down your guard upon seeing your friends again. Or maybe you are careful but you still unintentionally expose people you share living quarters with …
It’s easy to see how this can go wrong. The two- to 14-day incubation period can really trip us up when it comes to understanding test results — especially in combination with being infectious before and/or without symptoms.
But if that is the case, then what is the point of all the testing?
It is admittedly less useful on an individual basis, but on average it will help to identify more cases, especially pre-symptomatic and asymptomatic ones that would otherwise be easily missed. What’s more, combining testing with careful quarantine helps make the test results much more reliable. If, for the two weeks before returning to school, you isolated from your family members, wearing masks when together and taking meals apart, you could have more confidence that a negative test was indicative of a clean bill of health and that there wouldn’t be an infection lurking/incubating in your system. Once back on campus, of course, you would want to maintain your caution and vigilance with masks, distancing, hygiene, and avoiding indoor gathering, recognizing everyone else as potential infection incubators, too.
It’s complicated to juggle the logistics of quarantine and the logic of testing. It can seem unreasonable and too confusing, but as an alternative to locking down entire campuses after outbreaks, such precautions look more manageable in retrospect.
Every bit helps — so keep wearing those masks, too!
Samantha Pearson is the executive director of Lewisburg Neighborhoods, a non-profit in Union County, and is collaborating on regional public health messaging with the Lycoming-based Let’s End COVID group.