Undergrads account for a little over half of BU cases, testing turnaround time back on track thanks to new swabs
Now that Boston University is publishing its COVID-19 testing data on a public-facing dashboard, Gloria Waters, BU vice president and associate provost for research, and Judy Platt, director of BU Student Health Services, will provide a weekly update on the overall health of the BU community. They’ll explain how the testing systems are working, where the glitches are, and how well students, faculty, and staff are following protocols. This is their second weekly report.
Judy Platt watched Boston University’s coronavirus testing numbers this week to see if Labor Day weekend gatherings caused a spike in cases. So, she was pleased that the number of positive test results remained relatively low from September 9 to 15, with 12 students and 6 faculty and staff testing positive for coronavirus. Most cases, she says, continue to be asymptomatic.
“Looking at the week in review, there are no clusters or concerning areas of campus this week,” Platt says. One thing people should know, however, is that a fair number of positive test results are occurring in graduate students, faculty, and staff. “I think everyone assumes the majority of cases are coming from the undergraduate population, but based on our recent testing data, just over 50 percent of the total positive cases are in undergrads.”
Gloria Waters says the BU Clinical Testing Lab is now using new swab kits that were introduced two weeks ago, while phasing out kits that were used in August. The new kits improved testing turnaround times, helping the BU Clinical Testing Lab stick closely to its target of returning next-day results.
It’s possible, however, that the switch to new swab kits won’t be the last switch of the semester. Swab suppliers are cranking out batches of swab kits as fast as they can, and shipping them out in waves.
“The supply chain issues are a serious consideration right now,” Waters says. “In one case already, a shipment of swabs that we were scheduled to receive was diverted by the federal government, so we received the swabs much later than we were promised. We’ve secured multiple sources of swabs so that we don’t run out.”
There are still a few hiccups, with robots in the testing lab sometimes struggling to read barcodes, forcing a person to white out part of the barcode so the robot can read it. “We’ve also heard about a few of the swab kits being spilled at sampling sites, as you now need to break part of the swab and people are learning how to do that,” Waters says.
The supply chain issues are really complicated right now….We’ve secured multiple sources of swabs so that we don’t run out.
Waters and Platt also addressed a number of questions raised by the BU community about how active cases are determined to be recovered, how asymptomatic cases are differentiated from positive test results stemming from prior infection, why the number of invalid tests is no longer being reported, and why BU’s dashboard shows the total number of tests administered rather than the total number of people tested.
The term “recovered” indicates a person has come out of isolation—and to leave isolation, a person needs to meet a series of criteria established by the Centers for Disease Control and Prevention (CDC). “It must be at least 10 days since the onset of symptoms or the date of a positive test result; if that person had symptoms, they must be feeling improved for at least 24 hours, and they must have a normal temperature without the help of fever-reducing medicines,” Platt says.
The CDC advises that patients who have previously tested positive for coronavirus and recovered should not be tested for another 90 days, during which time they are noninfectious, but their body can continue to shed detectable amounts of the genetic material of the coronavirus. Platt says there have been rare instances at BU when someone who should not have been tested, based on those guidelines, did submit a sample to the BU Clinical Testing Lab. BU’s healthcare providers complete a clinical history interview with each member of the community who tests positive to determine if the result indicates an active case or is reflecting a previous infection.
“In some fairly unique situations, based on clinical interviews, we’ve been able to determine that someone had already been infected and tested before arriving at BU,” Platt says. Those individuals are then counted in the recovered category on BU’s dashboard. (They were previously accounted for in a dedicated category called “Confirmed Noncontagious,” but there were so few cases that the category was removed to streamline the dashboard.)
Other dashboard changes have also been made. The daily and cumulative numbers of invalid tests were removed from the dashboard, Waters says, because an invalid result requires that person come back for repeat testing within 24 hours. Once a test is determined to be invalid, it’s discarded from the testing totals, counting as neither positive or negative nor contributing to the daily and weekly testing totals. Only valid positive and negative results are tallied up for overall testing totals, which are used to calculate BU’s positivity rate.
Waters says additional changes are on the way. Now that the University-wide coronavirus surveillance plan has been in place for more than six weeks, and students, faculty, and staff have settled into on-campus or remote learning, BU plans to share the number of people in its testing population. Although the daily total number of tests represents the number of people tested that day, the cumulative number of tests that BU has administered, now over 100,000, represents many individuals being retested as part of BU’s surveillance program. Undergraduates are tested twice per week, and graduate students, faculty, and staff typically are tested once per week.
“We have been establishing the actual number of what our testing population is, and we’re going to put that number in the dashboard,” Waters says. “I do think it’s important that we can share that number.”
One dashboard reader also asked why the number of recovered cases appeared to be so high so early in the semester, compared to active infections. That’s because the total number of cases has been tallying up since late July when BU first began pilot testing. And undergraduates first began arriving on campus and entering the testing program as early as August 15.
“We’ve had positive cases nearly every day since we started robust testing of the community over a month ago,” Platt says. “Isolation is 10 days, not two weeks.”
Platt adds that there have been some students who had, through their daily attestations, reported symptoms before they had a test come back positive, so those students entered isolation from the first day of symptoms and not the day of the test result. “That could result in this number looking larger on the recovered side, even if the positive test results came after their illness had started,” she says.
Gloria Waters spearheaded teams of BU scientists in their development and deployment of a campus-wide COVID-19 testing program and chairs the Community Health Oversight Group, which scrutinizes BU’s testing data each day. Judy Platt, a member of BU’s Medical Advisory Group, oversees clinical management and isolation of students who test positive for coronavirus and helps manage BU’s contact tracing efforts.