COVID-19 testing capacity was one of the biggest factors in deciding whether to reopen college and university campuses across the country this fall.
Of the types of diagnostic tests widely available, most schools who offer campus-wide testing opted to use the polymerase chain reaction (PCR) test, in which the student’s saliva is collected and then sent to an off-site lab. PCR tests work by adding enzymes and primers to a genetic sample (in this case, saliva) and letting the primers bind to the virus particles.
However, according to the Mayo Clinic website, PCR tests only work on DNA, and the genetic code for COVID-19 is found in RNA, the nucleic acid that carries a gene’s instructions and information. Advancements in science have created a workaround for this issue.
“Fortunately, viral enzymes to convert RNA into DNA were discovered decades ago, and have been harnessed, along with PCR, to find unique signatures in RNA, too,” the website said.
This is the method that Lewis & Clark administrators chose to employ for the campus-wide testing that took place between Aug. 24 and Sept. 4. According to Vice President of Student Life and Dean of Students Robin Holmes-Sullivan, LC will soon be changing its main method of virus detection.
“We just recently got (the rapid test) machines, but we’re still waiting for them to deliver the test kits,” Holmes-Sullivan said, “But (those are) antigen tests, and so it’s not quite as sensitive as the molecular test is, which is why we used the molecular tests for testing all the undergraduates.”
While PCR tests look for genetic material from the virus, antigen tests look for active viral molecules on the virus’s surface. Antigen tests can be conducted at the point of care, are far less expensive than the PCR test and return results in approximately 15 minutes.
According to Holmes-Sullivan, after the antigen test kits arrive, the school will transition to using those as the main diagnostic test. However, since antigen tests have high rates of false negatives, the PCR saliva tests will remain on hand.
“If you get a negative [antigen test result], we have to follow that up with a saliva test,” Holmes-Sullivan said.
This is not the only method LC is using to detect the coronavirus. In addition to diagnostic testing of students, the school has partnered with the company Clean Water Services at the suggestion of James M. “Jim” Spencer ’85, an LC trustee who also sits on Clean Water Services’s board of directors. Clean Water Services will provide effluent testing to all residential buildings on campus.
Effluent testing, also known as sewage or wastewater testing, is done by running an RNA test for the virus that causes COVID-19 in the wastewater, including water from toilets, showers and sinks of a residential building.
According to the Centers for Disease Control and Prevention (CDC) website, effluent testing is effective because the SARS-CoV-2 virus strain can be detected in feces in cases with or without symptoms. Sewage testing is also a leading indicator of COVID-19 presence in a community.
“(Researchers can use effluent testing) to find evidence of the virus at the neighborhood scale, which could provide an early warning sign of the virus in a community,” the Clean Water Services website says.
Clean Water Services is providing weekly testing of LC buildings, and the samples are being sent to the lab at Oregon State University (OSU). Ely O’Connor, senior public information specialist at Clean Water Services, said LC is taking samples from eight locations on campus.
“We collect and extract the samples and send them to OSU where they are analyzed for virus concentration,” O’Connor said over email. “We then take that data and put it into a dashboard we built for (LC) and help with data interpretation and response.”
When considering how best to respond to the possibility of COVID-19 cases on campus, the college had to consider cost when deciding how to implement testing procedures.
“(The Executive Council) decided that (effluent testing) could be a form of surveillance testing that was affordable for us and could be an effective … way of surveilling students without them having to have an invasive test, without the big cost of the test going to the students or to the school,” Holmes-Sullivan said.
Although LC is taking presumptive positive effluent results seriously, as with the cases in Copeland Hall, West Hall and the Forest Halls, Holmes-Sullivan made it clear that this testing is not “the whole toolbox.” The school is still mostly relying on diagnostic molecular tests for now and will transition to a more antigen-heavy approach as soon as the antigen test kits arrive.
With regard to the actual testing process on campus, Facilities Services, Health Promotion and Wellness and the Office of Public Relations did not respond to a request for comment by the time of publishing.