After two weeks of zero active COVID-19 cases on campus, members of the Vassar community were shocked to see the VassarTogether online dashboard report five new cases on Sept. 25. President Elizabeth Bradley shortly thereafter sent an email explaining that the five students who had tested positive for COVID-19 were isolated. Bradley wrote that contact tracers identified 10 close contacts of those who tested positive, but that the test results did not seem to be connected to a single event.
No one was more shocked by the test results than the students who tested positive. One such student (who asked to stay anonymous due to privacy concerns) said they were confused by the results because they had been cautious and were following all the rules, such as staying on campus and not attending unmasked gatherings. They explained that the contact tracers also expressed disbelief about the results—none of the students were experiencing symptoms, the students who tested positive were not in close contact with each other and they all testified to following safety precautions. Dean of the College Carlos Alamo-Pastrana elaborated, “We do not know how these students may have gotten exposed. Contact tracing and our investigation showed that they do not live in the same house, do not have classes in common and all attest that they have not left campus. It is because of this that we investigated these cases.”
Matters were further complicated when the students who tested positive were retested. The anonymous student confirmed that they were retested twice in the following days after receiving the positive test result. One of these retests went through a different laboratory than Bioreference Laboratories, the lab the college usually uses for COVID-19 testing. Both retests came back negative for this student, and for the four others that had received positive results the same day. To this student, this was confirmation that they did not have COVID-19. They recalled thinking, “Okay, can we go now?”
False positives are rare, but not impossible. Vassar uses the molecular polymerase chain reaction (PCR) test, which is widely considered to be the most reliable. While the data is not conclusively known, studies have shown the false positive rate of molecular PCR tests to be anywhere between .3 percent and 3 percent. Dean Alamo-Pastrana emphasized that when testing a large number of asymptomatic people, there will inevitably be a small number of false positives. He further explained, “Our protocol in handling all positive test results is to follow state health guidance. That guidance is that the students must remain isolated.”
Because molecular PCR tests only react to COVID-19 RNA, the most likely explanation for false positives is contamination of the testing sample. President Bradley explained in an email to the Vassar community on Sept. 30 that an investigation was launched by the local and state health departments in collaboration with Bioreference Laboratories and Westchester Medical Center Valhalla Lab after the suspicious positive tests. The results of this investigation showed that the positive results were not run in the same batch, were not handled by the same test administrator and were not collected at the same time. Bradley wrote, “The determination of the investigators was that these positive tests were valid and not compromised.” New York State guidelines required that these students isolate for the remainder of their quarantine period.
“The first five days of isolation in the Alumni House were very uncomfortable,” the anonymous student explained. Along with the stress of having to quarantine, the student felt unsure about when they would return to campus. However, they also emphasized the competence and empathy of Vassar’s administration throughout such a complicated situation.
The anonymous student remains doubtful they had COVID-19 because of their diligence with social distancing and their lack of symptoms. When asked further about the specifics of the investigation and retests, Dean Alamo-Pastrana commented, “In order to preserve confidentiality, we cannot discuss testing results beyond what was reported on our dashboard.” While students may take comfort in Vassar’s consistently low incidence rate, relying on relatively new testing methods inevitably leads to some degree of uncertainty. Positive cases on campus have since decreased to two active cases as students follow social distancing guidelines, giving hope to the Vassar community that campus will remain safe.