At a Glance
As schools reopened and extracurricular activities resumed in the fall of 2021, it was anticipated that the coming respiratory season would be characterized by numerous respiratory infections, some caused by SARS-CoV-2 and others caused by more typical respiratory viruses including rhinovirus, respiratory syncytial virus, and influenza. Schools needed to develop a strategy to quickly distinguish between cases of COVID-19 caused by SARS-CoV-2 and cases of more typical respiratory viruses. The Department of Health Services in Wisconsin developed testing options for K-12 schools which included the use of BinaxNOW Antigen Self-Tests for individuals with symptoms followed by confirmation through PCR for those who were antigen negative.
The goal of this project was to identify ways to improve upon the statewide testing by comparing the results of repeated at-home antigen tests to at-school PCR tests and evaluating whether oral “lollipop” swabs were as effective as nasal swabs for identifying children with COVID-19. The results of this project suggest that the at-home BinaxNOW test was at least as sensitive as the nasal PCR test. Additionally, lollipop samples performed better than the nasal swabs and were preferred by 92 percent of students.
The Challenge
As schools reopened and extracurricular activities resumed in the fall of 2021, it was anticipated that the coming respiratory season would be characterized by numerous respiratory infections, some caused by SARS-CoV-2 and others caused by more typical respiratory viruses including rhinovirus, respiratory syncytial virus and influenza. As a result, schools needed to develop a strategy to quickly distinguish between cases of COVID-19 and cases of more typical respiratory viruses. Further, schools needed to implement policies to facilitate a prompt return to school for those students whose infection was not caused by SARS-CoV-2 and whose illness was improving.
The Department of Health Services in Wisconsin developed testing options for K-12 schools. One of the testing programs which was to be implemented in Madison included the use of BinaxNOW Antigen Self-Tests for individuals with symptoms followed by confirmation through PCR for those who were antigen negative. However, the resources required for confirmatory PCR testing were high in cost and limited in availability. Both the BinaxNOW and PCR tests required nasal swabs which may be objectionable to many elementary school children.
Project Goals
The goal of this project was to identify ways to improve upon the statewide testing program for SARS-CoV-2 through two specific hypotheses. First, researchers hypothesized that consecutive at-home BinaxNOW testing will be non-inferior to the single at-school PCR testing program. To test this hypothesis, over-the-counter BinaxNOW antigen tests were distributed to volunteer families and a protocol was created to ensure families could perform and report test results accurately to the school. The second hypothesis was that performing PCR on lollipop swabs, which children suck on for ten seconds, is non-inferior to performing PCR on nasal swabs. To test this hypothesis, researchers worked with Madison Metropolitan School District to incorporate a lollipop swab for PCR at the same time that a symptomatic student receives a nasal swab for PCR as part of the DHS program.
Results
This project encountered challenges related to changes in partnering laboratories, test kit shortages, and obtaining consent from children’s parents and guardians to join the study. Despite these challenges, 99 children were enrolled in the study at their school and had nasal PCR performed. Of these children, 91 were symptomatic and received a negative BinaxNOW antigen test while eight were positive for COVID-19 on the antigen test. Seventy-three of the 91 children who had a negative antigen testing agreed to a consecutive at-home BinaxNOW test. The BinaxNOW test returned negative in 69 of those students and positive in four students whereas the PCR test returned negative in 70 students and positive in three students. These data suggest that the at-home BinaxNOW test was at least as sensitive as the nasal PCR test.
All 91 of the symptomatic students agreed to have a lollipop PCR test performed. These results returned with 86 negatives and five positives compared to 88 negatives and three positives with the nasal PCR. These results indicate that the lollipop samples performed better than the nasal swabs. It is possible that the sample collection was more consistent with a lollipop swab as some students may have been reluctant to receive an effective nasal swab. Further, 92 percent of students preferred the lollipop swab to the nasal swab.
Overall, the results of this study provides proof of concept that a low-cost rapid test when repeated yields similar results to more expensive and less available PCR testing, and it assures that testing is available to all who need it.