COVID-19 Testing in Wastewater - P/A Test Kit in Urgent Need
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It has been found that people who are infected with COVID-19 shed the virus in their stool even before they show any symptoms. This generates a necessity of establishing a wastewater surveillance program of testing wastewater periodically and mapping the results to the number of infected people by predictions. I am invited to participate in such a program today for the Borough of Indiana. As the fall semester is approaching, the Borough and the University are worried about the outbreak in a second wave as students are returning to campus from all over the country. In today's Zoom meeting, I proposed to collect time-series of raw wastewater samples from the residence halls and academic buildings, and then to test the presence of the COVID-19 virus in the samples. With sufficient numbers of binary data on presence and absence, an approach of using statistical tools combined with the data on the numbers of people who are using the buildings will be able to give projections on the number of infected people. This sounds promising. However, the problem is how to quickly do the testing with the raw wastewater samples? There is no test kit available so far. According to this EPA webpage, such standard method of concentrating and quantifying SARS-CoV-2 with molecular and live, or infectious, assays in wastewater is still under development. With regard to the non-standard methods, the MedRxiv has this paper, which has not gone through a peer-review process. The method introduced by this paper involved processes of wastewater pasteurization (at 60 deg C for 1-1.5 hrs for virus inactivation), 0.2 um membrane filtration (40 mL filtrate is stored at 4 deg C for further analysis), filtrate centrifugation (precipitated viral particles collected and resuspended), RNA extraction, and then quantitative PCR (qPCR). The process is labor-intensive. For individual's home uses, it is just useful for each individual to know the binary data - presence or absence of virus. Quantitatively giving the copies of RNA segments is not that meaningful for each home, despite that it is indeed important to know the proprietary models (by BioBot Analytics Inc - the affiliation of the paper's authors) of mapping the copies of RNA segments from wastewater samples to the actual number of infected people coupled with confirmed clinical cases as validation data points on the larger scale at the Borough or the University. With that said, qualitative methods for COVID-19 testing in wastewater are highly desirable. If there are any P/A test kits available on the market, I will buy it.
Published from: Pennsylvania US
Liked by: Andy Tang