OK, this is unique. An MIT startup has come up with a way to analyze wastewater and estimate the percentage of people in the community with COVID. Measuring the virus concentration in a liter of sewage seems doable — translating this to the percentage of people in the community that are infected is what they themselves describe as an imprecise estimate. And how they even calibrate is something I have not yet figured out.
The results they get are in line with what others are seeing with more traditional anti-body tests however:
there are approximately 15 times the number of positive cases as there are confirmed, positive tests
Anyways, this gets points for originality.
www.wdel.com/…
After New Castle County Public Works Stormwater and Environmental Program Manager Mike Harris teamed up with Massachusetts Institute of Technology's startup Biobot Analytics, officials studied samples of waste matter at a pretreatment center for the sewer system. According to estimations provided following bacterial testing at the plant, the county appeared to have a staggering number of novel coronavirus COVID-19 cases--15,200 in a catchment area that serves about 100,000 individuals in an area of the county.
"I want to emphasize it is an imprecise estimate, but their imprecise estimate is that there are approximately 15 times the number of positive cases as there are confirmed, positive tests, Meyer said during a Zoom call with reporters Thursday. "Again, emphasize this is a new technology, it's unconfirmed, but they have been doing it in various areas throughout the country, and our result is somewhat comparable...to the other areas around the country."
They note that with this approach they circumvent privacy issues, since the data being collected is already anonymized.
The attached PDF says that the startup has reached capacity at 100 treatment facilities in almost 25 states. They claim to be working to increase their capacity. I was looking at their website — their first product was to analyze opiate usage in a community by analyzing wastewater.
If we go back to the original company, we get a better idea about what it is that they are claiming:
medium.com/…
Why sewage analysis shows a higher number of cases than confirmed cases from individual testing.At this time, our prevalence estimates are a back of the envelope exercise and there’s much work to be done to improve accuracy. Beyond our own technical limitations, there are possible explanations why sewage is giving a higher number of infected people, as compared to confirmed cases:
- People with mild symptoms may not go to the hospital, or get tested,
- There is growing evidence that Covid-19 could have a large asymptomatic population,
- Limited access to clinical testing, and
- A lag in reporting confirmed cases.
Next steps to make our Covid-19 case estimation more accurate.Our next step to make our Covid-19 case estimation model more accurate is to model the person-to-person variability in SARS-CoV-2 shedding in stool. Our team is already in conversation with other academic groups tackling this issue. Kudos to academic collaboration!
