Efforts to use sewage as an affordable early warning indicator for COVID-19 infections are being delayed because the Department of Health won’t share information with the University of Hawaii and the City and County of Honolulu.
“We want to get more data from DOH to help us validate our model and it has not been easy,” said Tao Yan, a civil and environmental engineering professor from the University of Hawaii who oversees the wastewater testing lab.
Honolulu is one of many municipalities across the world that is testing sewage for traces of the virus. Experts are still working to understand how the novel coronavirus behaves in different scenarios, but testing sewage shows promise as a cost-effective indicator of how widespread the virus is in a large community and as a way to identify areas where people are sick before they show symptoms.
The University of Hawaii has been testing nine samples, one from every public wastewater treatment plant on Oahu, for 10 weeks now and the virus has been detected in almost every sample. These preliminary results aren’t surprising to experts because the number of confirmed cases has been climbing for weeks.
But Yan said his team cannot determine if its data is accurate if it can’t compare wastewater results to results from nasal swabs, which are collected by DOH.
“We’ve only been given aggregate data and we want results from specific zip codes around the sewage treatment plants,” Yan said.
Josh Stanbro, Honolulu’s chief resilience officer, said DOH has not told him why it won’t share the zip code data. Stanbro has been working with other municipalities around the country who are also testing wastewater, and analyzing zip code data from nasal swabs has been key for those municipalities to validate their wastewater data.
“This is not something that is unique to here,” he said.
Yan and Stanbro said until they get the zip code data, they can’t release information about the amount of the virus found at certain wastewater treatment plants because the analysis could be incorrect or misleading.
“This should be a team approach because we’re all fighting the same virus.” – Bill Hicks, Kailua Neighborhood Board member
When the City and County of Honolulu joined an international movement to test sewage for COVID-19 in May, it hoped to make the data available on its COVID-19 website and use it to promptly warn communities about outbreaks. Scientists say the virus can often be detected in a person’s feces days before they start showing symptoms.
A robust sewage treatment program could guide public health workers to areas of the island where people are infected but have not started showing symptoms yet, Stanbro said.
That program was initially delayed because BioBot, the company originally analyzing Honolulu’s sewage, was experiencing a major backlog. The county sent in four weeks of samples on May 1, but didn’t get the results back for weeks.
“That defeats the whole purpose of testing the sewage,” Stanbro said at the time.
“$300 per test to monitor a population of several hundred thousand is the cheapest and most effective way to monitor the entire island,” Stanbro said. “If we can get the science right.”
If Yan’s team can get the science right Stanbro said dorms, prisons and senior care facilities could easily monitor the health of their communities.
“The best application of this technology would be for congregate living,” he said. “Instead of having to test everybody all the time with very expensive individual tests, you could test the wastewater inexpensively.”
Data from the testing surge would help Yan’s team calibrate its wastewater analysis.
Cory Lum/Civil Beat
Yan said his lab has been consistently returning results within three days. Workers from the Department of Environmental Services drop off samples on Monday afternoon and the UH lab sends results to the county on Thursday morning.
Yan’s team is using three different processes to measure the amount of the virus in the samples. The different processes give different results. Yan said if he could compare the wastewater results against granular zip code data from DOH, it would be easier for his team to determine which testing process is most accurate for the island.
Adding to the challenge are new discoveries about how the amount of the virus an infected person sheds in their feces changes over time.
“That seems to be the hallmark of this virus: as we know more, we know less.” — Tao Yan, UH professor
“It’s really not as straightforward as we thought,” Yan said. “Using the data to achieve early detection is still the goal but we’re not there yet.”
Other labs have been struggling with the same scientific quandaries. With funding from the National Science Foundation, Yan has been working with a group of researchers and universities from around the country to determine the most accurate way forward.
“That seems to be the hallmark of this virus: as we know more, we know less,” he said.
All the uncertainty is frustrating for Bill Hicks, chairman of the Kailua Neighborhood Board.
When he couldn’t find results online he reached out to Stanbro, but was disappointed.
“I don’t want to pile onto DOH but the general public is not getting data that we need to make intelligent decisions and keep everyone safe,” he said. “This should be a team approach because we’re all fighting the same virus.”
Stanbro is still holding out hope that DOH will share zip code data. Instead of once a week, the county is considering collecting sewage samples every day during the two week federally-funded testing surge so Yan’s team has more data points and the wastewater analysis can be even more accurate.
“We want to be able to strike an agreement where we can get access to the data and determine once and for all: Does this work?” he said. “If it does great … we’ll use it as a tool. If it doesn’t, we can discontinue it and focus on other areas.”
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