The Hawaii Department of Health’ s inaugural wastewater surveillance report for COVID-19 compares the concentration levels of coronavirus in wastewater with clinical COVID cases, using data provided by Biobot Analytics of Cambridge, Mass., as part of a national wastewater surveillance program.
The DOH says the report, published last week, shows COVID-19 cases have been on the decline since early June, with omicron subvariant BA.5 still the dominant strain in Hawaii.
“Data from wastewater testing aligns with other data sets,” said State Laboratories Division Administrator Edward Desmond in a news release. “Results from COVID-19 tests taken by individuals show case counts have dropped since June. This is consistent with data in the Wastewater Report which shows concentrations of SARS-CoV-2 have declined since June. Genome sequencing shows BA.5 is the most common subvariant in Hawaii. The Wastewater Report also supports that finding.”
Going forward, the DOH plans to publish wastewater surveillance reports every two weeks using Biobot’s data.
The Centers for Disease Control and Prevention contracted Biobot in May to collect and analyze wastewater samples from hundreds of sites across the United States, including Hawaii, for levels of SARS-CoV-2, the virus that causes COVID-19.
The CDC considers wastewater monitoring a valuable public health tool alongside other surveillance methods because people infected shed viral RNA in their feces, regardless of whether they have symptoms or not. Consequently, the data can reveal infected people who never got tested as well as those who tested positive at home.
Changes in wastewater infection trends, on average, happen four to six days before changes in clinical cases, CDC said, so serve as an early warning system. Additionally, sequencing of wastewater samples, which Biobot does, offers information on what variants are circulating in the community.
But wastewater data also has limitations, in that it cannot precisely predict case counts, and it will not capture what is going on in communities not connected to wastewater treatment plants.
The DOH coordinates weekly collection of samples from 15 wastewater treatment sites in Hawaii for the national program. The samples are sent to Biobot for analysis. Biobot now provides test results about a week after samples are collected.
The results are available via CDC’s online wastewater metric map. With permission from individual sites, Biobot also presents results on its own website, biobot.io/data.
The DOH began receiving full wastewater results in late July, Desmond said, and will now present that data in a biweekly report.
Desmond said Hawaii is fortunate to be part of the national program at no cost to the state, with a relatively quick turnaround time. Meanwhile, the DOH will continue to develop its own COVID-19 wastewater surveillance capabilities.
“If we do it ourselves, we don’t think we could do it much quicker” than the national program, Desmond said. “The good thing about this system is it enables us to compare results by our own testing methods with those from the contract laboratory, so that’s what we’re doing right now and we’re making sure we’re doing this testing in the best way possible.”
The DOH said this will also give staff time to work toward wastewater testing for other pathogens, such as monkeypox, as well as in the long-term, antibiotic resistance markers.
The CDC said Biobot’s existing contract for the national coronavirus wastewater testing program lasts through January.
Additionally, the state is continuing to conduct whole genome sequencing on hundreds of human test samples collected statewide, which is published in a variant report every two weeks.
As fall gets underway, epidemiologists are keeping a wary eye on new immune-evading subvariants spreading in other countries, such as BA.2.75.2 and BQ.1, as well as XBB, which has shown resistance to antibodies developed from previous infections and vaccinations. If these variants crop up in Hawaii, Desmond said, they will likely be detected through wastewater monitoring and genome sequencing of clinical samples.
