Optimizing Disease Detection and Containment Through a Waste-Before-Case Approach

by Megan Diamond – Manager, Health Initiative, The Rockefeller Foundation & Aparna Keshaviah – Senior Statistician, Mathematica

When a new public health threat emerges – like the highly infectious Omicron variant of the SARS-CoV-2 virus – detecting the first case before there has been widespread community transmission can be like searching for the proverbial needle in a haystack.

Yet wastewater testing is a tool optimized to do just that. People infected with SARS-CoV-2 shed the virus when they go to the bathroom – including asymptomatic people who may not even know they are infected. The sewers then act like large magnets, aggregating the virus particles found in feces into centralized locations where researchers and public health officials can take samples and detect the virus, sometimes before a clinical case emerges. In fact, over the past week, multiple cities in the United States were able to detect Omicron in the wastewater before a clinical case was identified.

As vaccinations plateau and testing declines, public health officials are looking for alternative means to passively collect data that provides real-time insights for decision-making. Wastewater testing does exactly that, at the fraction of the cost of clinical testing.

Wastewater-based epidemiology (WBE) is not a new field. Decades of evidence have shown that WBE is an effective tool for detecting outbreaks of pathogens like poliovirus and typhoid, with the potential for much more. And although it has been used in several countries, including in the United States, to monitor for SARS-CoV-2, ongoing questions remain on how to best interpret and use data derived from wastewater for pandemic response.

For example, wastewater data is inherently messy, and more work is needed to reliably distinguish signal from noise in viral concentrations collected from wastewater to detect a rising threat. It’s also unclear how wastewater data should be synthesized with other local public health data—such as clinical case counts and reports of Covid-like symptoms—to provide officials with a more holistic measure of Covid-19 risk in their community. The potential of sequencing viral RNA in wastewater remains underexplored, too.

The creation of the Wastewater Action Group (WAG) – which includes leading researchers and public health officials in Atlanta (Emory University), Houston, Louisville, Tribal Nations (Arizona State University) and Tulsa  – is one of the ways that The Rockefeller Foundation and PPI are supporting cities across the US to translate wastewater data into action.  Together, this network of partners is refining wastewater sampling, testing, and sequencing protocols; developing metrics and strategies for wastewater-based risk communication; and expanding wastewater testing to underserved populations that are not connected to centralized wastewater treatment plants.

The impact of these efforts are being seen in real time:

  • In Houston, Texas, partners at the Houston Health Department and Rice University detected Omicron in the wastewater before a confirmed clinical case and subsequently sequenced positive samples from school children residing in the service areas of the wastewater treatment plan.
  • In Louisville, Kentucky, partners at the University of Louisville and Louisville Metro Dept. Public Health & Wellness detected Omicron in the wastewater before a confirmed case in Jefferson County. Through close collaboration with the State of Kentucky, they can now do targeted sequencing within the community.
  • In Tulsa, Oklahoma, partners at the Tulsa Health Department and University of Oklahoma saw an increase in influenza A virus concentration was detected in the wastewater, enabling quick communication to the public.

PPI recently met the growing need for rapid peer-to-peer learning by hosting an urgent meeting focused on wastewater sequencing in light of the emergence of Omicron. More than 30 wastewater testing leaders attended and since then, more than half have either reached out to someone they met on the call or adapted their response plans based on information shared during the session.

PPI is also dedicated to hearing from end users of public health data. Through a collaboration with Mathematica, The Rockefeller Foundation is fielding a nationwide survey among public health leaders.

The results of the survey could inform the development of decision-making tools for public health departments and help policymakers determine how they can best support wastewater surveillance across the country.

At present, no single data source provides a full picture of COVID-19. The most widely reported data—clinical case counts—overlook large swaths of the population that lack access to quality health care. As a result, the first signs of an outbreak are often detected weeks, if not months, after the emergence of a new threat. Wastewater testing is a way to fill this critical data gap.

The world can no longer wait for fragmented, delayed, and biased data. By supporting the development and scaling of wastewater-based epidemiologic tools and knowledge, PPI seeks to boost the capacity of public health officials to detect infectious disease outbreaks and prevent the next pandemic.

Free Health Screening – A Service to our Community’s Health

Last weekend I had the privilege of supervising University of Miami Miller School of Medicine students at a free public health screening in Pompano Beach, Florida.  The screening was sponsored by the medical school, with the assistance of community leaders, and held in a local public school. The program organization, recruitment of student and faculty volunteers and management of the program was undertaken and implemented by the students. It is one of several programs of this nature undertaken by these students in Dade, Broward and Palm Beach County Florida.

Stations were set up to screen for vital signs, weight, body mass index, glucose and cholesterol. A women’s center with breast exam, cervical pap smears and dexa heel bone density tests was available. There was an ophthalmology station with physicians from Bascom Palmer Eye Institute. A dermatology section was available with fellows from the world class dermatology program at the University of Miami. Pediatric and neurology sections were available as well as mental health screening. The program was enhanced by the participation of the Broward County Health Department and numerous other community organizations.

After the patients rotated through each station they exited at a checkout area manned by students and faculty. The students organized all the data for the patient participants, explained what their exam findings meant and established mechanisms for the patients to receive follow-up care in the Public Health setting.

This was the fifth year I have participated as a voluntary faculty member. I noticed the patients were younger, sicker and presenting with more social and health problems than in previous years. Several times during the screenings, the fire rescue squad was called to transport individuals to the hospital because their initial entry into the health system detected a serious enough condition to require immediate hospitalization. The patients were proud, hard working American citizens of all races, colors and creeds who were devastated by the recession with loss of jobs and health insurance benefits.  For many, this screening was their first trip to the doctor in years. Although well received, this screening was the most rudimentary of safety nets available for this community from the health care field.

Some 225 patients were examined in an eight hour period. I was proud of the students for a job well done. After it was over I went home and took time to read the local newspaper. There was a front page article about how our new governor had just proposed a budget which cuts all funding for primary medical care at Public Health Facilities. I wondered how many of those patients we referred for follow-up to Public Health facilities would now have to wait until next year’s screening program to obtain it?

I wish those Tea Party and righteous cost cutting conservative politicians and our governor had spent the day interviewing, examining and counseling the patients I saw today. I wonder how they would react to a frightened fifteen year old hoping to get a pregnancy test and too poor to afford a store bought test?  I wonder what they would say to a 5th grade teacher who had lost her home to foreclosure and couldn’t afford to pay an ophthalmologist in the private setting to check her glaucoma. I wonder what Governor Scott and the Tea Party would say to a 50 year old former triathlon performer who lost his construction and landscape business during the recession, lost his health insurance, gained forty pounds due to the stress of life and was now unemployed, diabetic and hypertensive with no access to health care?

It’s easy to pontificate about the flaws of health care reform until you sit down with the sickest and most vulnerable and realize they are no different than you and I.