Healthcare Hygiene magazine October 2023 | Page 8

By Rodney E . Rohde , PhD , MS , SM ( ASCP ) CM , SVCM , MBCM , FACSc

Most everyone has now at least heard about “ wastewater surveillance ” since it was a vital tool during the [ ongoing ] COVID-19 pandemic . The Centers for Disease Control and Prevention ( CDC ) launched the National Wastewater Surveillance System ( NWSS ) in September 2020 . CDC developed NWSS to coordinate and build the nation ’ s capacity to track the presence of SARS-CoV-2 , the virus that causes COVID-19 , in wastewater samples collected across the country .

CDC ’ s NWSS works with health departments to track SARS- CoV-2 RNA levels in wastewater . Wastewater surveillance has quickly become a primary tool for communities to act quickly to prevent the spread of COVID-19 . While bootstrap epidemiology , alongside public health and medical laboratory testing in healthcare will always be a part of our ability to respond to infectious disease outbreaks , NWSS is transforming independent local efforts into a robust , sustainable national surveillance system .

Wastewater is now a core component of infectious disease monitoring , providing a local or larger geographical snapshot of a variant-specific , community-representative picture of public health trends that captures previously undetected spread and pathogen transmission links . Remember , in the past the primary tool to detect an outbreak relied on classic epidemiology and laboratory testing of patient samples . In other words , one had to notice clustering of cases and ensure follow-up specimen collection and testing from individuals involved in the outbreak . This methodology requires extensive specimen acquisition , clinical testing , and sequencing coordinated across different sites and laboratories . This type of clinical surveillance is expensive , time-consuming , and subject to bias owing to disparities in public participation and frequency of testing and sequencing , which may limit outbreak preparedness and response by public health organizations , especially in underserved communities .

As you can imagine , while this works it can also mean missed opportunities to notice the genesis of a public health emergency .

How does wastewater surveillance work ?

When people are infected with a pathogen ( e . g ., SARS-CoV-2 , influenza , Respiratory Syncytial Virus , etc .) they can shed viral RNA ( genetic material from the virus or other microbe ) in their feces , and this RNA can be detected in community wastewater . Wastewater , also referred to as sewage , includes water from household , airport , hotel , or similar building use ( such as toilets , showers , and sinks ) containing human fecal waste , as well as water from non-household sources ( such as rain and industrial use ).

● Wastewater from a sewershed ( the community area served by a wastewater collection system ) is collected as it flows into a treatment plant .

● The samples are sent to environmental or public health laboratories for SARS-CoV-2 [ or other microbial ] testing .

● Health departments submit testing data to CDC through the online NWSS Data Collation and Integration for Public Health Event Response ( DCIPHER ) portal .

● The NWSS DCIPHER system analyzes the data and reports results to the health department for use in their COVID-19 response . The results are available to the public through CDC ’ s COVID Data Tracker .

How can we utilize wastewater surveillance ?

Ongoing research by scientists and others in public health prevention and preparedness have found that the examination of sewage can help detect SARS-CoV-2 , the virus that causes COVID-19 , in community settings prior to clinical surveillance via doctor ’ s offices or hospitals report to public health officials . However , at the present time while wastewater data can be an important early warning signal , it still should be used alongside other data .

● Wastewater surveillance data are most useful when used with other data . Wastewater data showing the percent change in virus levels should be used along with other data such as overall levels of the virus in wastewater , historical wastewater data for that location , geographical context ( for example , whether areas have high tourism or neighboring communities with increasing cases ), and clinical cases . Prevention efforts may impact changes in the virus wastewater levels .

● Early warning systems , such as wastewater surveillance , can detect small changes as a signal for early action . Importantly , when levels of virus in wastewater are low , a modest increase overall in the virus level can appear much larger as numbers are translated into percentages . Data showing changes from 1 unit to 2 units would be a percent change of 100 percent and the same can be said for a change from 500,000 units to 1 million units .

● More data over time can give better , more reliable trends . As with any data collection , one watches for sustained increasing levels of the virus in wastewater and uses this data to inform public health decisions . Correlation of other variables is often required .

Current research has also shown that positive correlation between wastewater surveillance and emergency department ( ED ) visit data for both influenza and RSV , along with the detection of these two pathogens in wastewater before increases in associated ED visits , suggests that wastewater surveillance might help supplement established clinical surveillance for these viruses .

The future of pathogen tracking is here . While the COVID-19 pandemic and subsequent global public health emergency of Mpox had many devastating outcomes , one silver lining has been the evolution of utilizing wastewater surveillance in national and global infectious disease outbreak detection . NWSS participation is expected to grow as health departments and public health laboratories develop their capacity

LEARN MORE HERE to coordinate wastewater surveillance , including epidemiology , data analytics , and laboratory support .

Rodney E . Rohde , PhD , MS , SM ( ASCP ) CM , SVCM , MBCM , FACSc , is the Regents ’ Professor , Texas State University System ; University Distinguished Chair & Professor , Clinical Laboratory Science ( CLS ); TEDx Speaker & Global Fellow – Global Citizenship Alliance ; Texas State Honorary Professor of International Studies ; Associate Director , Translational Health Research Initiative ; Past President , Texas Association for CLS .

8 october 2023 • www . healthcarehygienemagazine . com