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Nationwide WastewaterSCAN August 2026 Update

Hi Everyone,

This newsletter contains updates on the WastewaterSCAN program with wastewater samples analyzed by the lab through August 31, 2026. Below you will find information on the program in terms of participating partners, review of targets being measured, as well as current wastewater categories (low, medium, high) of the infectious disease targets.

Best,

WastewaterSCAN Team

Participating Plants

>38 million people covered across 40 states

WWSCAN site coverage map as of August 2026

Infectious Disease Target Review

Currently monitoring a suite of Respiratory, Gastrointestinal and Outbreak Pathogens of Concern

The methods for our assays are in the public domain and links for these are provided at the end of the newsletter.

In mid-July 2026, blaNDM (an antibiotic-resistance gene) and Mycobacterium tuberculosis (TB) were added to the pathogen panel WWSCAN monitors for in early July 2026.

Program Publications

Recent publications, factsheets, FAQs, and more!

WWSCAN Published Body of Work document:

WWSCAN FAQs:

WWSCAN Factsheets and Guidance Documents can be found here.

Wastewater Category Logic

As a reminder, WWSCAN categorizes sites based on Levels + Trends + Frequency of detection. We adopted this methodology back in 2023 as a way to clearly communicate what wastewater is telling us about community disease circulation. The wastewater categorization helps us quickly understand if the recent measurements for a infectious disease fall into a low, medium, or high category and are determined based on a combination of the following variables:

  • Trends tell us how concentrations are changing  (⬆up,⬇down, ━ no change) over the last 21 days
  • Levels tell us whether concentrations are relatively lower or higher (based on national tertiles over last 365 days)
  • Frequency of detection indicates how often a pathogen is detected in wastewater (important for pathogens that are not commonly detected)

There are 3 Archetypes for WWSCAN Pathogens:

  • Pathogens that are commonly detected (regardless of season - includes SARS-CoV-2, Norovirus, Rotavirus)
  • Seasonal pathogens (rarely detected outside of season/outbreaks - includes Influenza A + B, RSV, HMPV, EV-D68)
  • Pathogens that are not commonly detected (rare regardless of season - includes C. auris, HepA, H5 influenza marker, Measles, Mpox clade Ib, Mpox clade II, Parvovirus, West Nile Virus)

*Categories are not currently being calculated for H1 and H3 Influenza markers, Adenovirus Group F, blaNDM, or Mycobacterium tuberculosis.

To learn more about WWSCAN's categorization logic, please see: https://data.wastewaterscan.org/about/#8

COVID-19

SARS-CoV-2 concentration in wastewater and sequencing for variants

SARS-CoV-2 N gene RNA was detected in ~90% of samples in August 2026 (for reference the detection rate in July 2026 was 75%). The median SARS-CoV-2 concentration in August 2026 was up ~163% compared to July 2026. SARS-CoV-2 concentrations are still lower across all regions compared to this time last year (i.e. 2025 summer wave) but are continuing to trend upwards. SARS-CoV-2 concentrations in the South and West regions have surpassed concentrations observed during the 2025-2026 winter peak.

SARS-CoV-2 (SC2) detection rate plot over the last 24 months for the WastewaterSCAN network. Positive detection rates are shown in red and Non-detection rates are shown in light blue. Note SC2 detection rates have been increasing since July 2026.

Below is the population weighted average SARS-CoV-2 N gene concentrations (normalized by PMMoV) is shown in black from all participating WWSCAN sites across the country over the last 365 days. Evident in this is plot is an increasing in SARS-CoV-2 concentrations starting mid-June 2026. SARS-CoV-2 concentrations are continuing to climb across all regions. In past years we have seen the summer SARS-CoV-2 wave start around mid-June so we are seeing a later start to this years' summer wave.

Nationally, SARS-CoV-2 is in the 'HIGH' category with aggregated measurements showing high concentrations and an upward trend over the last 3 weeks. As a reminder WWSCAN uses a 365 day look-back period to determine wastewater categories.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA. In the top right corner is a zoomed in plot of SARS-CoV-2 contractions over the last 3 months, which shows an increase across all regions starting in July 2026.

Sequencing of SARS-CoV-2 from wastewater is available for a select number of individual sites. The sequencing protocol is available on protocol.io. The plots below show the relative proportions of different variants inferred from sequencing the entire genome of SARS-CoV-2. Results are based on sequencing of 2 samples per week, combined to provide a weekly value.

Sequencing data is also available in aggregate across all sites in WWSCAN with sequencing data. That plot is shown below and also suggests that XFG (shown in orange) is the most abundant variant across all sites at 48.2% followed by BA.3.2 (shown in blue) at 9.3% and LF.7 (shown in yellow) at 9%. The hashed lines indicate weeks with lower confidence sequencing results.

SARS-CoV-2 sequencing data from the last 12 months. This plot includes data through the week of August 22, 2026. The hashed lines indicate lower confidence sequencing results.

Other Respiratory Pathogens

Influenza A & B, Respiratory Syncytial Virus, Human metapneumovirus, EV-D68 & Parvovirus

Influenza A (IAV) RNA was detected in ~17% of samples in August 2026 (for reference the detection rate in July 2026 was 9.3%). The median IAV RNA concentration across all sites in August 2026 was below the limit of detection. Currently, most sites are seeing consistent non-detects for IAV.

Below is the population weighted average IAV concentrations (normalized by PMMoV) is shown in black from all participating WWSCAN sites across the country over the last 365 days. Evident in the plot are IAV wastewater concentrations peaking in early January 2026 across all regions. Nationally, Influenza A is in the 'LOW' Wastewater Category due to not being in seasonal onset.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

H1 Marker in Influenza A (IAV) The H1 marker in Influenza A was detected in ~7.3% of samples in August 2026 (for reference the detection rate in July 2026 was ~3%). The H1 median concentration across all sites in August 2026 was below the limit of detection. You can find a heat map of positive H1 detections here. This past flu season (2025-2026) we saw very low detections of the H1 influenza marker compared to the H3 influenza marker.

Plot shows last 12 months of data for the WWSCAN national aggregate of the H1 marker. Note the y-axis scale shows normalized wastewater concentrations for the H1 influenza marker.

H3 Marker in Influenza A (IAV) In August 2026, the H3 marker in influenza A was detected in ~1.8% of samples (for reference the detection rate in July 2026 was ~2%). The H3 median concentration across all sites in August 2026 was below the limit of detection. During the 2025-2026 respiratory virus season, the H3 marker appeared to increasingly drive the higher influenza A concentrations. You can find a heat map of positive H3 detections here.

Plot shows last 12 months of data for the WWSCAN national aggregate. Note the y-axis scale shows normalized wastewater concentrations for the H3 influenza marker.

H5 Marker in Influenza A (IAV) As of August 31, 2026, WWSCAN sites across 28 states (AK, AR, CA, CO, CT, DE, FL, IA, ID, IL, KS, KY, MA, ME, MD, MI, MN, NC, NE, NH, NJ, NV, SD, TN, TX, UT, VA and VT) have seen positive detections for the H5 marker in influenza A. Since prospective monitoring began, 1,107/54,324 samples have tested positive (~2% detection rate). In August 2026, there were 5 positive H5 marker detection (all in TX). You can find a heat map of positive detections here.

Map shows the location of all WWSCAN sites that have had at least 1 positive detection(s) of the H5 marker in Influenza A since prospective monitoring began in May 2024. Map shows data through August 2026.

In January 2026 WWSCAN started calculating a wastewater category for the H5 influenza marker. The H5 marker is now assigned to the 'Pathogens that are not commonly detected ' category logic. Nationally, the H5 influenza marker is in the 'NOT DETECTED' category due no recent detections.

Below is a plot of positive H5 influenza marker sample counts (by week) since monitoring began in May 2024. Evident in the plot are minimal positive detections of the H5 influenza marker since the wave observed Oct 2024 - May 2025.

Plot shows the weekly count of positive wastewater H5 influenza marker detections since WWSCAN began monitoring for H5. Evident in the plot is minimal detections (<10 detections/week) since May 2025.

Influenza B (IBV) RNA was detected in ~2.8% of samples in August 2026 (for reference the detection rate in July 2026 was ~5%) . The median IBV RNA concentration across all sites in August 2026 was below the limit of detection. Currently, most sites are seeing consistent non-detects for IBV.

Below is the population-weighted average IBV RNA concentrations (normalized by PMMoV) is shown in black from all participating WWSCAN sites across the country over the last 365 days. Nationally, Influenza B is in the 'LOW' Wastewater Category due to not being in seasonal onset.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

Respiratory syncytial virus (RSV) RNA was detected in ~8.4% of samples in August 2026 (for reference the detection rate in July 2026 was ~7.3%). The RSV RNA median concentration across all sites in August 2026 was below the limit of detection. As a reminder, during last years respiratory virus season the WWSCAN network hit seasonal onset for RSV in early December 2024 and peaked in late January/early February 2025. We saw a slower start to the RSV wastewater wave this past respiratory virus season (2025-2026) compared to last year (2024-2025). Currently, most sites are seeing consistent non-detects for RSV.

Below the population-weighted average RSV RNA concentrations (normalized by PMMoV) is shown in black from all participating WWSCAN sites across the country over the last 365 days. Nationally, RSV is in the 'LOW' Wastewater Category due to no longer being in seasonal onset.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

HMPV (human metapneumovirus) RNA was detected in ~9.8% of samples in August 2026 (for reference the detection rate in July 2026 was ~16%). The median HMPV RNA concentrations across all sites in August 2026 was below the limit of detection. HMPV concentrations began decreasing mid April 2026 and most sites are seeing consistent non-detects for HMPV.

Below is the population weighted average HMPV RNA concentrations (normalized by PMMoV) shown in black from all participating WWSCAN sites across the country over the last 365 days. Evident in the plot HMPV concentrations over the 2025-2026 respiratory virus seasons began decreasing mid-April. Nationally, HMPV is in the 'LOW' Wastewater Category due to no longer being in seasonal onset.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

Enterovirus D68 (EV-D68) RNA was detected in ~17% of samples collected in August 2026 (for reference the detection rate in July 2026 was ~3%). The median concentration across all sites in August 2026 was below the limit of detection. Nationally, EV-D68 is in the 'LOW' Wastewater Category and not in seasonal onset.

EV-D68 detection rate plot since WastewaterSCAN began monitoring in Sept 2023. Positive detection rates are shown in red and Non-detection rates are shown in light blue. Note EV-D68 detection rates showed a significant increase in August 2026.

Below is the population-weighted average EV-D68 RNA (normalized by PMMoV) shown in black from all participating WWSCAN sites across the country over the last 24 months. In this plot you can see elevated EV-D68 concentrations across all regions during the 2024-2025 season. EV-D68 concentrations in the Midwest (shown in red) rose again in mid August 2025 before coming down in November 2025, and concentrations in the West (shown in blue) rose in late September 2025 and have come down since the beginning of January 2026. Recently we have seen more positive detections of EV-D68 in samples across the Midwest and South.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

Parvovirus (Parvo) DNA was detected in ~5% of samples from all WWSCAN sites in August 2026. In March 2026 WWSCAN started calculating a wastewater category for Parvo. Parvo is now assigned to the 'Pathogens that are not commonly detected ' category logic. Nationally, Parvo is in the 'LOW' category due to limited detections.

The chart below shows each WWSCAN plant in New Jersey as rows, and days as columns (labeled at the bottom axis). White indicates no samples, blue is a non-detect for Parvo DNA and red is a detection for Parvo DNA. Evident in the plot is limited detections at some sites and frequent detections at other sites.

Heat map of positive Parvovirus detections (in red) across sites in New Jersey participating in WWSCAN over the last 3 months. Blue indicates non-detect.

Gastrointestinal Pathogens

Norovirus GII, Human Adenovirus Group F, & Rotavirus

Norovirus GII (HuNoV GII) RNA was detected in 100% of samples analyzed in August 2026. The median Norovirus concentration in August 2026 was down ~12% compared to July 2026. Last year, we saw Norovirus concentrations start to increase in early October 2024 and peak early February 2025. While we saw a slower start to the winter Norovirus wave this year (2025-2026), the pattern is similar to what we observed during the 2023-2024 winter Norovirus wave.

Below is the population weighted average HuNoV GII RNA concentrations (normalized by PMMoV) shown in black from all participating WWSCAN sites across the country over the last 365 days. Nationally, Norovirus is in the 'LOW' Wastewater Category with aggregated measurements showing low concentrations and no trend in the last 21 days.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

Human Adenovirus Group F (HAdV-F) RNA was detected in 100% of samples from all WWSCAN sites in August 2026. The median HAdV-F concentration in August 2026 was down ~33% compared to July 2026.

Plot shows last 12 months of HAdV-F for the WWSCAN national aggregate since monitoring resumed. Note the y-axis scale shows normalized wastewater concentrations for HAdV-F.

As a reminder, we are not currently calculating wastewater categories for HAdV-F. In order to calculate wastewater categories we need a longer time series of data to examine trends and levels.

Rotavirus (Rota) RNA was detected in ~73% of samples from all WWSCAN sites in August 2026. Rotavirus concentrations peaked in April 2026 and have been decreasing ever since, which is what we would typically expect to see this time of year.

Below is the is the population weighted average Rota RNA concentrations (normalized by PMMoV) shown in black from all participating WWSCAN sites across the country over the last 365 days. Nationally, Rotavirus is in the 'MEDIUM' Wastewater Category with aggregated measurements showing medium concentrations and no trend in the last 21 days.

Midwest states: IA, IL, IN, KS, MI, MN, NE, OH, SD, WI. Northeast states: CT, MA, ME, NH, NJ, NY, PA, VT. Southern states: AL, AR, DE, FL, GA, KY, LA, MD, MS, NC, TN, TX, VA, and WV. Western States: AK, CA, CO, HI, ID, NV, UT, WA.

Other Pathogens of Concern

blaNDM, Candidozyma auris, Hepatitis A, Measles, Mpox clade Ib, Mpox clade II, Mycobacterium tuberculosis, and West Nile Virus

blaNDM RNA/DNA- New Delhi metallo-beta lactamase (blaNDM) data went live to the WWSCAN dashboard in early July 2026. blaNDM is an antibiotic-resistance gene that makes bacteria resistant to nearly all beta-lactam antibiotics by producing NDM, an enzyme that inactivates these antibiotics. It is extremely versatile in inactivating a broad class of antibiotics and its high genetic mobility. The assay we run will detect blaNDM variants 1-15, 17-31, and 33-47 (Chavda et al., 2016).

As we just started measuring this new pathogen, we are not currently calculating wastewater categories for blaNDM. In order to calculate wastewater categories we need a longer time series of data to examine trends, levels and differences in prevalence across regions. For now, this data can only be viewed in chart mode on the data dashboard. For more information on blaNDM please see: Frequently Asked Questions on WWSCAN Measurements of blaNDM nucleic acids in Wastewater Solids.

Candidozyma auris (C. auris) DNA was detected C. auris DNA in ~3.9% of samples from all WWSCAN sites in August 2026. Nationally, C. auris is in the 'LOW' category due to limited detections.

The chart below shows plants in Indiana as rows, and days as columns (labeled at the bottom axis). White indicates no samples, blue is non-detect for C. auris DNA and red is detect for C. auris DNA. Evident in the plot below is most sites have few to no detections of C. auris.

Heat map shows last 6 months of C. auris wastewater data from WWSCAN sites in Indiana. Blue indicates non-detect.

Hepatitis A (HepA) RNA was detected Hep A RNA in ~6.7% of samples from all WWSCAN sites in August 2026. Nationally, HepA is in 'LOW' category due to limited detections.

The chart below shows each WWSCAN plant in Texas as rows, and days as columns (labeled at the bottom axis). White indicates no samples, blue is a non-detect for Hep A RNA and red is a detection for Hep A RNA. Evident in the plot below is some sites have sporadic detections while others have few to no detections of HepA.

Heat map shows last 6 months of Hepatitis A wastewater data from WWSCAN sites in Texas. Blue indicates non-detect.

Measles (MeV) RNA - In mid-May 2025, WWSCAN began prospectively monitoring for MeV. Since prospective monitoring began, 237/30,602 samples have tested positive (0.77% detection rate). In August 2026, there were 5 positive detections of MeV in wastewater samples (1 in CA, 1 in GA, 1 in ME, and 2 in UT). Nationally, MeV is in the 'NOT DETECTED' category due to no recent detections.

Since monitoring began, 53 sites across 25 states (AK, CA, CO, CT, FL, GA, IA, ID, IL, IN, KS, KY, MD, ME, MI, MN, NE, NJ, NV, NY, PA, TX, UT, VA, and VT) have had at least 1 positive detection of MeV in wastewater samples collected. Below is a map of sites with MeV detections in wastewater since prospective monitoring began.

The WWSCAN program began monitoring for measles in wastewater start mid May 2025. This map only shows data from the sites/states that are covered by the WWSCAN program.

Mpox clade Ib DNA - In mid December 2024, WWSCAN began prospective monitoring for Mpox clade Ib. You can find a heat map of the Mpox clade Ib data here. In August 2026, there were no positive detections of Mpox clade Ib. Nationally, Mpox clade Ib is in the 'NOT-DETECTED' category due to no recent detections.

Mpox clade II DNA - There was only 1 positive detection of Mpox clade II in August 2026. Nationally, Mpox clade II is in the 'NOT-DETECTED' category due to no recent detections.

Mycobacterium tuberculosis (TB) RNA/DNA - Mycobacterium tuberculosis (TB) data went live to the WWSCAN dashboard in early July 2026. Globally, TB cases have increased in recent years after having previously fallen. There were more than 1 million deaths from TB in 2024. Monitoring TB nucleic-acids in wastewater can help shed light on TB infections across sewersheds in the WWSCAN network.

As we just started measuring this new pathogen, we are not currently calculating wastewater categories for TB. In order to calculate wastewater categories we need a longer time series of data to examine trends, levels, and frequency of detection. For now, this data can only be viewed in chart mode on the data dashboard. For more information on TB please see: Frequently Asked Questions on WWSCAN Measurements of Mycobacterium tuberculosis (TB) nucleic acids in Wastewater Solids

West Nile Virus RNA - There were 10 positive detections of WNV in August 2026 (1 in AL, 1 in CA, 4 in KS, 2 in KY, 1 in OH, and 1 in UT). Nationally, WNV in the 'LOW' category due to limited detections.

WWSCAN protocols and methods

Protocols (Pre-analytical methods and SARS-CoV-2 analytical methods including controls):

Peer-reviewed publications provided WWSCAN methods: 

Questions about WastewaterSCAN?

If you have questions about the website or anything else, please email: wwscan_stanford_emory@lists.stanford.edu

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