Welcome to 2023-2024 season's respiratory surveillance recap, where we’ll share insights from the...
Respiratory Virus Risk Reports
Comprehensive Insights for COVID-19, Influenza, and RSV
COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of June 24, 2024
Throughout the respiratory season, we analyze wastewater for the presence of respiratory syncytial virus (RSV) and influenza virus (types A and B). Together with COVID-19, these three pathogens are outsized contributors to our seasonal respiratory illness burden. In this data series, we’ll guide you through the wealth of data we’ve gathered from our Biobot Network of national sampling sites, aiming to shed light on emerging trends in respiratory virus activity and community viral load. Our goal is to equip you with information to make informed decisions.
Data Note: Samples are collected from participating locations, and processed by our lab team on a rolling basis. Each point on the figure represents the weekly average concentration, from Sunday – Saturday (corresponding to the MMWR week), aligned to that week’s Saturday.
Contributors
Marisa Donnelly, PhD
Public Health Partnerships Epidemiologist
Previous Risk Reports
Summary: Week of 6/24/24
We continue to monitor the rapidly evolving H5N1 influenza virus situation. As we do, a quick reminder that Biobot’s influenza A assay detects the H5N1 influenza subtype, which is an influenza A virus, but does not distinguish between the different subtypes of influenza A (e.g., H5N1 vs H1N1).
Thankfully, we still have not seen large, widespread increases in influenza A concentrations. Data through week 25 (June 22) also indicate that influenza activity remains low in the four US regions. We want to highlight some important points about the role of Biobot’s wastewater data in understanding the current circulation/risk of H5N1:
- At this point, we cannot determine if any upticks we’ve observed are due to seasonal influenza A virus or if H5N1 could have played a role.
- Biobot is currently testing for influenza A in 8 out of the 12 states with positive dairy herds (Texas, New Mexico, Kansas, Idaho, Ohio, North Carolina, Iowa, and Wyoming), among several other states across the country.
- Our current assays do not distinguish between human infections and infected animals shed in the wastewater system.
This situation is rapidly evolving, and our team will continue to monitor H5N1 closely. We will provide any additional information as it becomes relevant or available via Twitter and in the risk reports.
Biobot’s national wastewater network showed very low national influenza A & B and RSV concentrations during week 25. SARS-CoV-2 held steady in week 25 and appears to be at somewhat of a plateau, although levels remain elevated. Nationally, major clinical metrics remained low for influenza and RSV in week 24, while metrics for COVID-19 remained elevated. The percentage of outpatient visits due to influenza-like illness (ILI) remains below the national baseline of 2.9%, currently at 1.6%. All states have a minimal ILI activity level; overall, the clinical respiratory illness burden remains low.
The Bottom Line: As we head into summer, we continue to keep our eyes on two things: 1. SARS-CoV-2 concentrations, which suggest that we are in an early-summer wave, and 2. The evolving H5N1 situation, which thankfully does not currently pose a significant threat to human health. Closely monitoring both these situations is essential to protecting human health. Our recommendations to keep yourself and loved ones healthy remain the same: if you feel unwell, minimize contact with others, consider wearing a mask in crowded areas, and stay current with vaccinations and boosters.
National Outlook
RSV
Nationally, RSV concentrations remained very low in week 25.
Influenza
Nationally, influenza A and B concentrations remained very low in week 25.
Clinical data showed that the illness burden due to influenza remained quite low in week 24. The percentage of outpatient visits for influenza-like illness (ILI) – typical in flu, RSV, and COVID-19 patients – held steady and remains below the national baseline of 2.9%, currently at 1.6%. FluSurv-NET reports that the influenza hospitalization rate per 100,000 persons also remains very low, currently at 0.1 in week 24. These metrics are at levels we would typically expect for this time of year and indicate low influenza activity.
COVID-19
Wastewater data show that COVID-19 activity and community viral load held steady during week 25. The national average SARS-CoV-2 wastewater concentration is now 358 copies per mL.
Clinical metrics continued to show some signs of increasing COVID-19 activity in week 24. Test positivity increased, currently at 6.6%. COVID-NET reports that the COVID-19 hospitalization rate held steady, currently at 1.3 per 100,000 persons in week 24. Deaths due to COVID-19 held steady and currently represent 0.7% of all deaths in the US.
Regional
The South
RSV: In the South, RSV wastewater concentrations remained stable and very low during week 25.
Influenza: Influenza A and B concentrations held steady at very low levels in the South during week 25. Clinical data continues to confirm that the disease burden due to influenza remains low—all Southern states remained at a minimal ILI activity level through week 24.
COVID-19: SARS-CoV-2 wastewater concentrations increased in the South during week 25 at 307 copies per mL. Georgia and Tennessee are the two Southern states in COVID-NET, an enhanced hospitalization surveillance system. Georgia’s COVID-19 hospitalization rate decreased in week 24, while Tennessee’s held steady. Overall, COVID-19 hospitalization rates in both states remained low.
The Midwest
RSV: RSV concentrations remained stable and very low in the Midwest during week 25.
Influenza: Influenza A and B wastewater concentrations remained stable and very low in the Midwest in week 25. Clinical data shows a low influenza illness burden in the Midwest—all states remained in the minimal ILI activity level in week 24.
COVID-19: SARS-CoV-2 wastewater concentrations held steady in the Midwest during week 25, currently at 313 copies per mL. Michigan, Minnesota, and Ohio are Midwestern states in COVID-NET. In week 24, hospitalization rates remained very low in all three and appear to be either decreasing or holding steady.
The Northeast
RSV: In the Northeast, RSV wastewater concentrations remained stable and very low during week 25.
Influenza: During week 25, Influenza A and B concentrations held steady and remained very low in the Northeast. In week 24, all Northeastern states remained at the minimal ILI activity level.
COVID-19: SARS-CoV-2 wastewater concentrations increased in the Northeast during week 25, at 449 copies per mL. Connecticut, Maryland, and New York are Northeastern states in COVID-NET. In week 24, Connecticut experienced a small increase in the COVID-19 hospitalization rate, while rates decreased in Maryland and held steady in New York. Hospitalization rates are still low in all three states.
The West
RSV: RSV wastewater concentrations remained stable and very low in the West during week 25.
Influenza: Influenza A and B concentrations held steady and remained very low in the West during week 25. During week 24, all Western states were at the Minimum ILI activity level.
COVID-19: During week 25, SARS-CoV-2 wastewater concentrations declined again in the West, currently at 301 copies per mL. California, Colorado, New Mexico, Oregon, and Utah are Western states in COVID-NET. Hospitalization rates appeared to increase in California and Oregon in week 24, while rates in Colorado, New Mexico, and Utah either held steady or decreased. Of these Western states in COVID-NET, California’s hospitalization rate is the highest, currently at 3.7 per 100,000 persons.
Footnotes:
Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through June 22, 2024 (MMWR week 25). Clinical data on testing, hospitalizations, and emergency department visits for RSV, influenza, and COVID-19 are from the Centers for Disease Control and Prevention. Updates to clinical data for RSV, influenza, and COVID-19 are through June 15, 2024 (MMWR week 24).