Summary: Week of 7/22/24

We continue to monitor the 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 29 (July 20) also indicate that influenza activity remains low in the four US regions. We want to highlight are 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 9 out of the 13 states with positive dairy herds (Texas, New Mexico, Kansas, Idaho, Ohio, North Carolina, Iowa, Wyoming, and Oklahoma), among several other states across the country. 
• Our current assays do not distinguish between infections in humans and infected animals that are shed into the wastewater system. 

This situation is rapidly evolving and our team will continue to closely monitor H5N1. We will provide any additional information as it becomes relevant or available via Twitter and here in the risk reports.

Biobot’s national wastewater network showed very low national concentrations of influenza A & B and RSV during week 29, while SARS-CoV-2 concentrations continued to increase. Nationally, major clinical metrics remained low for influenza and RSV in week 28, while metrics for COVID-19 remained elevated. 

The Bottom Line: The summer COVID-19 surge we are currently experiencing continues to increase in most parts of the country. Our recommendations to remain healthy are the same as they were in the winter: 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 29.

Influenza

Nationally, influenza A and B concentrations remained very low in week 29.

Clinical data showed that the illness burden due to influenza remained quite low in week 28. 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 1.4%. FluSurv-NET reports that the influenza hospitalization rate per 100,000 persons also remains very low, currently at 0.1 in week 28. 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 continued to increase during week 29. The national average SARS-CoV-2 wastewater concentration is now 616 copies per mL.

Clinical metrics continued to show signs of increasing COVID-19 activity in week 28. Test positivity increased, currently at 12.6%. COVID-NET reports that the COVID-19 hospitalization rate increased and is currently at 2.5 per 100,000 persons. Deaths due to COVID-19 held steady in week 28, and currently represent 0.9% of all deaths in the US.

Regional

The South

RSV: In the South, RSV wastewater concentrations remained stable and very low during week 29.  

Influenza:  Influenza A and B concentrations held steady at very low levels in the South during week 29. Clinical data continues to confirm that disease burden due to influenza remains low – all Southern states remained in the Minimal ILI activity level through week 28. 

COVID-19: SARS-CoV-2 wastewater concentrations held steady in the South during week 29, currently at 585 copies per mL. Georgia and Tennessee are the two Southern states in COVID-NET. In good news, Georgia experienced a decrease in the COVID-19 hospitalization rate in week 28. Tennessee, however, experienced a slight increase. Overall, the hospitalizations rates in both states are low, and similar to what they were in the fall.

The Midwest

RSV: RSV concentrations remained stable and very low in the Midwest during week 29. 

Influenza: Influenza A and B wastewater concentrations remained very low in the Midwest in week 29. Clinical data continues to show low influenza illness burden in the Midwest – all states remained in the Minimal ILI activity level in week 28.

COVID-19: SARS-CoV-2 wastewater concentrations increased in the Midwest during week 29, currently at 685 copies per mL. Michigan, Minnesota, and Ohio are Midwestern states in COVID-NET. In week 28, the hospitalization rates in Michigan and Ohio held steady while the rate in Minnesota slightly decreased. Hospitalization rates remained low overall. 

The Northeast

RSV: In the Northeast, RSV wastewater concentrations remained stable and very low during week 29.

Influenza: Influenza A and B concentrations held steady and remained very low in the Northeast during week 29. In week 28, all Northeastern states remained in the Minimal ILI activity level.

COVID-19: SARS-CoV-2 wastewater concentrations slightly increased in the Northeast during week 29, currently at 650 copies per mL. Connecticut, Maryland, and New York are Northeastern states in COVID-NET. In week 28, hospitalization rates held steady in Connecticut, and decreased in Maryland and New York. Hospitalization rates remained low in all three states.

The West

RSV: RSV wastewater concentrations remained stable and very low in the West during week 29.

Influenza: Influenza A and B concentrations held steady and remained very low in the West during week 29. During week 28, all Western states were in the Minimal ILI activity level.

COVID-19: During week 29, SARS-CoV-2 wastewater concentrations increased in the West, currently at 549 copies per mL. California, Colorado, New Mexico, Oregon, and Utah are Western states in COVID-NET. Hospitalization rates finally began decreasing in California in week 28, but remained elevated at 5 hospitalizations per 100,000 persons, which is similar to what the state experienced in late-November, 2023. Hospitalizations rates decreased in New Mexico, Oregon, and Utah, and held steady in Colorado in week 28. Hospitalization rates remained low in these four Western states.

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Footnotes: 

Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through July 20, 2024 (MMWR week 29). 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 July 13, 2024 (MMWR week 28).