Summary: Week of 7/15/24

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 28 (July 13) 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 in the risk reports.

Biobot’s national wastewater network showed very low national concentrations of influenza A & B and RSV during week 28, while SARS-CoV-2 concentrations continued to increase. Nationally, major clinical metrics remained low for influenza and RSV in week 27, 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 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 28. 

Influenza

Nationally, influenza A and B concentrations remained very low in week 28.  

Clinical data showed that the illness burden due to influenza remained quite low in week 27. 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 27. 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 28. The national average SARS-CoV-2 wastewater concentration is now 555 copies per mL. 

Clinical metrics showed signs of increasing COVID-19 activity in week 27. Test positivity increased, currently at 11.0%. COVID-NET reports that the COVID-19 hospitalization rate is currently at 2 per 100,000 persons. Deaths due to COVID-19 slightly increased in week 27 and currently represent 0.8% of all deaths in the US.

Regional

The South

RSV: In the South, RSV wastewater concentrations remained stable and very low during week 28.  

Influenza: Influenza A and B concentrations held steady at very low levels in the South during week 28. Clinical data continues to confirm that the disease burden due to influenza remains low—all Southern states remained in the minimal ILI activity level through week 27.  

COVID-19: SARS-CoV-2 wastewater concentrations increased significantly in the South during week 28, at 565 copies per mL. Georgia and Tennessee, the two Southern states in COVID-NET, experienced a decrease in the COVID-19 hospitalization rate in week 27. 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 28.  

Influenza: Influenza A and B wastewater concentrations remained stable and very low in the Midwest in week 28. Clinical data continues to show a low influenza illness burden in the Midwest—all states remained in the minimal ILI activity level in week 27. 

COVID-19: SARS-CoV-2 wastewater concentrations increased significantly in the Midwest during week 28, at 561 copies per mL. Michigan, Minnesota, and Ohio are Midwestern states in COVID-NET. In week 27, all three states experienced a decrease in hospitalization rates, which remained low overall.

The Northeast

RSV: In the Northeast, RSV wastewater concentrations remained stable and very low during week 28.

Influenza: Influenza A concentrations held steady and remained very low in the Northeast during week 28. After a brief influenza B uptick in the Northeast, concentrations came back down in week 28. In week 27, all Northeastern states remained in the minimal ILI activity level. 

COVID-19: SARS-CoV-2 wastewater concentrations increased in the Northeast during week 28, currently at 637 copies per mL. Connecticut, Maryland, and New York are Northeastern states in COVID-NET. In week 26, hospitalization rates increased in Connecticut and New York and decreased in Maryland. Hospitalization rates remained low in all three states.

The West

RSV: RSV wastewater concentrations remained stable and very low in the West during week 28.  

Influenza: Influenza A and B concentrations held steady and remained very low in the West during week 28. During week 27, all Western states were at the Minimum ILI activity level. 

COVID-19: During week 28, SARS-CoV-2 wastewater concentrations increased in the West, currently at 442 copies per mL. California, Colorado, New Mexico, Oregon, and Utah are Western states in COVID-NET. Hospitalization rates continued to increase in California in week 27 and are now close to what they were in early December at 6.4 per 100,000 persons. Hospitalization rates decreased in Colorado, New Mexico, Oregon, and Utah in week 27 and remained low.

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Footnotes: 

Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through July 13, 2024 (MMWR week 28). 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 6, 2024 (MMWR week 27).