Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Volume 32, Supplement –Summer 2026
SUPPLEMENT ISSUE
Supplement
Correlations between Wastewater Concentrations of Influenza A and Respiratory Syncytial Viruses and Clinical Laboratory Testing and Hospitalization Data, California, USA
, Madhura S. Rane, Marisa A.P. Donnelly, Lauren A. White, Cora Hoover, Monica Sun, Caroline Collins, Andrew Abram, Mariah Otstot, Joel Rojas, Cody Berkobien, Seema Jain, Duc J. Vugia, Wayne T.A. Enanoria, Linlin Li, Chad Below, Marlene Wolfe, Alexandria B. Boehm, Tomás M. León, Erin L. Murray, and Alexander T. Yu
Table 2
Kendall τ correlations between wastewater concentrations of influenza A virus and clinical laboratory testing and hospitalization data, California, USA*
| County | County-level correlations |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sentinel laboratory % positivity |
Sentinel laboratory no. positive specimens |
Laboratory-confirmed hospitalizations |
Sewershed-level correlations† |
|||||||||
| Sewershed | Population-level |
|||||||||||
| Overall | Maximum lag (range) | Overall | Maximum lag (range) | Overall | Maximum lag (range) | Overall | Maximum lag (range) | |||||
| Alameda |
0.56 |
0.61 (–2 to 15) |
0.62 |
0.66 (–3 to 12) |
0.67 |
0.67 (–14 to 12) |
Alameda |
0.6 |
0.61 (–6 to 6) |
|||
| Contra Costa |
0.53 | 0.6 (2–8) | 0.7 | 0.75 (–9 to 11) | 0.65 | 0.66 (–15 to 5) | Central Contra Costa | 0.72 | 0.73 (1–5) | |||
| Richmond |
0.63 |
0.66 (–11 to –3) |
||||||||||
| Marin |
0.57 |
0.57 (–10 to 21) |
0.61 |
0.62 (–8 to 16) |
0.5 |
0.53 (–16 to 12) |
Novato |
0.64 |
0.65 (–1 to 5) |
|||
| Sacramento |
0.55 |
0.57 (–10 to 11) |
0.69 |
0.7 (–12 to 10) |
0.65 |
0.66 (–15 to 9) |
Sacramento |
0.64 |
0.64 (–7 to 6) |
|||
| San Francisco |
0.57 | 0.58 (–8 to 14) | 0.69 | 0.69 (–9 to 12) | 0.56 | 0.57 (–15 to 18) | Oceanside | 0.6 | 0.63 (–7 to –3) | |||
| Southeast |
0.64 |
0.65 (–9 to 7) |
||||||||||
| San Mateo |
0.57 | 0.58 (–9 to 17) | 0.65 | 0.66 (–9 to 17) | 0.67 | 0.67 (–7 to 8) | San Mateo | 0.67 | 0.67 (–2 to 6) | |||
| Half Moon Bay | 0.66 | 0.67 (–3 to 3) | ||||||||||
| Silicon Valley |
0.62 |
0.62 (–2 to 5) |
||||||||||
| Santa Clara |
0.47 | 0.47 (–16 to 17) | 0.67 | 0.67 (–8 to 7) | 0.58 | 0.59 (–12 to 14) | Gilroy Morgan Hill | 0.6 | 0.6 (–3 to 1) | |||
| San Jose | 0.67 | 0.67 (–5 to 1) | ||||||||||
| Sunnyvale | 0.7 | 0.7 (–6 to 2) | ||||||||||
| Palo Alto |
0.66 |
0.66 (–1 to 5) |
||||||||||
| Santa Cruz | 0.54 | 0.61 (1–16) | 0.62 | 0.7 (3–16) | NA | NA | Santa Cruz City | 0.7 | 0.71 (–4 to –1) | |||
| Santa Cruz County |
0.75 |
0.78 (3–9) |
||||||||||
| Sonoma |
0.63 |
0.69 (2–22) |
0.71 |
0.75 (–3 to 16) |
0.64 |
0.65 (–11 to 6) |
Petaluma |
0.54 |
0.57 (3–7) |
|||
| Yolo | 0.57 | 0.59 (–3 to 19) | 0.53 | 0.55 (–8 to 20) | NA | NA | Davis | 0.52 | 0.53 (–6 to 1) | |||
*Kendall τ correlations between laboratory-confirmed influenza hospital admissions and wastewater influenza A concentrations from ELR, sentinel laboratories, and influenza A–positive specimen counts. Overall correlations represent Kendall τ correlation coefficients for the indicated datasets, calculated over the entire study period with no lags. Maximum lag correlations represent the maximum Kendall τ correlation coefficients for the indicated datasets when comparing lagged clinical datasets to wastewater datasets, including lags of –35 to 35 days. The range of maximum lagged τ (days) represents the range of days around a date of the maximum lagged correlation in which the lagged correlation coefficient is within 0.05 of the maximum τ value. The negative direction indicates that wastewater data is leading clinical data, and the positive direction indicates that wastewater data is lagging clinical data. ELR, electronic laboratory reported. †Data from mandatory ELR reporting calculated as no. positive specimens/100,000 population.