We classify overall respiratory risk as either normal, caution, high, or very high.

We use data from Wasco, Sherman, Hood River, and Gilliam counties to determine the overall risk category. The data we use to create the risk rating includes:

• How much COVID, flu, and RSV virus is found in the wastewater. Wastewater utilities in Hood River and The Dalles volunteer to send samples of the wastewater to an Oregon State University laboratory for testing. Anyone who has a virus will have pieces of virus in their poop, even if they don’t feel sick. Wastewater testing gives information about people with mild illness.

• Reports from the hospitals about how many people report to the Emergency Department with symptoms of flu, COVID, and RSV. This is an indicator of illness severity. Flu, COVID, and RSV strains can change from year to year. Strains that send more people to the hospital are more worrying.

• The percent of people tested at the hospital for flu, COVID, and RSV who are positive. Hospitals test lots of people all year for viruses to get a complete picture of everything making them sick. When viruses are not circulating, they get a lot of negative results. As a virus becomes more common, the percent of tests that are positive goes up. Public health has used this data to understand seasonal flu for many years.

All this data put together gives a good picture of when we go in and out of peaks, even though it does not count every person who is sick.

The CDC shares data on all of these measures publicly on this webpage. Oregon Health Authority shares wastewater monitoring data on this webpage and data from hospital testing on this webpage. It usually takes 1 or 2 weeks for the data to be reported. Even with that delay, our rating should still reasonably reflect the current risk in our area.

If you have more questions, please call 541-506-2600 or email disease@ncphd.org.