The PA Department of Health tracks the prevalence of Covid, influenza, and RSV (Respiratory Syncytial Virus) through its PA Wastewater Surveillance System (PaWSS). This is a network of (currently) 27 Pennsylvania locations that do weekly sampling of wastewater to determine levels of the viruses causing those three conditions. The resulting data helps healthcare workers and the public determine whether an outbreak is occurring.

The data for the sampling location nearest Kendal is showing a striking increase in Covid. It is not showing an increase in the other two kinds of virus.

If you go to the PaWSS website (https://www.pa.gov/agencies/health/programs/environmental-health/pawss) and select West Chester Site 1 (the sampling location nearest us), you will find a map and graph similar to the one below.

This map and graph, from the Pennsylvania Wastewater Surveillance System, shows that Covid virus levels spiked to the “very high” category for the week ending September 13.

The latest readings are considered “very high”. Since monitoring at that location began more than two years ago, there have only been about half a dozen weeks when levels have been higher than they are right now.

At other nearby sampling locations (West Chester Site 2, Media, and Chester, for example) there is no similar spike, so it is quite local.

The PaWSS reports a number called “WVAL” for each weekly sample. This is a calculation of the virus level found in wastewater relative to a baseline value. Any WVAL above 7.8 is considered “very high”, so the latest value, 13.08, reported for the week ending September 13, is certainly very high.

Since the samples are taken on Saturdays, and the values are reported the Monday nine days later, we don’t really know what the current situation is. During the nine days after the sample was taken, the level of Covid could have gotten worse, or the outbreak could have largely subsided. We won’t have information about that until next Monday.

In the meantime, be careful. I notice that the Covid warning chart outside Resident Care is showing “green”, which reassures me that the nearby outbreak is not having a significant impact on us.

Update 9-29-25: It seems to have subsided. Today, the WVAL number for Covid at West Chester Site 1 is 3.98, which is considered only “moderate”.