Play Live Radio
Next Up:
Available On Air Stations
Watch Live


COVID-19 wastewater surveillance shows San Diego's case surge is slowing

San Diego is starting to come off the current surge in COVID-19 cases.. KPBS Health Reporter Matt Hoffman says that’s according to wastewater data from across the region.

COVID-19 wastewater data now shows that the record spread of the virus in San Diego is beginning to fall.

"We’re coming off the surge for sure," said UC San Diego Professor Rob Knight. "However, it’s possible that cases will continue to rise or maybe peak around now."

Knight leads the project that has been analyzing San Diegans sewage from the Point Loma treatment plan over the last two years. He said wastewater is a leading indicator of the virus’ spread, with data typically three weeks ahead of confirmed cases.


"What we've seen over and over again is peaks in the wastewater are followed by peaks in cases, peaks in hospitalizations," Knight said. "Although we were off that highest peak — we’re still at very still levels in the wastewater at this point."

RELATED: UCSD reports 'unprecedented' spike in wastewater COVID viral load

Using wastewater data researchers predicted the record spike in cases ahead of the holidays. Knight said although we appear to be off the current peak, the amount of COVID-19 found in wastewater is about 10 times worse than in mid-December when they warned of record surges.

"The reason the wastewater is a leading indicator is just because you get infected in the gut before you get infected in the airways," Knight said. "And so as a result we see these things in the wastewater."

The decreasing numbers are welcome news for hospitals that are up against dwindling capacity, but with thousands of cases still being reported daily, we are not out of the surge yet.


"It’s good news for the community, but remember we still have to be careful right now," Knight said.

Samples are picked up from the Point Loma plant about four times a week. They are also taken from across the UC San Diego campus. The omicron variant makes up the majority of the current waste samples. Knight said with the strain being more contagious, it likely contributed to a sharper surge in cases this winter when compared to last.