SEATTLE — Some signs of a late-summer COVID-19 wave are beginning to emerge in Washington after months of low transmission levels. But researchers and public health officials aren’t too worried yet.
The state’s COVID levels have remained fairly steady all summer, though there have been a few bumps and declines in hospitalizations — and many Washingtonians have largely embraced the return to mass gatherings and eased their indoor masking routines. But cases are on the rise again nationwide, and hospital admissions have increased about 12% in the last week, according to the Centers for Disease Control and Prevention.
In Washington, reported cases — which state health officials say are likely undercounts — were at about 18.2 cases per 100,000 people in mid-July, compared to a height of 1,828 cases per 100,000 during January 2022’s omicron surge.
Rates of hospitalizations and deaths are also nowhere near as high as they’ve been during previous waves of COVID, at about 1.9 hospitalizations per 100,000 and 0.2 deaths per 100,000, according to the state Department of Health’s data dashboard.
There are some recent metrics that show an increase in transmission could be on its way to the state, but it’s too soon to know further details about severity or timeline, said Pavitra Roychoudhury, a research assistant professor of laboratory medicine and pathology at the University of Washington.
Her lab noticed the uptick earlier this week, when looking over the newest batch of positive COVID tests from UW Medicine’s hospitals. The lab usually tests about 500 samples per day, and has recorded a positivity rate between 1% and 3% all summer, Roychoudhury said Wednesday.
On Tuesday, about 22 of 443 samples, or about 5%, returned positive for COVID.
“It’s not very large,” she said. “I don’t want to over-index it. But that’s just the most recent data point we have.”
Local public health departments, including King County’s, have also noted small upticks in reported cases in the past week.
For a better idea of what COVID trends could be ahead, Roychoudhury and her team have also turned to wastewater data, which can track SARS-CoV-2 particles in sewage and act as a longer-term early warning system for upcoming waves of infection.
“If you look at wastewater curves versus the number of cases in previous waves, you can see quite clearly that wastewater increases precede increases in cases,” she said. “And wastewater levels are on the rise across the country.”
According to the state’s wastewater data, the average levels of SARS-CoV-2 concentration have started rising at several treatment plants in recent weeks, including at the Brightwater and West Point facilities in King and Snohomish counties.
Because similar trends are emerging in other parts of the country, particularly the southeastern U.S., Roychoudhury said she’s more likely to start masking up and taking greater safety precautions, particularly when traveling.
“If I’m taking a domestic flight, chances are I’m going to be sitting next to someone in one of those areas [where COVID levels are increasing],” she said. “It’s about knowing what’s out there, but ultimately people are going to take that and combine it with their own assessment of individual risk.”
She encouraged the public to look at local and state COVID data when debating what mitigation efforts to reintroduce into daily life, like masking, distancing, frequent testing and staying home when sick. The introduction of another COVID booster shot, or a second bivalent booster, by the end of September should also help provide protection against severe illness, she said.
“I’m not surprised that we’re seeing this rise in cases,” Roychoudhury said. “It’s not unexpected to see a small wave in the summer. But it’s not dramatic in Washington just yet.”