COVID-19 summer surge hits North Bay

North Bay is facing a spike in COVID-19 infections this summer, driven in part by the highly contagious FLiRT subvariant and low vaccination rates, local health experts said Wednesday.

Sonoma County Health Officer Dr. Tanya Phares said the current “summer surge” of COVID-19 infections, while a well-known trend during the pandemic, has surpassed that of the previous year.

“The current summer surge has surpassed 2023, but not 2022,” Phares said. “That’s a national trend, but it looks like we’re seeing that in Sonoma County as well.”

According to the latest local sewage surveillance data for SARS-CoV-2, which causes COVID-19 disease, this year’s summer wave appears to be happening earlier than last year.

On June 27, the “composite” level of COVID-19 detected at the Santa Rosa, Petaluma and Windsor wastewater sites was 56% of the highest historical level during the pandemic.

On the same date last summer it was 8 percent. For Santa Rosa alone the level on June 27 was 61 this summer and 8 percent on that date last summer.

Local detection of COVID-19 in wastewater has been rising since late April. Phares said it’s unclear whether COVID-19 infections will peak earlier this summer or if numbers will continue to rise.

“It’s possible that it will peak earlier or that it will continue to rise, but it’s very difficult to predict what it’s going to do,” Phares said. “We’ve seen different variations with each peak over time, so we’re dealing with something different each time.”

Phares said national trends, as well as those in Europe, point to continued spread of the so-called FLiRT subvariants, which are descendants of the omicron variant. Nationally, the dominant FLiRT subvariant is KP.3, and KP.3.1.1 is expected to grow quite rapidly in the United States and Europe, she said.

According to Phares, the current increase is worrying, given the low vaccination rate in the region.

The overall vaccination rate — the share of the population that is up to date on their COVID-19 vaccinations — is 23%. Even the most vulnerable age group, those 65 and older, has a vaccination rate of just under 56%.

The overall, current vaccination rate in Napa County is nearly 21%; and 51% for people 65 and older.

Vaccine and pandemic fatigue are likely partly to blame for the current summer surge and low vaccination rates, according to Dr. Gary Green, an infectious disease expert at Sutter Santa Rosa Regional Hospital.

Green said Sutter is experiencing a “summer peak” in cases, meaning most COVID-19 patients are being treated on an outpatient basis.

He noted that there has also been a “slight increase” in COVID-19 hospitalizations and emergency room visits, “but I wouldn’t call that an increase.”

Green suspects the increase is partly due to increased travel in the summer, waning immunity and people simply taking fewer precautions.

According to him, the summer heat waves across the country may also cause more people to stay indoors and have close contact with each other.

“I think the heat wave has brought everyone indoors, to the malls, to indoor stores … because it’s just too hot,” he said. “I think that crowding is going to spread the viral transmission.”

Green said that currently 30% of all nasal swabs taken in outpatient clinics are positive. For comparison, he said, flu season typically begins when swab positivity rates are 10%.

Green said in the emergency department, 16% of all COVID-19 tests are positive.

According to Phares, the number of deaths from COVID-19 has remained low but stable and poses a particular threat to the most vulnerable groups, including frail older people and people with chronic diseases and weakened immune systems.

Since the start of the year, there have been 39 COVID-19 deaths, she said, which equates to fewer than 10 per month.

“The message is that we have to be careful and we have to make efforts to increase vaccination rates to protect ourselves, but also to limit the spread of the disease and prevent it from mutating,” she said.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or [email protected]. On Twitter @pressreno.

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