JN.1 COVID variant fuels surge in Bay Area cases for Christmas

COVID-19 cases and hospitalizations were rising rapidly in the Bay Area ahead of the holiday weekend, propelled by the nationwide surge of the newly identified JN.1 coronavirus variant. 

The omicron offshoot now constitutes about 44.1% of nationwide cases, doubling from 21.3% in the week ending Dec. 9, post-Thanksgiving, as per U.S. Centers for Disease Control and Prevention estimates released Friday.

Wastewater data from the CDC underscores this surge, indicating “very high” COVID-19 levels nationwide and a rising trend. Almost all Bay Area sewersheds show elevated virus levels, alongside a sharp increase in influenza activity and respiratory syncytial virus, or RSV.

With winter officially underway and indoor gatherings for the holiday season, public health officials anticipate even more cases in the new year. Dr. Manisha Patel from the CDC said, “Folks are traveling a lot more this season. They want to see their families, and all of that adds to the mix.”

Maria Van Kerkhove, the World Health Organization’s technical lead for COVID-19, warned that the currently circulating respiratory viruses will seize on the holiday season: “As people gather they spend more time indoors, especially if there’s poor ventilation, these pathogens that spread efficiently between people and through the air will take advantage.”

Nationwide, emergency department visits are surging, with adult admissions for COVID-19 increasing by over 16,000 in the past month. Influenza admissions also spiked by nearly 55,200 over the same period. California ranks among the states with the highest levels of respiratory virus activity in the country, with the combined illnesses responsible for nearly 5% of all emergency department visits as of Friday. Over the summer, that number had dipped below 0.7%.

Dr. Mandy Cohen, the director of the CDC, cautioned that that figure will likely increase. “We’re seeing RSV peak a bit sooner, but we do not believe we’re near yet at the peak of flu or COVID,” she told NBC News this week.

Cohen emphasized that COVID-19 remains the leading cause of severe ailments in the “tripledemic,” although not at levels seen in the first two years of the pandemic. “COVID is causing the most hospitalizations and deaths of all the viruses, but it’s not seeming to be more severe than what we were seeing last year at this time, which is good news,” she said.

The rapid spread of JN.1 prompted the World Health Organization to upgrade its classification to a “variant of interest” on Tuesday, its second-highest tier. Experts suggest that while the strain does not appear to cause more severe disease than previous variants, it spreads more easily between individuals.

“We are seeing JN.1 quickly become the dominant version of the COVID virus, which tells us it is more transmissible,” Cohen said. “The good news is, we don’t see an increase in severity.”

While neither organization tracks the evolution of symptoms, health officials have observed symptoms similar to illnesses caused by previous strains of the virus, with sore throat and congestion being the most common early signs. In severe cases, patients may suffer from shortness of breath, chest pain and discolored skin.

Despite a new COVID-19 vaccine designed to target the XBB.1.5 variant, only about 18% of adults and 8% of children aged 6 months and older have received the latest shots, available since September. According to a recent preprint study, these shots also demonstrate efficacy against the JN.1 variant.

Familiar mitigation measures, such as vaccination, handwashing, proper ventilation, mask-wearing and regular testing, remain effective. Dr. Bob Wachter, chair of the department of medicine at UCSF, emphasized the importance of vigilance.

“Given a moderate uptick in COVID over the past two months, I’m back to masking in crowded and poorly ventilated places, particularly when I don’t need to talk,” he said in a social media thread this week. “When I do mask, I always use an N95; I see no reason to wear a less effective mask.”

Cohen stressed the significance of considering those around you when implementing mitigation measures and encouraged individuals to stay home if sick.

“Are you going to Christmas with the grandparents? Are you going to be around work colleagues who are fighting cancer?” Cohen said. “Make sure that you as an individual are thinking not just about yourself.”

Reach Aidin Vaziri: [email protected]