North Bay infectious disease experts voice optimism and caution over new COVID-19 strains – The Santa Rosa Press Democrat

Most of the COVID-19 cases Dr. Gary Green is treating these days on an outpatient level are related to crowded events and travel the kinds of things Americans do in greater numbers as summer arrives.

For the highly infectious SARS-CoV-2 coronavirus, that can translate to spreading infections.

Green, a Sutter Health infectious disease expert, says hes seeing a steady flow of cases but not a lot, and severe symptoms requiring hospitalization are uncommon.

Increasing herd immunity, greater outdoor activity spurred by warmer weather and an elderly population that has dialed in protective measures are all contributing to a lull in cases, Green said.

But new COVID-19 subvariants are threatening to ramp up viral transmission this summer and especially in the fall and winter.

KP. 2, the most prolific of the so-called FLiRT subvariants, and currently the most dominant subvariant in the U.S., is a fourth or fifth generation strain of the omicron variant. Its a descendant of omicrons JN.1 strain.

In less than two months, between late March and early May, KP. 2 infections went from 4% to about 28% in the United States, according to the federal Centers for Disease Control and Prevention.

Green said as with previous subvariants of SARS-CoV-2, the virus that causes COVID-19 illness, KP. 2 has mutated spike proteins that allow it to more efficiently attach to respiratory epithelium, which protect against inhaled pathogens and irritants.

Unfortunately, thats part of the natural evolution of these subvariants, he said.

We expect these viruses to be a little bit more efficient in their contagiousness and their transmission and their attachment, Green said.

But the good news is this is mainly in the upper respiratory tract, where you feel like (you have) the head cold, and not as much in the lower respiratory tract where you feel like you have pneumonia, he said.

These don't make the virus any more dangerous, Green added. So we don't expect more severe cases. But it might be just slightly more contagious.

Green said the current vaccine does appear to offer some protection against the new variants.

Dr. Tanya Phares, Sonoma Countys health officer, echoed Greens comments regarding the subvariants. Despite increased transmissibility, these mutations dont appear to result in more severe disease, she said in an email.

Phares said that between late March and early May, eight cases of FLiRT subvariants have been genetically sequenced. The FLiRT subvariants are descended from the JN.1 subvariant, which is still the dominant strain in Sonoma County and the state, health officials said.

In Napa County, the most prevalent subvariants since April have been KP. 2 at 7%, KP. 3 at 4% and KP. 1.1 at 3%, according to county health officials.

Dr. Michael Vollmer, regional hospital epidemiologist for Kaiser Permanente, said the most recent FLiRT mutations are not unexpected and follow a pattern of viral evolution that takes place every three to six months as the virus circulates globally.

The virus is still constantly looking for pathways to replicate itself, Vollmer said, adding that todays mutations, though related, look very different than what was circulating a year ago or two years ago.

But what were not seeing at this juncture is any increase in severe illness, he said. Unlike in 2021, we don't think we're going to see some big jump in emergency room or hospital admissions through the summer.

Vollmer said predicting what will happen in the fall and winter is more difficult.

Its important for people to understand that COVID-19 is not going anywhere and while the overall impact is not as severe as it once was, the virus still poses danger to those over 65 or people who are severely immunosuppressed, he said.

Those that keep up to date with vaccinations are going to do better, Vollmer said. People, particularly those who are in those vulnerable categories, should make sure that they're getting up-to-date vaccinations, they could consider getting repeat doses.

Vollmer said he expects vaccine makers and federal regulators will be convening this month to discuss another update to the COVID-19 vaccine for the fall and winter seasons.

The next two to four weeks this summer could see an increase in COVID-19 cases, but its not likely to have a big impact on the health care system, he said.

Dr. John Swartzberg, an infectious disease expert at UC Berkeley, said omicrons JN.1 strain had been dominant in the United States up until about two months ago, when JN.1 subvariants such as KP. 2 began gaining ground.

The current vaccine which became available last October targets an omicron subvariant known as XBB. 1, Swartzberg said, adding that KP. 2 was more transmissible than JN. 1, which itself was more transmissible than XBB. 1.

SARS-CoV-2 continues to evolve, just as it has throughout the pandemic, by discovering new ways to evade the host immunity, he said.

But Swartzberg pointed out there is little evidence that KP. 2 and the latest JN.1 subvariants cause more severe disease.

The other good news, he said, is that the current vaccine does offer some protection.

Swartzberg said last month the World Health Organization recommended the fall vaccine be directed against JN.1. He said he expects the U.S. Food and Drug Administration will at least take that step in recommendations.

Theyll either follow the WHO and recommend the vaccine (target) JN.1 or they recommend it against KP. 2, the most prominent of the FLiRT variants, Swartzberg said.

The good news is it only takes a couple of months to really produce enough vaccine to vaccinate everybody, he said.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @pressreno.

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North Bay infectious disease experts voice optimism and caution over new COVID-19 strains - The Santa Rosa Press Democrat