California’s strongest summer coronavirus outbreak in years is still surging, and an unusual mid-summer mutation may be part of the reason.
Experts say there could be many culprits behind the worst summer spike in infections since 2022. Smoke from a series of harrowing heat waves and devastating wildfires has kept many Californians indoors, where the disease is more likely to spread. Most adults have also moved on from their last exposure to the coronavirus or their last vaccine shot, meaning they are more susceptible to infection.
But changes in the virus have also broadened the scope of the surge.
Of particular concern is the rise of a highly contagious subvariant known as KP.3.1.1, which is so contagious that even those who have escaped infection throughout the pandemic People can get sick too.
“COVID-19 is very common right now,” said Dr. Elizabeth Hudson, regional chief of infectious diseases for Kaiser Permanente’s 16-hospital health care system in Southern California.
COVID-19 hospitalizations are increasing but remain below the peaks of the past two summers, likely thanks to some residual immunity and widespread use of anti-COVID drugs like Paxlovid.
The World Health Organization has warned that coronavirus infections are rising around the world and expressed concern about the possible emergence of more severe variants.
“In recent months, many countries have experienced surges in COVID-19 regardless of season, including during the Olympics,” said Dr. Maria Van Kerkhove, WHO’s COVID technical lead.
Among them was 27-year-old American sprinter Noah Lyles, who struggled in Thursday’s 200m final and took bronze after winning gold in the men’s 100m final. Lyles collapsed after the game with shortness of breath and chest pain and was taken away in a wheelchair.
“It definitely affects my performance,” he said of the disease, estimating that he feels “90 to 95 percent” more energetic.
The rate of reported positive coronavirus tests has been rising for weeks – exceeding 10% globally and over 20% in Europe. In California, the positive coronavirus test rate was 14.3% in the week ended August 5, exceeding last summer and winter peaks and up from 10% a month ago.
There were already signs of a typical U.S. mid-year wave in May, as a pair of new coronavirus subvariants — KP.2 and KP.1.1, collectively known as FLiRT — began to make a splash, replacing the dominant strain over the winter. Already started in advance.
But by July, a descendant strain, KP.3.1.1, became apparent.
“KP.3.1.1 is extremely contagious and has a greater ability to escape immunity. This situation suddenly appeared in the summer,” said Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco. “
Kaiser Permanente Southern California has seen an increase in cases, and “looking at the CDC data… KP.3.1.1 is really what’s driving this particular surge,” Hudson said. “We’re definitely at a much higher level than we were last summer.”
Anecdotally, Hudson said, some infected people reported “actually quite a lot of pain — really tiredness for the first two days.”
She said people may think their symptoms are just allergies, but “it could be COVID-19. So we just encourage people to keep testing.”
However, an initial negative test doesn’t necessarily mean you’re out of the woods. Officials recommend repeated testing up to five days after symptoms appear to be sure.
California has now reported “very high” levels of the coronavirus in its wastewater for four consecutive weeks, according to data released Friday by the U.S. Centers for Disease Control and Prevention. The previous five weeks had seen virus levels at “high” levels.
California only recorded “high” coronavirus levels in wastewater for eight weeks last summer, and never reached “very high” levels. In the summer of 2022, coronavirus levels in California wastewater were at “high” or “very high” levels for 16 weeks.
“Compared to the same time last year, fewer people have been vaccinated this year,” Chin-Hong said. “That means, especially older people, they are not equipped to deal with this virus.”
According to the CDC, 44 states have “high” or “very high” levels of the coronavirus in wastewater. Five states and the District of Columbia have “moderate” levels, and North Dakota has no data.
The CDC says coronavirus infections are “increasing” or “likely to increase” in 32 states, including California; economic conditions are “stable or uncertain” in seven states and the District of Columbia; and Connecticut “may be increasing” “Decline”; Hawaii and Nevada are “Decline”. Eight states have no estimates.
In Los Angeles County, coronavirus levels in wastewater jumped to 54% of last winter’s peak in the 10 days ending July 27. A week ago, coronavirus levels in wastewater were only 44% of last winter’s peak.
Los Angeles County reported an average of 479 coronavirus cases per day in the week ending Aug. 4, double the number five weeks earlier. The number of cases is an underestimation and reflects only testing done at medical facilities, not self-testing done at home.
In Santa Clara County, the Bay Area’s most populous county, coronavirus levels are high in all sewers, including in San Jose and Palo Alto.
Coronavirus-related hospitalizations and emergency room visits are also increasing. In the week ending August 3, Los Angeles County hospitals had an average of 403 coronavirus-positive patients per day. That number is double what it was five weeks ago, but still about 70% of last year’s summer peak and one-third of the 2022 summer peak.
In the week ending Aug. 4, 4% of emergency room visits in Los Angeles County were classified as coronavirus-related, more than double the number seven weeks earlier. Last summer’s peak was 5.1%.
“We have some people who are very sick from COVID-19. These people tend to be pretty severely immunocompromised,” said Hudson.
UCSF has also seen an increase in the number of patients hospitalized with coronavirus infections. As of Friday, the number had reached 28, compared with fewer than 20 a week ago, Chin-Hong said.
In the Bay Area, three counties are urging more people to consider wearing masks in indoor public spaces as the coronavirus surges. The Contra Costa County Public Health Department “recommends the wearing of masks in crowded indoor settings, especially among those who are at high risk for severe illness from infection,” the agency said Tuesday, following similar requests from health officials in San Francisco and Marin County. “.
The recommendation to wear a mask, compared to advice such as washing hands and staying away from sick people, is likely to be met with backlash from some.
“As soon as people see this, like in their minds, it sets off a chain reaction of all the negative effects of the pandemic, having to shut down and social isolate,” said infectious disease expert Abrar Karan. said the doctor.
But masks do help reduce the risk of infection, and people don’t have to wear them all the time to benefit. Karan said he socialized and ate at indoor restaurants. But he would decide to wear a mask in other situations, such as “when I travel” and, of course, at work.
Doctors say wearing a mask is one of many tools people can use to reduce their risk, and is especially helpful in crowded indoor settings.
Callan said he’s seeing more coronavirus-positive patients during his urgent care shifts, and he recommends more health care providers take the time to order tests. He said he worries that when people have relatively mild symptoms, they may be sent home without being tested.
But this could miss potential COVID-19 diagnoses, which could lead to patients being prescribed antiviral drugs like Paxlovid.
Without testing, Callan said, “you run the risk of taking shortcuts and not prescribing people the medication they actually deserve.”
Times staff writer David Wharton contributed to this report from Saint-Denis, France.
