A wave of the highly contagious respiratory syncytial virus is sweeping across the United States — sending greater numbers of babies and toddlers to the hospital, recent data show.

The onset of RSV comes as the country heads into the wider fall-and-winter respiratory virus season, also typically marked by increased circulation of ailments such as COVID-19 and the flu. But RSV, the leading cause of infant hospitalization nationwide, presents particular risk for the youngest babies, a major reason health experts recommend pregnant women either get vaccinated near their delivery date or immunize their newborns.

“This is the perfect time to get your vaccine for RSV if you have never gotten one,” the Los Angeles County Department of Public Health said in a statement to The Times.

RSV can spread through coughs or sneezes but also by touching a contaminated surface, such as a door handle, and then touching your face before washing your hands, health officials warn.

For the week ending Oct. 11, about 1.2% of emergency room visits nationwide among infants younger than 1 were due to RSV — up from 0.4% a month earlier, according to data posted by PopHIVE, a project led by the Yale School of Public Health.

“An RSV wave is starting to take hold,” epidemiologists Katelyn Jetelina and Hannah Totte wrote in the blog Your Local Epidemiologist.

RSV can be dangerous for infants, older adults and people with certain medical conditions, according to the U.S. Centers for Disease Control and Prevention. RSV can cause pneumonia, as well as a severe inflammation of the lungs’ small airways, known as bronchiolitis, the California Department of Public Health said.

“The issue with kids is that their airways are so small that when it causes inflammation in the airways, it’s just very hard to breathe,” said Dr. Peter Chin-Hong, a UC San Francisco infectious diseases expert. “So they come in with wheezing … and that’s why they get into trouble.”

Nationally, RSV kills up to 300 children under age 5 annually, and can send up to 80,000 to the hospital. Among seniors age 65 and older, the virus can cause up to 10,000 deaths in a typical year and as many as 160,000 hospitalizations, according to the CDC.

“I think it’s been kind of invisible, mainly because until recently … people wouldn’t test — we couldn’t test for RSV until the age of molecular diagnostics,” Chin-Hong said. “So it has been kind of an invisible epidemic.”

RSV is “kind of a bronze medalist of respiratory viruses, with COVID and influenza No. 1 and No. 2, duking it out, and RSV is No. 3 for older adults,” he added. In general, RSV is the first to emerge during the fall-and-winter virus season, followed by flu then COVID, Chin-Hong said.

Before immunizations became available, about 2% to 3% of young infants were hospitalized for RSV annually, according to the CDC. Most children who are hospitalized for acute respiratory disease caused by RSV were previously healthy, according to a study published by the journal Pediatrics.

They may require oxygen or intravenous fluid or even be put on a ventilator to help them breathe, according to the CDC.

Unlike the flu and COVID-19, there are no antiviral drugs to treat RSV once infection sets in.

For now, the combined activity of respiratory illness from RSV, flu and COVID-19 is considered “very low” in California, state health officials said.

But “we are starting to see the beginnings of respiratory virus season,” the L.A. County Department of Public Health said.

Health officials in Santa Clara County, Northern California’s most populous, are already reporting “medium” levels of RSV in the wastewater of San José, Palo Alto and Sunnyvale.

Now is exactly the time to get vaccinated if you haven’t already — “especially before respiratory virus activity potentially increases later,” said Dr. Regina Chinsio-Kwong, the Orange County health officer.

RSV immunizations are recommended for pregnant women between 32 and 36 weeks of gestational age — about one to two months before their estimated delivery date — as well as for everyone age 75 and up and those age 50 to 74 with underlying medical conditions such as diabetes, cancer, kidney disease, weakened immune systems, asthma or heart disease. Vaccines are also recommended for individuals who live in a nursing home or long-term-care facility.

If a pregnant woman wasn’t vaccinated against RSV, officials recommend her infant get immunized.

RSV vaccinations are fairly new, being introduced in 2023. There are now three brands — Pfizer’s Abrysvo and GSK’s Arexvy were licensed in May 2023, and Moderna’s mResvia in June 2024. All three can be used for older adults, but only the Pfizer vaccine is available for pregnant women.

Infants were also able to get immunized starting that year through monoclonal antibodies, which aren’t technically vaccines but function similarly in this case.

Older adults who already received an RSV vaccination generally don’t need to get another one.

The arrival of those vaccines followed a particularly brutal 2022-23 respiratory virus season when California was slammed by a hospital-straining “tripledemic” of RSV, flu and COVID.

Unlike the RSV shots, flu and COVID vaccinations are generally recommended ahead of every fall-and-winter virus respiratory season. Older adults, those age 65 and up, can get the COVID vaccination every six months, according to the California Department of Public Health.

People can get the RSV, flu and COVID vaccinations all during the same visit to a healthcare provider, Chinsio-Kwong said.

“Receiving all eligible vaccines at once is considered best practice, as it helps avoid missed opportunities due to scheduling challenges,” she said.

Studies have shown the RSV immunizations are effective.

During last year’s respiratory virus season, there were significant reductions in the RSV hospitalization rate for babies, data show. Data also show RSV vaccines were effective in preventing symptomatic illness in older adults.

Chin-Hong said he suggests “everyone should get it” if they are 75 or older, and for those between age 50 and 74 with heart or lung disease or are very immune compromised, “I think the juice is worth the squeeze.”

Annual routine flu vaccines are recommended for everyone who is at least 6 months old.

As for COVID, a vaccine can be given to anyone who wants one. The California Department of Public Health specifically recommends the shots for everyone age 65 and up, babies age 6 months to 23 months, children and teenagers who have never been vaccinated, and people with certain health risk factors and those in close contact with them.

The California Department of Public Health also recommends pregnant women get the COVID vaccination.

After concerns earlier this season about how difficult it might be to get COVID vaccinations, pharmacists and California health officials now say securing the shots is relatively easy.

The controversy arose in the late summer amid confusing guidance coming from agencies overseen by Health and Human Services Secretary Robert F. Kennedy Jr., who has disparaged vaccinations.

There was a period during which the Food and Drug Administration had belatedly approved COVID-19 vaccines only for those age 65 and up and younger people with underlying health conditions. An unprecedented delay in the CDC issuing its own recommendations had the effect of snarling vaccinations for many.

In some states, that meant people were being turned away from getting the COVID vaccine at their local pharmacy, including seniors, even as a late summer surge was raging. And at one point, the powerful CDC Advisory Committee on Immunization Practices nearly recommended the COVID vaccine be available by prescription only.

On Oct. 6, acting CDC Director Jim O’Neill officially lifted the agency’s recommendation that adults under age 65 get the updated COVID-19 vaccine, saying instead that doing so should be based on “individual-based decision-making” in consultation with health professionals.

Now, “patients can go into the pharmacy” and can have conversations on whether to get the COVID-19 vaccine with a professional, Allison Hill, a director of professional affairs for the American Pharmacists Assn., said during a recent webinar.

California also recently clarified state law to make sure that pharmacists can independently administer the COVID vaccine, according to Dr. Erica Pan, director of the state Department of Public Health.

A controversial plan to kill one owl species to save another cleared a major hurdle.

The full Senate on Wednesday struck down a GOP effort to prevent the cull of up to 450,000 barred owls in the Pacific Northwest over three decades, ending a saga that created strange political bedfellows.

It’s a major win for environmentalists and federal wildlife officials who want to protect northern spotted owls that have been crowded out by their larger, more aggressive cousins. In recent weeks they got an unlikely ally in loggers who said scuttling the U.S. Fish and Wildlife Service plan could hinder timber sales.

But it’s a blow to an equally unusual alliance that includes right-wing politicians and animal rights advocates who argue the cull is too expensive and inhumane. The Trump administration leaned on Republican lawmakers to get out of the way, scrambling partisan lines.

Sen. John Kennedy, a conservative from Louisiana, sought to nix the owl-killing plan via the Congressional Review Act, which can be used to overturn recent rules by federal agencies.

Kennedy said Interior Secretary Doug Burgum, whose portfolio includes timber production, recently called him and told him to abandon the resolution. This month logging advocates said that stopping the cull would jeopardize timber production goals set by the Trump administration.

But Kennedy was not persuaded.

“The secretary needed to call somebody who cared what he thought, because I think he’s wrong,” Kennedy said on the Senate floor. “I think he and the other members of the administrative state at the Department of the Interior decided to play God.”

Flanked by pictures of owls and bumbling cartoon hunter Elmer Fudd, Kennedy praised barred owls for their “soulful eyes” and “incredibly soft” feathers. But he acknowledged they’re better hunters than spotted owls. Barred owls, which moved over from eastern North America, are outcompeting spotted owls for food and shelter in their native territory.

Ultimately the resolution failed 72 to 25, with three lawmakers not voting. Nearly all those who voted in favor of the resolution were Republican, but even more Republicans voted against it. The Fish and Wildlife Service approved the barred owl cull last year under the Biden Administration.

“I feel a lot of relief because this was one of the most major threats to the long-term, continued existence of the northern spotted owl in many years,” said Tom Wheeler, executive director of the Environmental Protection Information Center. “We’ve passed this hurdle, which isn’t to say there aren’t other hurdles or road bumps up ahead, but this feels good.”

Wheeler described the failed effort as a “nuclear threat” — if the resolution had passed, the Fish and Wildlife Service would have been blocked from pursuing any similar rule, unless explicitly authorized by Congress.

Now Wheeler said he and his allies will continue to push for the owl cull to be carried out, and for federal funding to support it.

Animal welfare advocates like Wayne Pacelle, president of Animal Wellness Action and Center for a Humane Economy, are dismayed.

“What this means is that not only are barred owls at extreme risk of large-scale shooting, but spotted owls and old-growth forests are at risk from chainsaws,” Pacelle said of the failed resolution.

Pacelle’s camp vowed to continue the fight. A lawsuit challenging the hunt they filed against the federal government last fall is moving forward. And they’ll try to ensure money doesn’t flow to the program.

In May, federal officials canceled three related grants in California totaling more than $1.1 million, including one study that would have included lethally removing barred owls from more than 192,000 acres in Mendocino and Sonoma counties.

However, there are other projects to kill barred owls in the Golden State, according to Peter Tira, a spokesperson for the California Department of Fish and Wildlife.

One $4.3-million grant issued by the state agency will support barred owl removal in the northwestern part of the state, along with other research. Another grant issued by NASA to a university involves killing barred owls in California as well as creating a tool to prioritize areas where the raptors need to be managed.

It’s not clear how or if the government shutdown, now stretching into its 31st day, is affecting the projects, Tira said in an email.

Over the last decade, clinics have popped up across Southern California and beyond advertising something called magnetic e-resonance therapy, or MERT, as a therapy for autism.

Developed by the Newport Beach-based company Wave Neuroscience, MERT is based on transcranial magnetic stimulation, a type of brain stimulation that’s approved by the Food and Drug Administration to treat depression, obsessive-compulsive disorder, migraines and smoking addiction.

Clinics licensing MERT have claimed that their trademarked version of the treatment can also produce “miraculous results” in kids with autism, improving their sleep, emotional regulation and communication abilities. A six-week course of MERT sessions typically costs $10,000 or more.

The FDA hasn’t approved MERT for this use. However, prescribing drugs or devices for conditions they aren’t approved for, which is known as off-label prescribing, is a legal and common practice in medicine.

But when such treatments are offered to vulnerable people, a group of researchers argue in a new peer-reviewed editorial in the medical journal Transcranial Magnetic Stimulation, they should be evidence-based, clearly explained to patients and priced in a way that reflects the likelihood that they will work as advertised.

Most clinics advertising off-label TMS as a therapy for autism don’t meet those standards, the researchers say.

Autism is “the biggest off-label business … [and] the one that is the greatest concern,” said Dr. Andrew Leuchter, director of UCLA’s TMS Clinical and Research Service.

Leuchter is one of three researchers with TMS expertise who recently called for the establishment of ethical guidelines around off-label TMS marketing in the field’s primary journal.

Written with Lindsay Oberman, director of the Neurostimulation Research Program at the National Institute of Mental Health, and Dr. Holly Lisanby, founder of the NIMH Noninvasive Neuromodulation Unit and dean of Arizona State University’s School of Medicine and Advanced Medical Engineering, the editorial singles out MERT as an “example of off-label TMS where there is negligible evidence of efficacy.”

“There is extremely limited scientific evidence at present that any form of TMS has efficacy and safety in improving the core symptoms of language, social skills, or behavioral disturbances associated with [Autism Spectrum Disorder],” the editorial states. “Websites and other promotional materials that fail to acknowledge this limited evidence-base can create a risk of bias and potential for false expectations.”

Dr. Erik Won, Wave’s president and chief medical officer, did not respond to requests for comment.

A Times investigation last year found there are no large scientific studies demonstrating that MERT is significantly better than a placebo at improving speech and communication challenges associated with autism. Wave has not conducted any clinical trials on MERT and autism.

Won said last year that Wave is working to obtain funding “for further studies and ultimately an FDA indication.”

Websites for clinics offering MERT often feature written testimonials from parents describing what they saw as positive changes in their children’s moods or spoken-language abilities after treatment sessions.

Without data, however, there is no way to know whether a patient’s anecdotal experience is typical or an outlier, according to Zoe Gross of the Autistic Self Advocacy Network, a nonprofit group run by and for autistic adults.

“Be wary of therapies that are sold to you with testimonials. If you go to a clinic website and they have dozens of quotes from parents saying, ‘This changed my child’s life in XYZ ways,’ that isn’t the same as evidence,” Gross told The Times last year.

A therapy could have only a 1% success rate, she said, and still yield dozens of positive testimonials once thousands of people have tried it.

For families unsure of whether a particular commercial therapy might be valuable for their child, “ask the advice of a clinician or an autism scientist who is not connected to the facility providing a service, just to get a frank appraisal of whether it’s likely to be helpful or likely to be worth the money,” said James McPartland, director of the Yale Center for Brain and Mind Health, who is currently studying the relationship between TMS and social perception in autistic adults. “Before you want to ask someone to spend resources on it, you want to have a certain degree of confidence [that] it’s going to be useful.”