The first case in the U.S. of a more severe mpox variant has been confirmed in a person who had recently traveled to East Africa and was treated in San Mateo County, the California Department of Public Health announced Saturday.

The person diagnosed with the Clade I variant is isolating at home and recovering, while people who had close contact with the person are being notified by public health officials.

There is no evidence that the strain is spreading in California or the U.S, the California Department of Public Health said. The risk of contracting Clade I mpox in the U.S. remains low, according to the Centers for Disease Control and Prevention.

A less severe variant known as Clade II continues to circulate in the U.S., including in Los Angeles and San Francisco — two of the epicenters of the last outbreak in 2022.

In Africa, a Clade I outbreak has been centered in the Democratic Republic of Congo, which had 6,169 confirmed cases and 25 deaths as of Oct. 6, according to the World Health Organization.

Two years ago, cases of Clade II mpox were rapidly increasing in cities across the globe, particularly in the U.S. While that strain of mpox was rarely deadly, officials declared a worldwide public health emergency in July 2022. In the months that followed, the spread of the virus steadily fell, though cases have never completely gone away.

In August 2024, the appearance of the more deadly Clade I variant once again prompted a global health alert.

Recent evidence, however, suggests that this Clade I outbreak may be causing less severe illness than previous ones, especially when patients get quality medical care, the CDC said. In the past, the strain resulted in death rates of 3% to 11%, but the death rate for this outbreak appears to be closer to 1% with good medical care.

Mpox belongs to the same family of viruses as smallpox but causes milder symptoms such as fever, chills and body aches.

The symptoms for both types of mpox are similar, with more severe cases causing a rash on the hands, feet, chest, face, mouth or genitals. Both strains are transmitted by skin-to-skin or sexual contact.

The CDC recommends that at-risk people, such as men who have sex with men, take precautions, which include getting vaccinated, avoiding skin-to-skin contact with those who have a rash or sores that look like mpox, and washing their hands often.

The Los Angeles County Department of Public Health continues to recommend mpox vaccinations for some people, including men who have sex with men or transgender persons, those living with HIV and those who have had skin-to-skin or intimate contact with someone with suspected or confirmed mpox.

With President-elect Donald Trump’s selection of Robert F. Kennedy Jr. as his nominee to lead the Department of Health and Human Services, numerous public health leaders are voicing fears that the nation’s premier health agencies will be weakened at a time when the country faces rising threats from infectious diseases, emboldened industry lobbyists and the dangerous consequences of medical misinformation.

If confirmed as secretary of HHS, Kennedy — a proponent of fringe medical conspiracies and a self-described “poster child for the anti-vax movement” — would have oversight of institutions including the Centers for Disease Control and Prevention, the Food and Drug Administration, the Centers for Medicare & Medicaid Services and the National Institutes of Health.

Like the two most recently confirmed HHS secretaries, Xavier Becerra and Alex Azar, Kennedy is an attorney with no formal scientific or medical credentials. His purview would include programs and departments he has fiercely criticized in the past, often in ways that opponents say distort or ignore facts and misinterpret science.

Many of the problems Kennedy has publicly said he wants to tackle are concerns shared broadly by healthcare providers, public health officials and members of the public. They include pervasive chronic disease, poor nutrition and the ubiquity of processed foods containing artificial chemicals.

But his nomination has alarmed many public health and medical officials who say they are worried that the solutions Kennedy might deem appropriate could undermine Americans’ health in the long run.

“Putting somebody in charge who is unable to discern the difference between good and bad science is really dangerous for the American people,” said Dr. Peter Lurie, president and executive director of the Center for Science in the Public Interest.

“Yes, there are some things that he supports that we would agree with, but they feel more like the stopped clock that’s right twice a day,” Lurie said, citing food additives as one example. “There are opportunities for small victories. … But overall, it’s dissolved in so many bad ideas that it’s absolutely not worth it.”

Kennedy declined to discuss his plans for HHS with The Times, but he has indicated some priorities for the agency in previous public statements.

For instance, he said Trump would advise against water fluoridation on his first day in office. He told NBC News he wouldn’t “take away” vaccines, but he would “make sure scientific safety studies and efficacy are out there, and people can make individual assessments about whether that product is going to be good for them.”

More than half a dozen experts who spoke with The Times said Kennedy’s suggestions that the science around vaccines is unsound would undercut public health.

The United States has “the best vaccine safety system in the world,” said said Dr. Richard Besser, a former acting CDC director who now leads the Robert Wood Johnson Foundation. “RFK Jr. has done a lot to undermine confidence in that.”

Indeed, cases of measles have been rising in the U.S. as childhood vaccinations lag, especially since the COVID-19 pandemic. The CDC has identified 277 measles cases this year, up from 59 in 2023.

“I don’t want to have to see us go backwards in order to remind ourselves that vaccines work,” Dr. Mandy Cohen, the CDC’s director, said this week at the Milken Institute Future of Health Summit in Washington, D.C.

Kennedy’s zeal to remove fluoride from drinking water on the claim that the mineral causes neurodevelopmental disorders and other health conditions is another example of shirking the best science, said Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health.

“That has been looked at carefully and there has not been evidence of a link,” Willett said. “On the other hand, there are serious problems with lead in water systems.”

Vaccines and fluoride are just two areas where Kennedy will have an opportunity to implement ideas that lack strong scientific support.

Last month, he decried the FDA’s “aggressive suppression” of unproven health remedies like dietary supplements and ivermectin and warned: “If you work for the FDA and are part of this corrupt system, I have two messages for you: 1. Preserve your records, and 2. Pack your bags.”

But food safety advocates who have shared many of Kennedy’s criticisms about lax regulation said gutting the agency is not the answer. Any effort to reduce or eliminate chemical additives in foods would require experienced staffers to draft new rules and shepherd them through the required regulatory process, said Ken Cook, president of the Environmental Working Group.

“If you’ve gotten rid of all the bureaucrats, who’s going to write the regulation?” Cook said.

Or consider FDA’s reliance on user fees from companies that want the agency to approve its medical products. Such fees make up nearly half of the agency’s operating budget. Kennedy and others have criticized such fees, but if those dollars went away, Congress would be unlikely to backfill them, Lurie said.

“Ending user fees is tantamount to starving the agency,” he said. “That would mean a food program that’s limited in what it can do, drugs coming to market more slowly, and vaccines that are even less well-monitored for safety.”

Lurie said he wouldn’t be surprised to see Kennedy task researchers at the National Institutes of Health with looking for damaging side effects of vaccines and elusive benefits of potential therapies that have already been shown to be ineffective, such as chelation as a treatment for autism and ivermectin and hydroxychloroquine for COVID-19.

“He seems to think these hold great promise,” Lurie said. “Most of those ideas are sinkholes for government spending, which is ironic given the Trump administration’s purported devotion to efficiency.”

Significant as the HHS role is, Kennedy would still find his powers curtailed by the limits of the agency’s reach — and potentially by the whims of his boss.

Willett said he agrees with Kennedy that the nation’s health is in decline, and that our food and healthcare systems are “in many ways dysfunctional.” He would welcome efforts to crack down on the amount of salt allowed in foods and to curtail consumption of added sugars, refined grains and sugar-sweetened beverages.

But if Kennedy takes steps like these, “we know for sure he will run into resistance from industry,” Willett said. “It would be interesting to see if he’s prepared to take on Coca-Cola.”

Although Kennedy is passionate about reducing pesticides and other chemicals in foods, it’s up to the Department of Agriculture to regulate pesticide use on crops, and it’s the job of the Environmental Protection Agency to determine what exposure levels are considered safe for people, Cook said. Nor would Kennedy have the power to reform farm subsidies to encourage organic and regenerative agriculture.

“He doesn’t have much purchase on pesticides from his perch,” Cook said. “That’s not really an HHS thing or an FDA thing.”

The FDA does have the authority to regulate the chemicals that come off of food packaging and can find their way into food, and Kennedy could prioritize that, Cook said.

It’s also possible that Kennedy could protect the budgets of the National Institute of Environmental Health Sciences and the Agency for Toxic Substances and Disease Registry, Cook said.

To help him achieve his goals, Kennedy has invited the public to weigh in on people who could fill important roles within the federal government’s health agencies.

Names that have garnered thousands of votes in the “America’s Health” category of his “Nominees for the People” website include Dr. Sherri Tenpenny, who claimed COVID-19 vaccines made people magnetic, and Dr. Simone Gold, the anti-vaccine Beverly Hills physician whose medical license was suspended after she pleaded guilty to unlawfully entering the U.S. Capitol on Jan. 6, 2021. (Her license has since been restored.)

Kennedy’s own accession to the HHS secretary post is not yet certain. Cabinet positions are supposed to be confirmed by the Senate, though Trump has suggested that he may use recess appointments to bypass the need for lawmakers’ approval.

Dr. Georges Benjamin, executive director of the American Public Health Assn., said that even if Kennedy wins confirmation, it’s uncertain how long he would remain in Trump’s good graces.

“I remind folks that his first health secretary didn’t last a year,” Benjamin said. “We’ll see what happens here.”

As H5N1 bird flu spreads among California dairy herds and southward-migrating birds, health officials announced Friday that six more human cases of infection: five in California and one in Oregon — the state’s first.

A seventh presumptive California case is awaiting confirmation from the U.S. Centers for Disease Control and Prevention.

All of the reported cases have been described as mild, and each person is believed to have contracted the illness from infected livestock or poultry. In California, the infections occurred among dairy workers. In Oregon, the patient was a poultry worker.

California’s state epidemiologist, Erica Pan, said that while the announcement of five cases today may sound like a sudden explosion or acceleration in cases, it was an artifact of state reporting deadlines. Three cases had been confirmed by the CDC on Wednesday after California’s reporting deadline. The other two were confirmed Thursday — a day that California does not make reports on case counts.

And there was also a holiday on Monday, which further slowed reporting.

“I would still call these sporadic animals or human infections, and there’s still no evidence of any human to human,” transmission, she said. “These are all workers who are at risk of exposure based on their their work exposures.”

In the Oregon case, the person contracted the disease from a previously reported infected commercial poultry operation outbreak in Clackamas County. A statement from the Oregon Health Authority said there is “no evidence of person-to-person transmission and the risk to the public is low.”

The agency said the person is fully recovered and was treated with oseltamivir, an antiviral medication. The health agency also prescribed the antiviral medication to people who lived in the same home as the patient.

Since March, the U.S. Centers for Disease Control and Prevention has said that 52 people have been infected by the H5N1 virus. Dairy cattle were the source for 30 of those cases, poultry for 21. The source of one more case in Missouri remains unknown.

In addition, a teenager in British Columbia was infected by an unknown source and as of Friday was hospitalized in critical condition.

Twenty-six cases have been identified in California, including the five most recent. All had been in contact with infected dairy cows.

WastewaterScan — an infectious disease monitoring network led by researchers from Stanford University and Emory University, with laboratory support from Verily, Alphabet Inc.’s life sciences organization — follows 28 wastewater sites in California. All but seven have detectable amounts of H5. It is unclear what the source is in each system, but experts say it could be from unpasteurized milk, wild bird droppings or discarded contaminated animal products.

Cities and municipalities that have detected the virus since the beginning of November are: Gilroy, Indio, Lompoc, Los Angeles County, Los Angeles, Marina, Merced, Napa, San Francisco, Ontario, Palo Alto, Redwood City, Riverside, Sacramento, San Diego, San José, Santa Cruz, Southeast San Francisco, Sunnyvale, Turlock and Vallejo.