A man goes to a birthday party, sits next to someone with hantavirus, catches it, gives it to his wife, and dies. His wife then infects 10 more people at his wake. Another guest at that same birthday party has no interaction with the index patient except to say “hello” as they cross paths, but that person gets sick too.

One index patient, 33 subsequent infections, 11 deaths, four waves of transmission.

This is from a meticulously documented hantavirus outbreak in Argentina in late 2018 and early 2019, published in the New England Journal of Medicine (NEJM). Nearly the exact same Andes strain of hantavirus caused the recent outbreak on the Dutch cruise ship MV Hondius. Yet from the moment this latest outbreak hit the news last month, public-health officials have been claiming that this virus is spread through “prolonged close contact.” The evidence is not nearly so reassuring.

In any outbreak, the single most important question is: How does it spread? The answer informs the guidance for everything else, including how to stay safe, which protective measures to put in place, and who should be notified during contact tracing. Get it wrong and everything else breaks down.

We made this mistake at the start of the coronavirus pandemic, and the cost was high. Health officials thought the virus spread on surfaces (“fomite transmission”) and through large droplets that dissipate quickly and can’t travel six feet. That’s why we spent a full year cleaning elevator buttons and putting stickers on floors telling people where to stand. But these interventions did little to halt the spread of a disease that in fact traveled through small particles that lingered dangerously in poorly ventilated and enclosed spaces.

We’re now getting it wrong again. “This is not a respiratory disease,” Mike Waltz, the U.S. Ambassador to the United Nations, said about the hantavirus in an ABC News interview on Sunday, adding, “It’s very rare to see it transmitted between humans.” Transmission of the virus “requires close contact,” Jay Bhattacharya, the acting director of the Centers for Disease Control and Prevention, insisted last week. The CDC’s official communications have continued to emphasize that “prolonged, close contact” is necessary for transmission, as have other public-health officials outside the Trump administration.

As an expert in what we call “exposure science,” I have spent a career conducting forensic investigations to understand how diseases spread and what we should do about it. As a member of the Lancet COVID-19 Commission, I chaired the Safe Work, Safe School, and Safe Travel task force, and was an early proponent of the theory that COVID spreads through the air. There was evidence early on of airborne transmission, which my colleagues and I tried to draw attention to. We modeled the early-2020 outbreak of the disease on the Diamond Princess cruise ship and found that 90 percent of the spread was through aerosols, not contaminated surfaces, but the CDC didn’t update its guidance until late 2020. I am alarmed to see the same pattern playing out now.

Hantaviruses usually originate in rodent feces. Someone cleans a dusty area that has rodent droppings, inhales the particles, and gets sick. Only the Andes strain of hantavirus is known to be transmitted from human to human. In the outbreak documented in NEJM, the virus spreads without physical contact or prolonged exposure. One patient gets sick after simply crossing paths with someone who was ill. Two others are infected while seated at tables meters away. One person infected five others within 90 minutes at one party. The NEJM authors suggested that the virus spreads through the air.

Although the NEJM evidence is clear, officials have kept repeating “prolonged, close contact,” so I wanted to be sure I wasn’t missing anything. Last week I spoke with a physician who was on the MV Hondius as a passenger but who jumped in to help treat infected passengers after the ship’s official doctor got sick and was evacuated. He told me that the original treating doctor and staff were definitely in close contact with the first patient. But the others who got sick? They had merely shared space in the dining room and the lecture hall, and had not had close contact. We’re now at 10 confirmed cases from the ship, which aligns with the prior outbreak dynamics: one person infecting many, no close contact required.

Every outbreak investigation involves careful clinical workups, painstaking epidemiology, re-created time-activity patterns, and genomic sequencing—but almost every time, without fail, the investigators ignore the actual space where the outbreak took place. Was the cruise ship’s ventilation system working? What filters did it have, and were they running?

This matters because medical teams treating patients need to know how they might be exposed. When infected passengers go home to quarantine, their households need to understand the risk. As passengers fly back to their home countries, contact tracers need to know which exposures matter. The doctor who treated patients on the cruise said on CNN that he relied on goggles, a gown, and hand-washing to protect himself. But given that this virus spreads through the air, an N95 mask and a strong ventilation and filtration system would have served him better.

This outbreak is not likely to spark a pandemic, mostly because the hantavirus is less contagious than influenza, measles, and SARS-CoV-2. But given just how little experience we have with this virus, any certainty is hubris. Thankfully, despite the flawed messaging, the system is broadly working: Officials are investigating, passengers are quarantined, the seriously ill are getting treatment, and the risk to the general public is low. International and national public-health authorities are acting responsibly.

But what happens next depends on how well public-health officials communicate what precautions people should be taking. If people mistakenly believe transmission relies only on “prolonged close contact,” they may take risks they will soon regret.

Public-health officials have to be more honest and more humble about how this virus actually spreads. An essential lesson from COVID is that officials should be candid about communicating that we are often learning in real time, and we should shy away from making bold pronouncements that may prove dangerously misleading weeks or months later. When it comes to preventing an outbreak from becoming a pandemic, insisting on the wrong answer to that most central question—How does it spread?—may well be worse than not having an answer at all.

The now-shuttered U.S. Agency for International Development (USAID) has told Congress it has $19 billion in funds to cover costs associated with closing out the programs it terminated last year, according to a notification sent late last month and obtained by The Hill. 

The notification acknowledges that the price of closing out the agency is likely to cost less than the multibillion-dollar number, but it’s unclear where the leftover funds will go. 

Humanitarian aid experts and Democrats are urging the administration to show some urgency in disbursing it for dire humanitarian needs. 

“If I was an appropriator, I’d be alarmed that the administration is withholding life-saving aid,” Sam Vigersky, international affairs fellow with the Council on Foreign Relations, said. “Between the war with Iran and global funding cuts from the U.S. and others, needs are near record highs. We’re in a moment where every dollar matters.”

USAID was fed “into the woodchipper,” as described by tech billionaire Elon Musk in February 2025. Musk, leading his so-called Department of Government Efficiency, took on the task of shutting down USAID. It locked out staff members and took over the computer systems, terminating the majority of programs in the agency’s roughly $40 billion annual budget. 

Researchers estimated that more than 500,000 children and more than 260,000 adults died as a result of the aid cuts.

On April 20, a notification was sent to Congress from USAID detailing that it planned to use remaining funds to cover costs associated with the closeout of terminated foreign assistance awards. The notification was first reported by Devex.

“Unobligated and/or unliquidated funds that remain after USAID has completed all closeout actions may be used for other foreign assistance programs, such as those currently managed by the Department of State,” the notification reads. 

The “resources available” for closeout funding, the notification said, includes more than $625 million of unobligated funds from 2024 and $3.2 billion in unobligated funds related to global health and economic development programs from 2025. The notification also tallied more than $15 billion in “unliquidated obligations on terminated awards for DOAGs.” 

DOAGs refer to development objective agreements, typically five-year grant agreements between the U.S. and a foreign country.

Closeout costs are listed as “covering final settlements, pending invoices, adjustments to negotiated indirect cost rate agreements, costs associated with disposition of assets and/or other claims.” 

The notification notes that the expected closeout costs are “anticipated to be substantially less than these total amounts.”

One former USAID official, who was granted anonymity to speak candidly, noted the remaining funds were almost half of the State Department’s entire $50 billion foreign assistance budget this year. In 2024, the last year of total data for USAID, the budget was around $35 billion.

“The trend that this speaks to and that Congress should be very concerned about, is that the Trump administration is not spending the money they are appropriating for them,” they said. 

The notification does not include any names of administration officials. Office of Management and Budget Director Russell Vought — whom President Trump has dubbed the “grim reaper” — was assigned as acting USAID administrator last year and tasked with overseeing the agency’s complete shutdown. Reuters reported in February that the White House was using $15 million of USAID funds for Vought’s security. 

Senate Democrats took specific exception with the notification holding back $3.2 billion in development and humanitarian assistance that was appropriated in fiscal 2025. They called it an “unnecessary and illegal impoundment of funds.”

“We write to demand that you reverse this proposal and put the funds to their intended use to save lives and advance U.S. interests as directed by Congress last year,” Sen. Brian Schatz (D-Hawaii) and 16 of his colleagues wrote in a letter sent April 24. 

They note that the $3.2 billion was signed into law by Trump in March 2025 and expires at the end of this September. 

The assistance is earmarked for $300 million for programs to combat HIV/AIDS, $250 million for malaria programs, $320 million for maternal and child health programs, and $650 million for global health security. 

“The Administration should immediately begin using these foreign assistance funds to deliver results for the American people. There is no reason for this FY25 funding to be withheld to cover the wasteful costs this Administration has incurred because it chose to dismantle USAID,” the lawmakers wrote. 

The State Department, Senate Democrats and Republicans with oversight of State Department funds did not return multiple requests for comment from The Hill.

Emily Byers, managing director of global development policy with Save the Children, pointed to a single $69 million program in Niger to illustrate how much impact the remaining funds could stretch. The program was terminated in the USAID shutdown.  

The organization’s maternal and child health program delivered life-saving health and medical services to 1.4 million women and 1.1 million children in Niger, she said. This included immunizations, malnutrition screening and treatment, disease outbreak prevention and treatment, diagnosis and treatment of childhood illnesses and antenatal and obstetric care. 

“Congress has shown continued leadership by appropriating critical funding for maternal and child health and humanitarian response; those investments reflect a bipartisan commitment to saving lives,” she said. “We urge the administration to ensure those resources are swiftly and effectively used to protect children and families in crisis.”

Prescriptions for ivermectin and another antiparasitic drug among cancer patients shot up after actor Mel Gibson discussed an unproven treatment on Joe Rogan's popular podcast, according to a study published today in JAMA Network Open.

Researchers say these findings raise concerns about the potency of celebrity endorsement, which can encourage people with life-threatening illnesses to delay or forgo conventional care that's been confirmed to work in favor of unproven and arguably risky treatments.

Prescriptions increased 2.5 times in cancer patients

The study analyzed electronic medical records from 68,373,949 patients across 67 health systems in the United States in search of prescribing rates of ivermectin and benzimidazole. 

There have been no clinical trials on ivermectin-benzimidazole’s safety and efficacy for treating cancer in people. 

Some cell and animal studies show that the drugs can produce anti-cancer activity. But the dose needed to have even a small effect would typically be considered toxic for humans, said Skyler B. Johnson, MD, of the University of Utah Huntsman Cancer Institute. Johnson wasn’t involved in the study but told CIDRAP News that he worries how ivermectin might affect the way the body processes cancer treatments and other medications.

Despite this lack of proof and possible danger, Gibson claimed on Rogan's podcast in January 2025 that a combination of ivermectin and benzimidazole cured cancer in several of his friends. 

The episode was viewed 60 million times within the first month, and prescribing rates of both medications rocketed. 

Prescribing doubled among all patients from January 1, 2025, to July 31, 2025, compared with January 1, 2024, to July 31, 2024. For cancer patients, rates were even higher, increasing 2.5 times. 

White patients, men, and people living in the South were most likely to have an ivermectin-benzimidazole prescription, according to the study. 

The role of celebrity influencers

Even if people are unharmed by taking these medications, needless prescribing creates excess expense and clogs up an already dysfunctional medical system, explained lead author Michelle Rockwell, PhD, RD, a health services researcher at Virginia Tech.

"Clinicians talk about how difficult it is when the patient demands or asks for a medication that they really feel passionately might help," she said. "And that's where I think these celebrity influencers really play a big role."

Frustrations with the healthcare system, pharmaceutical pricing, and insurance barriers create real grievances that make people easier to exploit, explained Matthew Facciani, PhD, a social scientist at the Yale School of Public Health who wasn't involved in the study.

“We don't know whether patients were taking ivermectin alongside conventional treatment or in place of it," said Facciani. "This is a distinction with very different public health implications."

Ivermectin was also viewed as potential treatment for COVID-19 early in the pandemic, but several clinical trials found it did not lower the risk of severe disease, prevent hospitalization, or speed time to recovery. Misinformation about the drug was linked to a surge in overdose calls to poison control centers in 2021.

Silver linings

The study's authors acknowledge that they tracked only whether a patient received a prescription and not whether they used the drug. Also, some people might have tried to access these medications without a prescription. For example, agricultural retailers sell formulations of ivermectin for livestock. 

And while the prescribing spike occurred after Gibson's appearance on Rogan, the findings don't account for whether other factors drove this activity. Still, the timing suggests that the actor's endorsement had a powerful effect.

If celebrities can convince people to make poor medical decisions, they can potentially do the opposite. Rockwell noted that after Katie Couric had a colonoscopy on TV in 2000, the nationwide rate of colorectal cancer screening increased by 20%.

Also, the demographic patterns revealed in the study "essentially hands public health a map" of where these trusted messengers are most needed, said Facciani. 

"The clinical encounter is likely too late and too brief to be the primary intervention point," said Facciani. "What's needed instead is more public health presence in digital spaces, meeting people where they already are."