Ivermectin Advocates Promote Unproven Treatment Amid Andes Hantavirus Outbreak

Medical experts are warning against the use of unproven treatments following reports of a rare Andes hantavirus outbreak linked to international travelers on an expedition cruise ship. The vessel traveled between Argentina, Antarctica, and South Africa, and health authorities have identified several cases beyond the ship.

The outbreak has triggered a resurgence of claims on social media promoting the antiparasitic drug ivermectin, along with zinc and vitamin D, as methods to prevent or treat the rodent-borne disease. Infectious disease experts state there is no clinical evidence to support the use of ivermectin against hantaviruses.

The Andes hantavirus is primarily found in South America and can cause severe respiratory illness. While most hantaviruses do not spread between humans, the Andes strain is the only one known to demonstrate a limited ability for person-to-person transmission. The virus can be deadly, with mortality rates estimated as high as 50 percent in some outbreaks.

On May 6, 2026, former congresswoman Marjorie Taylor Greene posted on X suggesting that ivermectin, zinc, and vitamin D could prevent the disease. In a separate post, Greene shared a 2024 article regarding mRNA hantavirus vaccine research, claiming that pharmaceutical companies manipulate the virus (bioweapon) and make the vaccine (poison).

Other figures associated with the promotion of ivermectin during the Covid-19 pandemic have also circulated claims. These include commentator Josh Walkos, known as Champagne Joshi, who questioned the development of hantavirus vaccines, and physician and activist Mary Talley Bowden, whose post regarding ivermectin and hantavirus received millions of views on X.

Medical professionals have pushed back against these claims, noting the lack of scientific basis for using ivermectin in this context.

Vincent Racaniello, a professor of microbiology and immunology at Columbia University, stated there is no evidence that the drug works for any hantavirus. He warned that promoting the drug is irresponsible because high doses of ivermectin can be damaging.

Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, confirmed that there is no meaningful clinical evidence for the drug’s efficacy against the virus. Adalja noted that ribavirin is the only antiviral that has been formally evaluated in clinical trials for hantavirus, though those results showed limited benefit.

While ivermectin is FDA-approved for specific human parasitic infections, such as intestinal strongyloidiasis and river blindness, the agency warns that improper use or excessive doses can lead to serious neurological complications and seizures.

The promotion of ivermectin coincides with political efforts in some Republican-led states to increase access to the medication. On May 6, 2026, the South Carolina House passed legislation that would permit ivermectin to be sold without a prescription.

The current public health landscape is further complicated by leadership changes and restructuring within federal agencies. Robert F. Kennedy Jr., who has criticized clinically informed public health policies and defended the off-label use of ivermectin, now oversees the Centers for Disease Control and Prevention (CDC) and the Department of Health and Human Services (HHS).

Recent restructuring at the CDC led to the elimination of all full-time employees within the Vessel Sanitation Program, the unit responsible for investigating outbreaks on cruise ships. Although the administration confirmed the cuts were reversed following the hantavirus outbreak, the chief of the Vessel Sanitation Program announced his retirement on May 6, 2026.

President Donald Trump, who previously promoted hydroxychloroquine during the Covid-19 pandemic, offered limited comment on the current outbreak. When asked about the virus on May 7, 2026, he told reporters it should be fine.

Health communication experts suggest that enduring skepticism toward public health institutions is driving the spread of these unsupported claims. Rebecca Fish, a health communications professor at the University of North Carolina Hussman School of Journalism and Media, noted that public trust was damaged by evolving recommendations during the Covid-19 pandemic, such as the acknowledgment by former NIAID Director Anthony Fauci that the 6-foot social distancing rule lacked firm data.

Fish explained that when people feel ridiculed for asking questions, they often seek information outside of official authorities, creating a vacuum that can be filled by misinformation.

Experts emphasize that while public distrust is a factor, it does not replace the necessity for clinical evidence. Adalja stated that clinical claims must be supported by real evidence rather than anecdotal reports.

The Department of Health and Human Services and the CDC did not respond to inquiries regarding whether they have evaluated ivermectin for the Andes hantavirus or if they plan to address the unsupported treatment claims currently circulating online.