Moderna Collaborates on Preclinical mRNA Hantavirus Vaccine in South Korea

Newsweek reported that claims have circulated on social media that Moderna is developing an mRNA vaccine for hantavirus. The discussion increased after reports of hantavirus cases linked to the Dutch cruise ship MV Hondius. Three passengers from the ship have died and one remains in intensive care in a South African hospital, according to the Associated Press.

Health authorities have confirmed the outbreak involves the Andes hantavirus strain, the World Health Organization said. The company has been involved since 2024 in a preclinical research collaboration based in South Korea. The project centers on hantaviruses that cause hemorrhagic fever with renal syndrome, a form of the illness primarily found in East Asia and parts of Europe.

South Korea reports 300 to 400 such cases each year, often among military personnel and people in rural areas. Hantavirus refers to a family of related viruses with different strains circulating in Asia, Europe and the Americas. Vaccines for one strain may not protect against others.

Researchers have worked on hantavirus vaccines for decades. An infectious disease expert at Stony Brook Medicine in New York told Newsweek that earlier candidates were less effective against some European strains while the current effort is designed to provide broader protection across multiple strains.

The research does not focus on the Sin Nombre virus, the strain most commonly linked to cases in the United States that cause hantavirus pulmonary syndrome. U.S. hantavirus infections remain rare and no approved vaccine is available for use in the country.

The company's role is limited to providing mRNA materials and technical support under its mRNA Access Program. This program assists researchers in other countries exploring vaccines for emerging or neglected infectious diseases. The vaccine candidates remain preclinical and have not entered human trials.

They face significant funding and regulatory requirements before any further development could occur.

Greene wrote on X that the effort involves manipulating a virus and then creating a vaccine for profit. Other conservative commentators made similar statements linking the research to broader vaccine skepticism following the COVID-19 pandemic. One podcast host wrote on X that the company showed foresight by beginning work on a hantavirus vaccine two years ago.

A former U.S. Senate candidate from Utah suggested on X that the cruise ship reports and vaccine development followed a familiar pattern.

Routine and exploratory biomedical research has sometimes been presented since the COVID-19 pandemic as evidence of government overreach. The hantavirus project is a collaboration based in South Korea and is not part of any U.S. vaccination program. The company did not immediately respond to a request for comment.