Hantavirus – Population Vulnerability, Transmissability, & Virulence

Posted on | May 12, 2026 | 2 Comments

Note: There was a prior outbreak of the Andes variant Hantavirus reported in the New England Journal of Medicine 6 years ago.

Mike Magee

In 1948, General George Marshall, reflecting on the success of the World War II vaccine program, famously stated “We now have the means to eradicate infectious disease.” A frequent but untrue urban legend attributed incorrectly to U.S. Surgeon General William H. Stewart  nearly two decades later was that it was time to “close the book on infectious diseases.” 

The “end of scientific hubris” would be quietly declared twenty-two years later, on June 5, 1981, on page two of the CDC’s MMWR publication with the headline “Pneumocystis Pneumonia – Los Angeles.” Wrestled to the ground, but still with no definitive cure for HIV/AIDS, Covid-19 would arrive on our shores in 2019 and ultimately claim 1.3 million American lives (and 7.1 million worldwide), and it could have been much worse had mRNA vaccines not arrived in the nick of time.

The Institute of Medicine in 1992 took a broad view of the worldwide threat with its publication of “Emerging and Reemerging Infections.” Minnesota Epidemiologist Dr. Michael Osterholm caught the spirit of that publication in his testimony to Congress on May 31, 1996 when he stated, “ I am here to bring you the sobering and unfortunate news that our ability to detect and monitor infectious disease threats to health in this country is in serious jeopardy.” 

That same year, Nobel Laureate Joshua Lederberg MD, in a JAMA editorial wrote, “Our fight with microbes is far from over …odds are tipped in their favor…they outnumber us a billion fold, and mutate a billion times more quickly…pitted against microbial genes, we humans mainly have out wits.”

That’s not very encouraging when you consider the fact that our current President, on April 23, 2020, mused in an official coronavirus televised briefing, that somehow internalizing disinfecting bleach might resolve the infection. Now six years later, he has single-handedly dismantled the scientific research and public health leadership of our nation, and left the top post in the hands of our most notorious vaccine denier, RFK Jr.

So here we are, at the front end of a now familiar story. There’s an outbreak in a distant site. Some people have died, rather suddenly. Evacuations and surveillance have occurred. Information released is contradictory and confusing. The President (thankfully) is distracted for the moment by plans for a Ballroom and Reflecting Pool. And alarms are just beginning to be sounded.

What do we know about Hantavirus, or more specifically about the Andes variant of Hantavirus?

Let’s set the stage. There are three measures that matter when it comes to assessing epidemic risk from a microorganism – 1) Population Vulnerability, 2) Transmissibility of the organism, 3) Virulence. Consider the current Measles epidemic in the U.S. Formerly largely eradicated, RFK Jr. and his allies have managed to ignite a modern day epidemic by encouraging families to avoid accessing the highly effective measles vaccine. In so doing, they have created pockets of citizens who have never been exposed to either the active organism or elements of it in the constructed and harmless vaccine. These pockets are not immune to the infectious agent, and without herd immunity, are highly vulnerable.

Secondly, it turns out Measles is one of the most transmissible pathogens that exists. On average, one infected individual within an unprotected human population, will spread the disease to 16 others. Finally, and mercifully, Measles causes a great deal of morbidity, but relatively little mortality. It is fatal in roughly 1.3% of those who are infected.

Now for comparison, let’s consider the Andes version of Hantavirus (ANDV Hantavirus). First, it bears repeating, while there are many versions of the Hantavirus, largely spread by contact with rodent feces and historically not a huge threat to humans, that is absolutely not the case with the Andes version. Through mutations, it has acquired the capacity to spread by aerosolization from one infected human to another. 

As for vulnerable populations, except in small geographic centers such as the Andes region of Argentina, the vast majorities of humankind has never been exposed to the Andes version of Hantavirus. This suggests massive potential population vulnerability. There is no vaccine currently, but scientists are already at work developing one.

As for transmissibility, historically infected individuals in the past on average passed the organism on to two others. But this likely does not apply to the Andes mutant. In the recent cruise outbreak, among 150 voyagers, 11 are known to have contracted the disease, and 3 died (27%).

Finally, when it comes to virulence, the Andes Hantavirus is quite deadly. Since surveillance began in the U.S. in 1993, there have been 890 cases, mostly in the southwest and mainly involving a different variant, the Sin Nombre Hantavirus. The fatality rate for this group was 35%. European outbreaks with less virulent variants have had fatality rates below 15%.

Where are we now? We do not know for certain. The virus can take six, and even eight weeks, to become symptomatic. The W.H.O. has taken the lead in surveillance and follow-up. The MV Hondius carried 140 passengers and crew, now dispersed across the globe. Two days ago a French woman was hospitalized at Bichat Hospital in Paris, and became the 11th traveler diagnosed with the illness. The W.H.O. says more cases are to be expected. The 32 ship crew members remain quarantined on the ship until it docks in the Netherlands. 18 Americans remain under surveillance at a secure medical facility with 16 in Omaha, Nebraska and 2 in  Atlanta, Georgia. One has tested positive with mild symptoms.

Eight years ago, in 2018, there was an outbreak of the Andes variant hantavirus in the village of Epuyen, Argentina. The official report read, “On November 3, 2018, the man attended a birthday party for 90 minutes along with around 100 other people in the village in Argentina’s Chubut Province, near the Chilean border.” 34 were infected and 11 died (32%). The fact that the deaths happened rapidly paradoxically limited the infection’s wider spread. Of the 80 health care workers who managed these illnesses, none contracted the disease.

A thorough epidemiologic investigation of that event was published two years later in the New England Journal of Medicine. Here were their summary observations at the time.

1. “The super-spreading capability of the ANDV Epuyén/18−19 strain shows a facility for sustaining continuous chains of transmission if no control measures are enforced.”
2. “The person-to-person transmission calls for a careful evaluation of the epidemic potential and a biologic risk assessment of ANDV strains and viruses.”
3. “The absence of evidence for ANDV adaptation within or between hosts or for differences in viral diversity between spreaders and nonspreaders indicates that permissive ecology and social factors have a more substantial influence than genetic changes in sustaining person-to-person transmission in human hosts.”
4. (Compared to a strain 22 years earlier) “few genomic mutations were identified among the strains involved in the outbreak that were transmitted from person to person.”

Appreciating our prior performance with Covid, the life saving and timely appearance of mRNA vaccines, and two person to person super-spreader outbreaks in 8 years, our researchers need to have their eyes on the ball. Specifically they should:

1. Compare the current ANDV hantavirus genome to the 2018 and 1996 variations and publish the genomes and their variants.
2. Create an mRNA vaccine for the 2026 ANDV hantavirus.
3. Institute mandatory screening for 2026 ANDV hantavirus for all patients admitted to U.S. hospitals with acute severe respiratory infections. 

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