Women's Health May 13, 2026 0 Comments

Hantavirus vs. COVID-19: The Deadly Differences and Shocking Similarities You Can’t Afford to Ignore!

Ever find yourself scrolling through your feed only to be smacked in the face by yet another hantavirus headline? Yep, same here. Just as we were catching our breath from the whirlwind that was COVID-19, here comes a new viral contender—making waves on a cruise ship no less. It’s enough to make anyone’s heart race, but hold up before you dive into full-on panic mode. The truth? Experts are waving off the doomsday vibes, assuring us that this isn’t the start of another global lockdown. Curious how hantavirus stacks up against the infamous COVID? And why this outbreak, despite its scary name, isn’t sending officials into major red alert? Stick around—let’s unpack the facts, fears, and all the nitty-gritty you need to know about this viral plot twist. LEARN MORE

5 min read

If your social media feed looks anything like mine, hantavirus has completely overtaken it. Given that we’ve only recently moved on from the effects of the COVID-19 pandemic, it’s normal to see headlines about a virus and begin panicking about another global shutdown. But experts say there’s no need for that right now.

For some context, the WHO reported on May 4 that three people died from an outbreak of hantavirus on a cruise ship in the Atlantic Ocean. There are two main kinds of hantavirus: In Europe and Asia, there’s Old World hantavirus, which can result in hemorrhagic fever and kidney complications (also called Hantavirus Hemorrhagic Fever with Renal Syndrome). In the Americas, there’s New World hantavirus, which can cause significant respiratory symptoms called Hantavirus Pulmonary Syndrome.

While both Old World and New World hantaviruses are transmitted through contact with rodents, only the Andes strain (a form of New World hantavirus) has had documented human-to-human transmission. This Andes strain is the same one identified in this cruise ship outbreak.

And though hantavirus and COVID seemed to have appeared out of thin air and spread rapidly, they’re completely different—starting with the fact that COVID was brand new in 2019. “We knew nothing about it at all, and subsequently learned it was quite infectious and transmitted quite readily,” says Thomas Russo, MD, a professor and chief of infectious disease at the University at Buffalo in New York. But Hantavirus Pulmonary Syndrome dates back to 1993, with 890 cases in the United States from then through the end of 2023, per the CDC. A statement from the International Hantavirus Society notes that though cases are low, “rare disease incidence does not imply absent transmission potential.” That said, officials say the outbreak appears to be contained so far, as all of the exposed passengers who just disembarked are being monitored.

Ahead, find out the similarities and differences between hantavirus and COVID and what the experts say about the whole situation.

Meet the experts: Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo in New York; and Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security.

How are hantavirus and COVID transmitted?

While most hantaviruses are spread from rodent droppings, the Andes strain can also be transmitted human-to-human through inhalation of aerosolized viral particles, including respiratory and saliva droplets, Russo explains. It can also be spread through urine and feces. COVID, on the other hand, is spread via respiratory transmission, through coughing, talking, laughing, or sneezing—similarly to how common colds spread.

The rate of transmission is determined through R₀, (pronounced “R naught”) which “stands for reproductive number,” says Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security. “It’s the number of individuals a person infected with a pathogen passes that infection onto.” For instance, the R₀ for tetanus (which is not transmissible human-to-human) would be zero, meaning that a person with tetanus would spread it to zero people.

However, R₀ isn’t an absolute number—it’s a range that depends on specific circumstances surrounding the virus. “Often, it involves the social behaviors and the contact patterns of the person infected,” Adalja explains. So, if someone is a super-spreader or spends more time indoors, they might transmit it to more people, while someone who never leaves their house or spends a lot of time outdoors may spread it to fewer people. So, that number can be misleading sometimes.

It’s hard to estimate the exact R₀ for hantavirus because there haven’t been that many outbreaks. However, one outbreak calculated it at around two, and once infection control measures were put into place, it dropped below one, which “means it’s not transmissible to other individuals,” Russo says.

The exact R₀ of COVID is also hard to pinpoint because there have been so many variants. However, Adalja notes the range was around 2.5 to three, and the omicron variant reached around five—but we also had vaccines around that time, so again, it’s not an exact number.

Still, here’s what we do know about hantavirus: “We think that its transmissibility is not great and could be significantly mitigated—really eliminated—with infection control measures,” says Russo. He also adds that there don’t seem to be any new mutations.

What are the symptoms of hantavirus and COVID?

Both hantavirus and COVID can cause fever, chills, muscle aches and pains, shortness of breath, and coughs “because they both affect the respiratory system in some way [but] they do it in different manners,” Adalja says. As with COVID, the range of severity in symptoms is on a spectrum, and Russo suspects that there will likely be people in this outbreak who exhibit no or minimal symptoms.

How do the mortality rates of hantavirus and COVID stack up?

Experts believe the mortality rate for (New World) hantavirus is around 30 to 40 percent, at least for those who develop cardiopulmonary respiratory syndrome, says Russo. However, these numbers may be an overestimation—the true mortality rate may be a bit lower because asymptomatic people can’t always be identified. COVID’s mortality rate depends on whether you’re vaccinated or not, but it’s generally less than one percent, he adds.

Just like with COVID—and any infectious disease—those with underlying comorbidities (like heart and lung disease), those who might be immunocompromised, or are very young or old, are more likely to have a severe outcome from hantavirus transmission, Russo adds.

How is the CDC handling the hantavirus outbreak compared to COVID?

“There are major concerns about the administration’s ability to deal with any kind of infectious disease emergency,” especially as the CDC is understaffed and many of their top subject matter experts have left, says Adalja. While he notes that the CDC hasn’t released much information about this outbreak to clinicians, he believes they’re handling it well otherwise.

First, the Americans who came off the boat are being isolated and monitored for symptoms. “There is a pretty robust process in place right now at the University of Nebraska and Emory University, which are state-of-the-art facilities to take care of patients like this and to screen passengers,” says Adalja. “And this is not a novel virus.”

It’s also worth noting that there are no secondary cases. “We’ve got a pretty good handle on who’s been exposed and who’s infected and how they’re being appropriately isolated,” says Russo. “The likelihood that this will be a self-limited outbreak that won’t involve a large number of people is very, very high.”

“The ability to develop, for example, a hantavirus vaccine now would be greatly expedited by the availability of mRNA technology.”

Experts believe this outbreak isn’t anywhere near the level of COVID. “I don’t think the hantavirus is going to amount to any threat to the general public,” Adalja says. “Hantavirus is a more forgiving virus than COVID.”

But even if it did become a more widespread virus, the United States is better prepared for any future pandemic thanks to the development of mRNA vaccines. Although scientists had studied mRNA for 30 years, the first mRNA vaccines were developed and authorized for COVID. “That technology in itself is going to enable us to better curtail any future pandemics,” says Russo. “The ability to develop, for example, a hantavirus vaccine now would be greatly expedited by the availability of mRNA technology.”

All in all, experts believe we’re in pretty good shape as long as the virus stays contained.

Addison Aloian is the associate health & fitness editor at Women’s Health, where she writes and edits across the health, weight loss, and fitness verticals. She’s also a certified personal trainer through the National Academy of Sports Medicine (NASM). In her free time, you can find her lifting weights at the gym, running on the West Side Highway in New York City—she recently completed her first marathon, the 2025 New York City Marathon—and watching (and critiquing!) the latest movies that have garnered Oscars buzz. In addition to Women’s Health, she’s made an appearance on the Oprah Podcast and her work has also appeared in Allure, StyleCaster, L’Officiel USA, V Magazine, VMAN, and more.