The hantavirus outbreak that has killed three people and put 12 countries on alert is less contagious than COVID and likely won’t turn into a major pandemic, a leading hantavirus researcher told The Post.

Officials are scrambling to track and potentially quarantine people who may have been exposed to a rare, human-to-human strain of hantavirus aboard an Atlantic cruise ship, including at least six Americans.

Hantavirus — which normally spreads via mouse droppings and killed Gene Hackman’s wife last year — has a mortality rate as high as 40%, but it’s harder to spread than COVID-19, said epidemiologist Ali Khan.

“It requires large saliva droplets from talking to people, close person-to-person spread. … We’re probably looking at more than a ‘Hello, how are you?’” said Khan, who serves as dean of the College of Public Health at the University of Nebraska Medical Center.

The elderly Dutch couple who likely contracted the virus in Argentina probably had lengthy, close contact with anyone they infected, including the ship’s doctor who treated the husband.

“Maybe prolonged conversations over lunch or dinner. It shouldn’t be casual conversations that started this,” Khan told The Post.

The outbreak occurred on the MV Hondius, which carried around 150 passengers on an Atlantic cruise; it is likely the “Andes strain,” the only form of the virus known to jump from person to person.

Officials across the globe are tracking 23 passengers who returned home from the ship to at least a dozen countries, including the U.S., where two people returned to Texas and one to Virginia.

But normal contact tracing, monitoring, and quarantines for anyone who shows symptoms should be enough to contain the spread.

“Right now they’re asking, ‘Who was on the ship? Who got off? Are they OK?” Khan said.

The situation is closer to last year’s Ebola outbreak in the Democratic Republic of the Congo and Uganda: Cause for alarm, but not mass panic.

“I’ve already got people in my Twitter feed saying, ‘Oh my gosh, you guys are trying to push another MNRA vaccine on us.’ That’s not what’s happening,” Kahn said.

Nevertheless, global health authorities are taking no chances with anyone who may have been exposed to the virus, which flushes fluids into the lungs and slowly suffocates the victim.