Acting Centers for Disease Control and Prevention Director Jay Bhattacharya on Sunday downplayed the severity of a hantavirus outbreak that began a cruise ship, comments that came the same day passengers were evacuated from the affected vessel onto Spain’s Canary Islands.

“This is not COVID, Jake,” Bhattacharya told CNN’s Jake Tapper on “State of the Union.” “And we don’t want to treat it like COVID. We don’t want to cause a public panic over this.”

Bhattacharya said the CDC has been in contact with each of the U.S. passengers from the ship and has been coordinating with both domestic and international partners since the outbreak cluster was initially reported to the World Health Organization on May 2.

The 17 Americans on the ship will be sent to a quarantine facility in Nebraska, and the CDC will “interview them and assess them for risk,” according to Bhattacharya.

As international fears about the virus intensified, some leading infectious-disease researchers raised issues about the U.S. response to the outbreak, calling out what they described as a “concerning” lack of coordination between partner agencies.

“A lot of the things you would like to see, we haven’t seen,” Carlos del Rio, the former president of the Infectious Diseases Society of America, told reporters Thursday morning at a briefing hosted by the organization. Del Rio expressed concerns about what he characterized as the CDC’s lack of involvement in directly assisting the WHO, an important partnership that was typical in past international disease outbreaks.

Three people who were aboard the ship MV Hondius have died — a Dutch couple and a German man — after falling ill as the vessel traveled from Argentina to the Canary Islands. A total of eight cases have been confirmed since the initial outbreak on the ship, while a French passenger has also exhibited symptoms since disembarking, according to French Prime Minister Sébastien Lecornu.

None of the other passengers had shown symptoms, Spanish Health Minister Mónica García said at a press conference Sunday.

As many as 38% of people who develop respiratory symptoms after contracting hantavirus may die, according to the CDC’s public resource page on the outbreak. The WHO confirmed that the type of hantavirus responsible for this outbreak is the Andes virus.

“Andes virus is a type of hantavirus spread by rodents in South America and, less commonly, by other infected people,” the CDC reports. It is the only type of hantavirus that is known to spread person-to-person.