Westerdam Passengers at Low Risk of Coronavirus Infection, C.D.C. Says

Westerdam Passengers at Low Risk of Coronavirus Infection, C.D.C. Says

Passengers aboard the cruise ship Westerdam who have returned to the United States no longer need to isolate themselves and can resume normal activities, despite the fact that one passenger tested positive for the new coronavirus in Malaysia, the Centers for Disease Control and Prevention has advised.

A spokesman for the agency said on Saturday that the passenger’s diagnosis, confirmed twice by health officials in Malaysia, was a false-positive and noted that no other infections among passengers aboard the ship had been reported.

But on Sunday, the agency said that it had no direct evidence that the test result was a false-positive. Malaysian health officials announced that the passenger, an 83-year-old American woman, now tests negative for the infection, but experts say that is to be expected in a patient recovering from the illness.

(The test looks for an active infection; it is not an antibody test, which can tell whether a patient has ever been infected.)

“I’m thinking they must have some information from the testing laboratory in Malaysia that would give the C.D.C. confidence in saying yes, that was a false-positive result,” said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University.

“Obviously, if it was a true positive, you would keep all those people in self-monitoring.”

The C.D.C. had issued that advice to state and local health departments last week, telling Westerdam passengers that they should restrict public activities for 14 days because they might have been exposed to the virus.

The owner of the ship, Holland America Lines, a division of Carnival Cruise Lines, celebrated the loosening of restrictions on Westerdam passengers.

“While we were not surprised by these results, we were very pleased to receive this confirmation,” Holland America said in a letter to Westerdam passengers. “C.D.C. does not recommend isolation or quarantine for guests returning home from Westerdam.”

On Sunday, the C.D.C. also said that Westerdam passengers would not require testing for the coronavirus. Tests of nearly 1,500 passengers, mostly conducted by Cambodian health officials, had turned up no other infections, the agency said, and therefore the passengers are at little to no risk of carrying the virus.

The Coronavirus Outbreak

  • What do you need to know? Start here.

    Updated Feb. 10, 2020

    • What is a Coronavirus?
      It is a novel virus named for the crown-like spikes that protrude from its surface. The coronavirus can infect both animals and people, and can cause a range of respiratory illnesses from the common cold to more dangerous conditions like Severe Acute Respiratory Syndrome, or SARS.
    • How contagious is the virus?
      According to preliminary research, it seems moderately infectious, similar to SARS, and is possibly transmitted through the air. Scientists have estimated that each infected person could spread it to somewhere between 1.5 and 3.5 people without effective containment measures.
    • How worried should I be?
      While the virus is a serious public health concern, the risk to most people outside China remains very low, and seasonal flu is a more immediate threat.
    • Who is working to contain the virus?
      World Health Organization officials have praised China’s aggressive response to the virus by closing transportation, schools and markets. This week, a team of experts from the W.H.O. arrived in Beijing to offer assistance.
    • What if I’m traveling?
      The United States and Australia are temporarily denying entry to noncitizens who recently traveled to China and several airlines have canceled flights.
    • How do I keep myself and others safe?
      Washing your hands frequently is the most important thing you can do, along with staying at home when you’re sick.