At a news conference in Omaha on Monday morning, federal and Nebraska officials corrected the HHS statement, saying the United States has repatriated 18, not 17, people, including 17 U.S. citizens and one person with dual British-U.S. citizenship. Passenger ages range from late 20s to late 70s and early 80s.
On the flight to Omaha, two were transferred to special biocontainment units “out of extreme caution.” That includes the person who tested “mildly positive” and a second person who developed symptoms. For now, the definition of symptoms is “liberal,” including anything as mild as nasal congestion, officials said at the news conference.
Three people in biocontainment in the US
Of the 18 people, 15 (including the dual national) are asymptomatic and are in the quarantine unit.
The person with the “mild positive” test is housed in Nebraska’s biocontainment unit. That person is said to be asymptomatic for now. At the press conference, officials offered only vague answers about what they meant by “mildly positive.” But they are probably referring to the cycle threshold (Ct value) for the real-time PCR test used to detect fragments of hantavirus genetic material to confirm an infection. The test runs repeated cycles to try to amplify specific fragments of genetic material that may be present. A test is generally considered negative if there is no clear signal after 40 cycles. But it is not a precise limit, and weak signals that appear after 35 or more cycles can be considered ambiguous: possibly an early or late infection when there is little genetic material from the virus present, or possibly simply contamination.
The two remaining passengers are a couple traveling together, one of whom is the person previously identified as having symptoms. They were moved together to a biocontainment unit at Emory University in Atlanta. The reason for the move is to ensure that the biocontainment unit in Nebraska, which has a small capacity to isolate hantavirus cases, can reserve space in case any of the 15 in quarantine develop an infection, officials explained at the press conference.
