HOUSTON, Texas — A large group of people who had come in contact with Thomas Eric Duncan, the Liberian man who brought Ebola to the U.S., have been cleared of the virus by the Centers for Disease Control and Prevention (CDC). The group of 43 people had been quarantined for 21 days by the City of Dallas and monitored twice daily. Amid the release, however, a new study questions whether the 21-day incubation period is long enough.
The individuals are “able to continue normal daily activities without being monitored for symptoms,” a press release from the Texas Department of State Health Services said. “The group is a mix of health care workers, household contacts and community members whose last possible contact with the state’s first patent was Sept. 28.”
But now, some scientists are questioning whether 21 days is a long enough incubation period.
Charles Haas, an environmental engineering professor at Drexel University and lead researcher of the study, wrote in a recent issue of the PLOS: Outbreak journal, “Twenty-one days has been regarded as the appropriate quarantine period for holding individuals potentially exposed to Ebola Virus to reduce risk of contagion, but there does not appear to be a systemic discussion of the basis for this period.”
According to Haas, statistics gathered from West African countries afflicted by Ebola show that there is up to a 12 percent chance someone may be infected with the virus after the 21-day period.
He wrote, “While the 21-day quarantine value currently used may have arose from reasonable interpretation of early outbreak data, this work suggests a reconsideration is in order, and that 21 days may not be sufficiently protective to public health.”
The World Health Organization additionally states that one in 50 individuals who contract Ebola have an incubation period longer than than 42 days.
In the face of such revelations, the U.S. government does not appear to be questioning whether 21 days is a sufficient time period for exposed individuals to be quarantined.
Texas Department of State Health Services Commissioner David Lakey said, “I’m happy we can tell people they are free and clear of monitoring. It provides a measure of relief and reassurance.” Dallas City Administrator Clay Jenkins reportedly added, “That is very good news. This is a defining moment for Dallas.”
Two nurses, both currently fighting for their lives in isolation, contracted Ebola from Duncan. At this time, no others have been diagnosed with the deadly virus.
Follow Kristin Tate on Twitter @KristinBTate.