Our protection against Ebola in the U.S. depends on guidelines determined by the Centers for Disease Control and Prevention (CDC). But at least one informed researcher wonders if the CDC has allowed a serious breach in its defense strategy.
Right now, the U.S. healthcare system is trying to cope with the first cases of Ebola to strike an American. Supposedly, we are the best-protected people in the world against this type of epidemic. But scientists who are taking a closer look at the ways in which the CDC is trying to minimize the impact of the disease in North America have raised serious concerns about what’s being done.
A study by Charles Haas, an engineering professor at Drexel University in Philadelphia, raises questions about one of the primary defenses against the spread of Ebola: the 21-day isolation period used to quarantine people exposed to the disease.
The World Health Organization reports that in two previous outbreaks of Ebola, people exposed to the illness who did not become sick within 21 days probably wouldn’t have the disease or spread it. But Haas thinks this might not be long enough to protect people from the latest cases.
“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,” warns Haas.
When Haas analyzed Ebola outbreaks in the Congo in 1995 and in West Africa during the past year, he found there’s a 12 percent chance people could still be infected even if they didn’t get sick within 21 days. Therefore, he thinks the CDC should rethink — and probably lengthen — the time people exposed to Ebola should be quarantined.
“While the 21-day quarantine value, currently used, may have arisen from reasonable interpretation of early outbreak data, this work suggests reconsideration is in order and that 21 days might not be sufficiently protective of public health,” Haas says.
“Recent studies conducted in West Africa have demonstrated that 95% of confirmed cases have an incubation period in the range of 1 to 21 days; 98% have an incubation period that falls within the 1 to 42 day interval. WHO is therefore confident that detection of no new cases, with active surveillance in place, throughout this 42-day period means that an Ebola outbreak is indeed over,” the WHO report states. It does not identify what happens in the other 2 percent of cases.