Via The New York Times: Fewer Ebola Cases Go Unreported Than Thought, Study Finds. Excerpt:
Transmission of the Ebola virus occurs mostly within families, in hospitals and at funerals, not randomly like the flu, Yale scientists said Tuesday, and far fewer cases go unreported than has previously been estimated.
That implies, they said, that the epidemic is unlikely to reach the gloomy scenarios of hundreds of thousands of cases that studies released in September had forecast were possible; the most pessimistic one, from the Centers for Disease Control and Prevention, had predicted up to 1.4 million cases by late January.
As of Monday, there were 18,464 confirmed cases in Liberia, Sierra Leone and Guinea, with 6,841 deaths, according to the World Health Organization, far more than from all the previous Ebola outbreaks combined.
The new study, led by epidemiologists from the Yale School of Public Health, was published online by the journal Clinical Infectious Diseases. Scientists from Texas, Brazil and the Liberian Health Ministry contributed to the research.
The researchers said they had too little data to predict how many West Africans could eventually be infected, but enough to show that the dire predictions were inaccurate.
In a brief written response, the C.D.C. said that its September projection was “a first attempt to better understand to what extent underreporting was occurring in West Africa.” The new study, the agency said, “further refines our understanding, and C.D.C. applauds the method.”
The worst-case estimates made in September by the C.D.C., the World Health Organization and others were based on what would happen if the world did not mount an effective response. In the months since, donors have committed hundreds of millions of dollars and thousands of soldiers have been sent into the region, while doctors and nurses have volunteered to help.
By looking at virus samples gathered in Sierra Leone and contract-tracing data from Liberia, the scientists working on the new study estimated that about 17 percent of cases in West Africa go unreported, up to a maximum of 70 percent. That is far fewer than earlier estimates.