Scientists say 3% of Ebola victims caused 61% of cases

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Scientists have concluded that if they could have appropriately quarantined about 840 people infected with Ebola in the 2014-15 epidemic that originated in Guinea, Liberia and Sierra Leone, they might have prevented more than 17,000 cases and saved thousands of lives.

The findings are prompting a new look at quarantine of disease “superspreaders” in such situations.

The results come from the study “Spatial and temporal dynamics of superspreading events in the 2014-2015 West Africa Ebola epidemic.”

Published by the Proceedings of the National Academy of Sciences, its authors are Max S. Y. Lau of Princeton, Benjamin Douglas Dalziel of Oregon State, Sebastian Funk of London, Amanda McClelland of Switzerland, Amanda Tiffany of Switzerland, Steven Riley of Imperial College, C. Jessica E. Metcalf of Princeton and Bryan Grenfell of Princeton.

The study found that a small number of superspreaders, about 3 percent of all of the cases, “were responsible, either directly or indirectly, for a substantial proportion (with median 61 percent) of all of the cases generated, highlighting the key role of these superspreaders in driving the epidemic growth.”

“Had the superspreaders been identified and quarantined promptly, a majority of the infections could have been prevented,” the report concluded.

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The epidemic, which reached around the world and even generated cases handled inside the United States, saw more than 28,000 people fall ill, mostly in Guinea, Liberia and Sierra Leone.

About 11,300 died, a mortality rate of about 40 percent.

But if 61 percent of the cases had been suppressed by quarantine of the “superspreaders,” there could have been 17,080 fewer cases and possibly nearly 6,900 fewer deaths.

The study pointed out a “substantial proportion of secondary cases” might have been prevented had these “superspreaders” “been identified and quarantined promptly.”

“The increasing relative importance of superspreading over the later stages of the outbreak … is consistent with the rising availability of hospital beds – that is, later in the outbreak, most infected individuals were able to get a bed at an Ebola treatment center (ETC) and largely did not further transmit; as a result, those superspreaders in the community who did not make it to ETCs may have played an increasingly important role in sustaining the epidemic by generating more secondary cases.”

The report continued: “Our results also suggest that Ebola transmission may have disproportionately affected the local community, because we estimate a relatively short transmission distance. This estimated distance has implications for implementation of regional control measures. Identifying individuals who have the profile (socially or culturally) of being at greater risk of causing superspreading events is crucial for implementing targeted interventions.”

The authors said, “Understanding superspreading can facilitate devising individually targeted control measures, which may outperform population-level measures.”

The scope of the Ebola epidemic in West Africa was unprecedented, and early control measures failed to contain it.

“Superspreading” happens when “certain individuals (i.e. superspreaders) disproportionately infect a large number of secondary cases relative to an ‘average’ infectious individual.”

Similar circumstances were noted in a 2003 outbreak of severe acute respiratory syndrome and the MERS outbreak in the Middle East in 2012.

“Quantifying superspreading is a key step for refining prediction of future epidemics; also, identifying associated risk factors would facilitate implementation of targeted control measures, which may outperform population-level measures,” the scientists wrote.

Doctors Without Borders explained special centers were opened during the outbreak to treat victims and multiple treatments were attempted.

It all was aggravated by an acute shortage of doctors and nurses, the group said.

The CDC Foundation said it was a problem “for the world.”

The agency made more than 3,000 deployments to West Africa and other locations.

Since then, much research has been done on the disease, how it spreads and what can stop it.

A U.S. government agency said it was working on a process that could result in treatments being developed within 60 days of the identification of a pathogen such as Ebola.

The effort was outlined in a report in Joseph Farah’s G2 Bulletin.

Such treatments now sometimes take years to develop, and even flu vaccines generally require one year.

But the Defense Advanced Research Projects Agency said that’s no longer acceptable.

“DARPA’s goal is to create a technology platform that can place a protective treatment into health providers’ hands within 60 days of a pathogen being identified, and have that treatment induce protection in patients within three days of administration,” said Matt Hepburn, a program manager for the effort.

“We need to be able to move at this speed considering how quickly outbreaks can get out of control. The technology needs to work on any viral disease, whether it’s one humans have faced before or not.”

GET FREE E-BOOK RIGHT NOW! Jane Orient, M.D., chief of the Association of American Physicians and Surgeons, has written a comprehensive and crystal-clear e-book on how to protect yourself and your loved ones from dreaded infectious diseases. “EMERGING DISEASES: Protecting Your Family from Pandemics, Viral Threats, and Rogue Vaccines” is available FREE, exclusively to subscribers to WND’s email news alerts. Sign up now for FREE – and you can download Dr. Orient’s e-book, “The Truth About Ebola.”

 

Scientists say 3% of Ebola victims caused 61% of cases
Source: WND