Ebola Virus Disease (EVD) 2014 - Nicholas P. Jewell Departments of Statistics & School of Public Health (Biostatistics) University of California, Berkeley

1. Ebola Virus Disease (EVD) 2014
Nicholas P. Jewell
Departments of Statistics &
School of Public Health (Biostatistics)
University of California, Berkeley
October 16, 2014

2. Economist August 2 2014
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© Nicholas P. Jewell, 2014

3. WHO October 10, 2014
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Source: WHO Ebola Response Roadmap Update, Oct 10 , 2014

4. WHO, October 10, 2014
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5. WHO October 10, 2014
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6. The trends aren’t good
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WHO Ebola Response Team, Sept 26, 2016, NEJM

7. And that’s just what we know
“Since the beginning of the outbreak more than six months ago,
the Sierra Leone Health Ministry reported only 10 confirmed
Ebola deaths here in Freetown, the capital of more than one
million people…. But the bodies pouring in to the graveyard tell
a different story. In the last eight days alone, 110 Ebola victims
have been buried at King Tom Cemetery, according to the
supervisor, Abdul Rahman Parker, suggesting an outbreak that
is much more deadly than either the government or international
health officials have announced.”
- “Fresh Graves Point to Undercount of Ebola Toll”, New York Times, Sept 22, 2014
© Nicholas P. Jewell, 2014
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8. What Do We Know?
Transmission
© Nicholas P. Jewell, 2014
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Country Basic
Reproductive
Number
Reproductive
Number,
September
Guinea 1.71
(1.44, 2.01)
1.81
(1.60, 2.03)
Liberia 1.83
(1.72, 1.94)
1.51
(1.41, 1.60)
Sierra Leone 2.02
(1.79, 2.26)
1.38
(1.27, 1.51)
WHO Ebola Response Team, Sept 26, 2016, NEJM

9. What Do We Know
Case Fatality Rate
• Early estimates (around 50 percent)
suggested virus was less lethal. But these
were based on known deaths and total
cases
• New estimates using only cases that have
proceeded to recovery or death show
70.8% (95% CI, 69% to 73%) fatalities
© Nicholas P. Jewell, 2014
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10. What’s coming? Model Projections
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NEJM Sept 23, 2014 (WHO) © Nicholas P. Jewell, 2014

11. …. or worse
MMWR Sept 23, 2014 (CDC) 11
© Nicholas P. Jewell, 2014

12. What if We Intervene More Successfully?
MMWR Sept 23, 2014 (CDC)
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© Nicholas P. Jewell, 2014

13. Mobile Clinic, Sierra Leone
© Nicholas P. Jewell, 2014
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14. Interventions
• There is no therapy or vaccine as yet
(other than palliative care). This is a
public health response:
– Treatment centers (treat and isolate patients)
– Curfews
– Quarantines
• All attempt to limit transmission.
• Are they helping?
© Nicholas P. Jewell, 2014
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15. What works?
• How do you evaluate interventions in a
crisis?
– How do we benchmark?
– What before/after data is available?
– What natural experiments?
• Some ideas are just bad
– Limiting air travel may impede response to the
epidemic
© Nicholas P. Jewell, 2014
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16. What Do We Need to Know?
• Under-reporting
– How bad is it?
– Is level of reporting changing over time?
• This would affect projections
• Are there individual variations in
infectiousness?
– Is their enough chain data to assess this (i.e,
variations in serial interval, secondary
infections across individuals)
• Genetic info? Mutations?
© Nicholas P. Jewell, 2014
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17. References
• WHO Ebola Response Team, “Ebola Virus Disease in West Africa
—The first 9 Months of the epidemic,” NEJM, 2014, September 23,
DOI: 10.1056/NEJMoa1411100
• Metlzer, M. et al., “Estimating the future number of cases in the
Ebola epidemic—Liberia and Sierra Leone, 2014-15,” MMWR,
63(03), September 26, 2014,1-14
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© Nicholas P. Jewell, 2014