Ebola Virus Disease (EVD) 2014

Nicholas P. Jewell Departments of Statistics &

School of Public Health (Biostatistics) University of California, Berkeley

October 16, 2014

Economist August 2 2014

2

© Nicholas P. Jewell, 2014

WHO October 10, 2014

3

Source: WHO Ebola Response Roadmap Update, Oct 10 , 2014

WHO, October 10, 2014

4

WHO October 10, 2014

5

The trends aren’t good

6

WHO Ebola Response Team, Sept 26, 2016, NEJM

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

7

What Do We Know?Transmission

© Nicholas P. Jewell, 2014

8

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

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

9

What’s coming? Model Projections

10 NEJM Sept 23, 2014 (WHO) © Nicholas P. Jewell, 2014

…. or worse

11 MMWR Sept 23, 2014 (CDC)

© Nicholas P. Jewell, 2014

What if We Intervene More Successfully? MMWR Sept 23, 2014 (CDC)

12

© Nicholas P. Jewell, 2014

Mobile Clinic, Sierra Leone

© Nicholas P. Jewell, 2014

13

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

14

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

15

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

16

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

17

© Nicholas P. Jewell, 2014