Table 1.
Summary of outbreaks of suspected cholera cases reported in sub-Saharan Africa, January 2010 to January 2020.
| Outbreaks reported at first-level administrative units | Outbreaks reported at second-level administrative units | Outbreaks reported at third-level administrative units | |
|---|---|---|---|
| Metrics based on suspected cholera cases | |||
| Number of outbreaks | 62 | 692 | 245 |
| Outbreak threshold,weekly incidence per 100,000 people (IQR) |
0.7 (0.7-2.0) |
0.7 (0.7-2.8) |
1.7 (1.7-12.8) |
| Median outbreak size, cases (IQR) | 620 (251-2,191) |
182 (70-449) |
100 (42-234) |
| Median epidemic durations, weeks (IQR) | 12 (8-19) |
13 (8-19) |
12 (8-16) |
| Median time to epidemic peak, weeks (IQR) | 4 (3-5.5) |
4 (3-6) |
3 (3-5) |
| Median proportion of suspected cases reported during the peak week (%) (IQR) | 19.1 (14.8-29.7) |
23.5 (16.4-34.2) |
28.8 (20.5-38.1) |
| Median weekly incidence during the peak week per 1000 people (IQR) | 0.1 (0.03-0.2) |
0.2 (0.1-0.5) |
0.5 (0.2-1.5) |
| Median early outbreak reproductive number (range) | 1.8 (1.2-2.9) |
1.8 (1.1-3.5) |
1.9 (1.02-3.2) |
| Median attack rate per 1000 people (IQR)b | 0.5 (0.2-1.2) |
0.8 (0.3-2.4) |
2.0 (0.6-6.4) |
| Metrics based on cholera-associated deathsa | |||
| Number of outbreaks with reports of deaths | 37 | 646 | 193 |
| Median case fatality risk (%)(IQR) | 1.2 (0.4-2.1) |
1.6 (0.3-4) |
0 (0-0.9) |
| Population-weighted case fatality risk (%)c | 0.7 | 1.9 | 0.8 |
This table presents the key epidemic metrics of outbreaks by different administrative reporting units, including outbreak size, duration, time to outbreak peak, initial reproductive numbers during the first epidemic week, attack rate, and CFRs.
N.B. Outbreaks with reports of deaths may not have documented this information systematically, so these results are highly sensitive to reporting biases.
Only outbreaks with valid population estimates are included. There were 62 outbreaks at the first-level administrative units, 657 outbreaks at the second-level units, and 281 outbreaks at the third-level units.
Only outbreaks with reports of deaths and valid population estimates are included. There were 36 outbreaks at the first-level administrative units, 610 outbreaks at the second-level units, and 229 outbreaks at the third-level units.
CFR = case fatality risks; IQR = interquartile range.