Table 3.
Impact of LPM closure on the risk of H7N9-infection in humans
| Study | Intervention | Data source | Reported outcome | Location | Date of implementation | LPM closure effectiveness* |
|---|---|---|---|---|---|---|
| (Chow ell et al., 2013) | LPM closure and bird culling | Official notifications of laboratory-confirmed H7N9-cases reported to CDC through national surveillance system between March 1st and May 20th, 2013 (n=73) | Observed daily H7N9-incidence rate after LPM closure compared to incidence rate estimated according to an exponential model fitted to the daily case time series prior to the intervention | Shanghai and Zhejiang provinces | April 6th, and 16th, 2013, respectively | Not reported§ |
|
| ||||||
| (Yu et al.,2014) | Closure of 780 LPMs, depopulation and disinfection | Illness onset data of laboratory-confirmed and hospitalized H7N9-cases announced by China CDC until June 7th, 2013 (n=60) | Reduction in mean daily number of infections associated with complete LPM closure (95% CrI) | Shanghai | April 6th, 2013 | 99% (93%–100%) |
| Nanjing | April 8th, 2013 | 97% (81%–100%) | ||||
| Hangzhou | April 15th/24th, 2013 | 99% (92%–100%) | ||||
| Huzhou | April 11th-21st, 2013 | 97% (68%–100%) | ||||
|
| ||||||
| (Lau et al., 2014) | LPM closure | Officially announced laboratory-confirmed H7N9-cases from Chinese CDC and from three other line lists constructed with publicly available information, compiled based on reports of laboratory-confirmed H7N9-cases between April 10th and May 31st, 2013 | LPM closure effectiveness calculated as 1 minus the ratio of H7N9-incidence after LPM closures versus incidence since first case (p-values from likelihood ratio tests) | Shanghai | April 6th, 2013 | China CDC: 94% (<0.001) HealthMap: 93% (<0.001) Virginia Tech: 96% (<0.001) Flu Trackers: 94% (<0.001) |
| Nanjing | April 8th, 2013 | China CDC: 99% (0.007) HealthMap: 100% (0.034) Virginia Tech: 98% (0.010) Flu Trackers: 64% (0.328) |
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| Hangzhou | April 15th, 2013 | China CDC: 100% (<0.001) HealthMap: 99% (<0.001) Virginia Tech: 99% (<0.001) Flu Trackers: 100% (<0.001) |
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|
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| (Wu et al., 2014) | LPM closure for ≥7 consecutive days | Confirmed H7N9-cases between 14 days before LPM closure or onset date of first confirmed local case in 2014 (whichever later) and last day of LPM closure or March 7th, 2014 (whichever earlier); data source not reported (n=69) | LPM closure effectiveness (95% CI), calculated as 1 minus IRR | Guangdong and Zhejiang provinces | Different closing dates in each market between January and early March 2014 | 97% (87%–100%) |
|
| ||||||
| (Kucha rski et al., 2015) | LPM closure | Symptom onset data; data source not reported | Reduction of market spillover hazard, i.e. the risk of animal-to-human infection (95% CrI) | Shanghai province | First wave (2013): 99% (95%–100%) | |
| Zhejiang province | January 22nd–26th, 2014 |
First wave (2013):
99% (97%–100%) Second wave (2014): 97% (92%–99%) |
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| Jiangsu province | First wave (2013): 97% (80%–100%) | |||||
| Guangdong province | Guangdong: Guangzhou: February 16th-28th 2014; other cities: 2week closure in the same period | Second wave (2014): 73% (53%–89%) | ||||
*
LPM closure effectiveness expressed as 1-IRR; IRR= ratio of H7N9-incidence rate after LPM closure/H7N9-incidence rate before LPM closure
§
Quantitative estimate not provided; authors reported a significant deceleration after LPM closure, outside of the confidence bounds predicted by the pre-intervention model
LPM= live poultry market
CDC= Center for disease control and prevention
95%CrI= 95% Credibility interval
95% CI= 95% Confidence interval