Table 1 Summary of included studies
Authors, Date | Disease (country) | Types of intervention | Types of measures | Outcome measures | Effectiveness/rapidity | Main limitations |
|---|---|---|---|---|---|---|
Section I - Case studies | ||||||
Santa-Olalla et al. 2013 [19] | Cholera (Haiti) | Alert & response (A&R) system; identification and assessment of cholera alerts and hotspots; organization of a rapid response with partners to provide immediate support based on needs identified in the field (e.g., supplies, training, social mobilization, water, and sanitation) | Healthcare provision; epidemiological investigation and/or surveillance; community-based measures | Not mentioned | Positive (A&R system showed how the rapid detection of cholera alerts was a key element in identifying outbreaks and in directing and coordinating urgent response) | No clear outcome to evaluate the effectiveness of the A&R system |
Gazin and Louissaint 2011 [20] | Cholera (Haiti) | Awareness campaign; oral rehydration points; cholera treatment centres; water purification | Healthcare provision; community-based measures; environmental and sanitary interventions | Fatality rate | Positive (mortality rate < 1% in treatment centres; strategy and coordination qualified as ‘efficient’) | Few outcome measures; basic evaluation of effectiveness |
Guévart et al. 2005 [21] | Cholera (Cameroon) | Case management; preventive antibiotic treatment of all patient contacts; enhanced surveillance system | Healthcare provision; epidemiological investigation and/or surveillance | Incidence of notified cases from special units | Positive (no new cases after the implementation of containment measures) | The role of large-scale treatment of antibiotic prophylaxis in ending the cholera outbreak could not be ascertained |
Bin Yunus et al. 2001 [22] | Dengue (Bangladesh) | Development of national guidelines for clinical management; training of doctors; reorientation of specialists; entomological mapping; documentation of cases; operational studies for testing case definitions; collection of sero-evidence; community-based measures (community empowerment for prevention and control) | Healthcare provision; epidemiological investigation and/or surveillance; community-based measures | No clear outcome | Positive (successful operationalization of action plans) | No clear objective |
Maciel-de-Freitas et al. 2014 [23] | Dengue (Brazil) | Standard chemical and environmental vector control measures | Environmental and physical interventions | House index a; number of cases (no information whether laboratory validated); mean incidence | Negative (only slight decrease in vector density; no significant change in seasonal dynamics of dengue) | No clear objective; some highly-productive cryptic containers were not inspected by vector control professionals |
Khan and Abbas 2014 [24] | Dengue (Pakistan) | Creation of a provincial cabinet committee; data collection; training of professionals; awareness campaigns; improvement of health infrastructure; appointment of public health officers | Healthcare provision; epidemiological investigation and/or surveillance | Numbers of reported clinical cases | Positive (252 reported cases of dengue in 2012 in Lahore with no deaths) | Limited outcome measures |
Nyenswah et al. 2015 [25] | Ebola virus disease (Liberia) | Active case-finding; contact tracing; effective triage within the healthcare system; rapid isolation of symptomatic contacts; home-based and community quarantine; decentralized management of outbreak activities | Epidemiological investigation and/or surveillance; healthcare provision; environmental and sanitary interventions | No outcome measures | Positive (more complete contact tracing, more prompt isolation of symptomatic patients in the second and third generations of transmission, increased survival, and reduced transmission in the community) | Methodology unspecified |
Althaus et al. 2015 [26] | Ebola virus disease (Nigeria) | Surveillance and contact tracing; case management; screening of all arrivals/departures in and out of the country by land, air, and sea; social mobilization; use of technology for innovative applications in the EOCs | Healthcare provision; Epidemiological investigation and/or surveillance | Fitting a transmission model to Nigeria outbreaks | Positive | Methodology and outcomes measures not specified |
Webster-Kerr et al. 2011 [27] | Malaria (Jamaica) | Early detection and prompt treatment of cases; vector control; public education; community-based surveillance; intersectoral collaboration | Healthcare provision; epidemiological investigation and/or surveillance; community-based measures; environmental and sanitary interventions | Number of laboratory confirmed cases | Positive (only one of 358 cases who had a post-treatment smear on day 7 had a persistent asexual parasitaemia, while none of the 149 persons who had a follow-up smear on day 28 was positive) | No individual assessment of measures’ efficacy; data were observational rather than experimental |
Brostrom et al. 2011 [28] | Multi-drug resistant TB (Micronesia) | Case identification; contact investigation; creation of an action plan; construction of MDR-TB isolation units; training of community health workers; enhanced access to national and international subject-matter experts | Healthcare provision; epidemiological investigation and/or surveillance | TB-related mortality rates | Positive (in the 12 months following implementation of these programmatic improvements, TB mortality in Chuuk dropped from 11% of all TB cases to less than 1%) | Limited outcome measures |
Section II - Descriptive studies | ||||||
Shen and Niu 2012 [29] | A/H1N1 influenza (China) | Screening at borders; isolation; quarantine; large-scale reactive vaccination campaign | Healthcare provision; epidemiological investigation and/or surveillance; environmental and sanitary interventions | Incidence of laboratory confirmed H1N1 influenza; mortality rates | Positive (epidemic curve showed that control measures of containment and vaccination reduced H1N1 morbidity/mortality) | Laboratory confirmed cases analyzed represented a small subset of cases of pandemic H1N1 influenza during the period, as only laboratory-confirmed cases were analyzed |
Guévart et al. 2007 [30] | Cholera (Cameroon) | Follow-up of notifications; bacteriological monitoring; antibiotic distribution; large-scale targeted antibiotic prophylaxis | Healthcare provision; epidemiological investigation and/or surveillance | Proportion of contacts among new cases; development of resistant strains | Uncertain (antibiotic prophylaxis limited inter-human transmission of cholera but no impact on the epidemic was shown) | New cases of cholera were not always the consequence of contact with a case, instead resulted from environmental exposure (e.g., contaminated water), such that it was difficult to measure the impact of a preventive strategy at the population level |
Peng et al. 2012 [31] | Dengue (China) | Vector surveillance; human surveillance; chemical and environmental vector control measures; community-based measures (prevention, public awareness) | Epidemiological investigation and/or surveillance; community-based measures; environmental and sanitary interventions | Breteau index b; number of dengue cases | Positive (drop of the Breteau index, no more dengue cases reported since September 14, 2010) | No clear objective; only suspected dengue cases were sent for laboratory confirmation |
Maciel-de-Freitas et al. 2014 [32] | Dengue (Brazil) | Intensification of standard chemical and environmental vector control measures | Environmental and physical interventions | Infestation levels, number of eggs in ovitraps | Negative (infestation levels only slightly reduced) | Reasons for low efficacy remain unclear due to several uncontrolled variables |
Seidahmed et al. 2012 [33] | Dengue (Sudan) | Health education; house inspection campaign by community volunteers; house inspection by health workers; space spraying; larviciding | Healthcare provision; community-based measures; environmental and sanitary interventions | Entomological indices; dengue incidence of laboratory confirmed cases | Both positive and negative, depending on types of measures | No individual assessment of control measure |
WHO Ebola Response Team 2016 [34] | Ebola virus disease (Guinea, Liberia, and Sierra Leone) | Case-finding; contact tracing; cases isolation; specially designed Ebola treatment centres; supportive clinical care; safe burials | Healthcare provision; epidemiological investigation and/or surveillance | Does not apply (purely descriptive study) | Positive | Did not explicitly evaluate the impact of the interventions |
Abramowitz et al. 2015 [35] | Ebola virus disease (Liberia) | Community-based measures (prevention; training; surveillance; response and treatment; post-outbreak measures) | Community-based measures | Does not apply (qualitative study) | Negative (interventions regarded as necessary, but less desirable than a well-supported health-systems based response; community health messaging failed to provide the needed practical information and training) | Large number of participants in focus groups; questions were posed as hypothetical rather than concerning local experiences and actions |
Okware et al. 2015 [36] | Ebola virus disease (Uganda) | Appointment of a national task force; community mobilization; community-based case search, isolation, and public education; improvement of health infrastructures; early detection and action | Healthcare provision; Epidemiological investigation and/or surveillance; community-based measures; environmental and sanitary interventions | Numbers of laboratory confirmed cases; case fatality rate; delays in early detection | Negative in urban settings | Limited outcome measures; methodology not mentioned; did not explicitly evaluate the impact of the interventions |
Iroezindu et al. 2015 [37] | Lassa fever (Nigeria) | Contact tracing; risk assessment; decontamination of the environment; establishment of a phone-based alert management system; provision of post-exposure prophylaxis for exposed individuals | Healthcare provision; epidemiological investigation and/or surveillance; environmental and sanitary interventions | Number of secondary cases | Positive (no secondary case of LF occurred) | |
Ajayi et al. 2013 [38] | Lassa fever (Nigeria) | Coordination; active surveillance and community mobilization; suspect and contact evaluation; case management | Healthcare provision; epidemiological investigation and/or surveillance; community-based measures | Case fatality rate; timing of outbreak detection | Positive | Basic evaluation of effectiveness |
Pang et al. 2003 [39] | Severe acute respiratory syndrome (China) | Set up of fever clinics; training health care workers; closure of all public entertainment sites; construction of designated SARS hospitals with air extraction fans on windows or walls; quarantine of close contacts; self-quarantine | Healthcare provision; environmental and sanitary interventions | Attack rate; number of case; time lag between illness onset and hospitalization | Positive (multiple control measures implemented in Beijing likely led to the rapid resolution of the SARS outbreak) | Could not determine which intervention(s) was the most effective because of the simultaneous and overlapping implementation of multiple control measures; SARS attack rates might have been falsely elevated due to the unavailability of laboratory testing; the 5 districts selected to evaluate contact tracing and quarantine might not have been representative of all of Beijing. |
Liang et al. 2005 [40] | Severe acute respiratory syndrome (China) | Infection source control; timely hospital admission and safe transfer of all identified cases; classified isolation of all contacts and suspect cases; centralized treatment and personal protection equipment | Healthcare provision; environmental and sanitary interventions | Interval between disease onset and hospital admission | Positive (notable shortening of the interval between disease onset and notification) | Limited information on control measures; only measured the aggregated effect of multiple intervention measures |
Section III - Analytic studies | ||||||
Sévère et al. 2016 [41] | Cholera (Haiti) | Reactive vaccination campaign | Healthcare provision | Rates of culture-confirmed cholera, severe dehydration at admission | Positive (only 18 of the 52 357 vaccine recipients (0.034%) had culture-confirmed cholera compared with 370 of the 17 643 unvaccinated (2.09%); no case of cholera had been documented in a vaccine recipient since September 2013). | Study not designed as a case-control study; impact of natural immunity to cholera not taken into account; heterogeneity of risk for cholera within the catchment area; impact of migration; passive surveillance for acute diarrhea cases; probable that asymptomatic or mild cases did not present to the treatment centres; migration of population in and out of the slum may also impact the estimated herd immunity; impact of interventions may be difficult to differentiate. |
Ordóñez González et al. 2011 [42] | Dengue (Mexico) | Chemical vector control measures | Environmental and sanitary interventions | Mosquito mortality rates (15 min and 24 h after exposure) | Positive (mosquito mortality rates of 78.8% to 96.6% after 15 min of exposure and 98.8% to 100% 24 h after exposure. No mortalities were observed in the controls) | Small sample size (4 houses with 3 cages in each) |
Section IV – Model-based | ||||||
Tang et al. 2012 [43] | A/H1N1 influenza (China) | Contact tracing; campus quarantine | Epidemiological investigation and/or surveillance; environmental and sanitary interventions | Peak time of the epidemic; magnitude of outbreak (number of infectious individuals) | Positive (reduction of A/H1N1 transmission from the campuses into the wider community; delay in timing of peak of infection) | Generalization of findings is limited because of unique features of the social network and academic activities in Chinese campuses |
Pinho et al. 2010 [44] | Dengue (Brazil) | Adult vector control mechanisms | Environmental and sanitary interventions | Number of cases (no information whether laboratory validated) | Negative (reduction in total number of cases; resurgence of the epidemic process (R(t) > 1) as a consequence of susceptible humans) | Limited information on control measures |
Merler et al. 2015 [45] | Ebola virus disease (Liberia) | Deployment of protection kits to households; Ebola treatment units; safe burials | Healthcare provision; environmental and sanitary interventions | Number of projected cases and deaths | Positive (Ebola treatment units may have contributed to halving the number of cases and deaths; deployment of protection kits to about 50% of households may have contributed to further reduce incidence from 30 new cases daily to 10; safer burial practices may have contributed an additional 50% reduction compared to no intervention) | Data availability is limited (some estimates were obtained from previous outbreaks); quantitative assessment of effectiveness and coverage of protection kits was not possible |
Althaus et al. 2015 [26] | Ebola virus disease (Nigeria) | Case isolation; contact tracing; surveillance | Epidemiological investigation and/or surveillance; environmental and sanitary interventions | Change in net reproduction number after implementation of control interventions; risk of outbreak from a single undetected case | Positive (reduction of net reproduction number Rt below unity 15 days (95% CI: 11–21 days) after the arrival of the index case) | Fitting of a deterministic model to a small outbreak (20 cases); assumption that EVD cases are equally infectious throughout their infectious period; did not examine the separate contributions of transmission in healthcare settings and in the community; did not distinguish between different types of interventions; treated the two transmission clusters as a single outbreak |
Kucharski et al. 2015 [46] | Ebola virus disease (Sierra Leona) | Introduction of treatment beds in Ebola holding centres | Healthcare provision | Number of cases averted | Positive (56 600 (95% credible interval: 48300–84 500) Ebola cases were averted in Sierra Leone as a direct result of additional treatment beds) | Lack of quality data on timing and role of different interventions |
Ferrari et al. 2014 [47] | Meningitis (Nigeria) | Case management; strengthening of surveillance; mass vaccination campaigns | Healthcare provision; epidemiological investigation and/or surveillance | Reduction in confirmed meningitis cases | Positive (overall impact of vaccination campaigns ranged from 4 to 12%; vaccination reduced cases by as much as 50% when campaigns were conducted early in the epidemic) | Possible underestimation of campaign impact; provides an estimate of the vaccination campaign impact although rudimentary in its characterization of meningitis epidemiology |
Yip et al. 2008 [48] | Severe acute respiratory syndrome (China) | Information dissemination to the public; quarantine; closure of most public facilities, schools and universities; site surveillance at airport | Epidemiological investigation and/or surveillance; Environmental and sanitary interventions | Daily numbers of confirmed SARS patients | Positive (drop in number of daily infections) | Only measured the aggregated effect of multiple intervention measures; only showed that number of cases started to decline at time of interventions; the study could not determine what measure was the most important factor leading to the reduction |