. 2019 Dec 10;4(6):e001878. doi: 10.1136/bmjgh-2019-001878

Table 4.

Systematic and grey literature review on event-based surveillance in the field: structure and components of EBS systems (n=13)

Publication	Components	Data flow	Integration into routine surveillance	Feedback to stakeholders	Response mechanisms	Resources needed
Outbreak setting	Ratnayake et al (2016)¹⁹ and Stone et al (2016)¹⁷ and ERC (2015)²⁰	Notifier: Community health monitors (CHMs). CHM were volunteers or existing community health workers (CHWs), who received training to detect the six trigger events. Assigned to villages. Receiver: Community surveillance supervisors (CSSs) with assigned a larger area. Verification: CSS, sometimes with support from community health officers (CHOs). CHOs were trained professionals in the public health system. Standard verification process not specified. A standard alert log included: type of alert, age, sex, location and action taken as a result of the alert and if District Ebola Response Centre (DERC) was notified. Risk assessment: Not applicable. Response: Any verified suspect events were reported to local DERC for follow-up. Local social mobilisation teams were notified to provide health education activities. Data collection and transmission: Mobile phones. All CEBS staff received phones and phone credit.	CHM notified→CSS verified and kept log→CHO support verification if needed→local DERC responds. Second additional data flow: CSS→district surveillance supervisor→the national CEBS coordination in Freetown.	Alerts that remained suspect after verification were reported to DERC for response.	CEBS district lead confirmed final alert status with the DERC database. Feedback mechanism not specified.	Response by DERC. Case investigation.	Staff: 7416 CHM, 137 surveillance supervisors. Costs: Start-up costs: US$1.3 million. Monthly costs US$129 000 covered training, telephones, motorbikes, fuel and incentives.
	Lee et al (2016)¹⁸	Notifier: (a) Anyone, nationwide for National Call Centre; (b) anyone in the prefecture for Local Alert Number. Receiver: (a) National Call Centre; (b) Local Alert Number. Verification: (a)+(b) prefecture is informed about the call. Verification algorithm not specified. Risk assessment and response: (a)+(b) prefecture is informed about the call. Data collection and transmission: Not specified.	(a) National Call Centre→dispatch team→prefecture. (b) Local Alert Number→prefecture.	Not specified.	Not specified.	Not specified.	Not specified.
	Miller et al (2015)²¹	Notifier: Anyone, nationwide. Volunteers encouraged public to report to the hotline during 3-day campaign. Receiver: Hotline. Verification: District Ebola Response Teams (DERC). Verification algorithm not specified. Risk assessment and response: DERC. Data collection and transmission: Hotline.	Public→Hotline→District-level Ebola response teams.	Information received is shared with usual state or district Ebola surveillance officers.	Not specified.	Case investigations and follow-up actions: Transport of ill persons. Safe and dignified burials.	Not specified.
	Santa-Olalla et al (2013)²⁵	Notifier: All partners (UN response clusters activated). Field teams reported daily, including zero-reporting. Receiver: “The operational hub of the A&R System was in Port-au-Prince, where alerts were received by the national alert team”. Verification: A&R coordinator or field teams or partners. Information received from ‘official or reliable sources’ was considered verified. All other information was verified. Risk assessment: Assessment by field teams. The assessment consisted of “(a) assess the public health risk posed by the reported event, (b) assess the need for and urgency of such a response, and (c) define the type of response and appropriate partners”. Response: Coordinated by A&R coordinator at national hub. In the field through field teams and ministry of health staff. Data collection and transmission: Telephone and email.	From any partner/field teams→operational hub in Port-au-Prince→field teams for assessment.	A&R system complements existing national surveillance system.	Daily alerts bulletin sent to response partners: alerts and hotspots and assessment of the need for response. Alert and responses also in a weekly bulletin with IBS data.	The system was set up to “organise a rapid response with partners to provide immediate support based on needs identified in the field (eg, supplies, training, social mobilisation, water, and sanitation)”.	Staff: National alert team and 5–8 PAHO/WHO field teams, broad network of partners. UN response cluster mechanism activated.
Routine setting	Clara et al (2018)¹⁴ and (2018)¹³	Notifier: 7167 village health workers (VHWs) and health collaborators (HCs) received training, phone minutes and communication materials. HCs are mostly important community members. Information source of signals: VHW, community members, teachers, pharmacy, clinics, media, office, factories, religious leaders, healers, others. Receiver: Commune Health Station (CHS). Verification: Initial verification: CHS. Comprehensive verification: District Health Centre (DHC). Verification algorithm not specified. Risk assessment: DHC. Response: Provincial Preventive Medicine Centres (PPMC) and/or Regional Institutes. Data collection and transmission: Phone, email, in person.	VHW/HC→CHS→DHC→PPMC→Regional Institutes→General Department of Preventive Medicine.	Complete integration into IBS system. IBS information flow and organisational structure used. Personnel received extra training. VHW existed in theory previously; structure revitalised.	DHC and CHS conduct regular meetings with VHW to ensure a feedback loop is completed.	Not specified. In case study: case finding and laboratory testing of food.	Training and training materials. One-off funding of communication material and infrastructure improvements. All staff positions previously existed.
	Merali et al (2018)	Notifier: Community CBS volunteers Receiver: Public health personnel at local health facility and district, regional, national level Verification, risk assessment and response: not specified. In the case study, district level conducted investigation and response. Data collection and transmission: Tools to report were distributed but not specified.	CBS volunteer→health facility→district→regional→national. Communication with veterinary side at district, regional and national level.	Complete integration into IDSR. Personnel received additional training. Community volunteers existed before.	Not specified.	Not specified.	Not specified beyond training, training materials and reporting tools. Roles of staff existed before.
	Larsen et al (2017)¹⁵ and (2016)¹⁶	Notifier: Community-based volunteers (CBVs) recruited from their communities and trained in event definitions and on how to report using SMS text messages with specified codes for reporting. CBVs reported suspect cases and measures taken on community level. Receiver: CBVs inform volunteer surveillance supervisors (VSSs). Verification: VSS. Verification algorithm not specified. Risk assessment: VSS informs community health officer (CHO) and assess the event together. Response: CHO reports to DERC/DHMT to initiate response. Data collection and transmission: SMS to a local number that is synced with online data collection tool Magpi. The information is automatically analysed in an analytical visualising database.	CVS→VSS→CHO→DERC/DHMT.	VSS reaches out to CHO, who channels the information into the routine surveillance and response system.	Not specified.	DERC/DHMT/health facility.	Not specified.
	Toyama et al (2015)²²	Notifier: Health Development Armies (HDAs)=volunteer-based community health team. Received training on EBS by health extension worker (HEW). Report EBS to health centre (HC). HEWs, who work at health posts and serve about 5000 people, also reported EBS to HC. Other information sources of signals: community, health post workers and others. HC also report into routine indicator-based surveillance. Receiver: HC surveillance focal person at each health facility registers rumours in rumour log book. Verification: Initial Verification: HDAs and HEWs. Assist if needed: Surveillance officers at the district health office. Verification algorithm not specified. Risk assessment: Not specified. Response: Surveillance officers at the district health office instruct response activities and communicate with zonal and regional health departments for further assistance. Data collection and transmission: Not specified.	HDA/HEW/other source→HC surveillance focal person→surveillance officer at district health office.	All roles existed before the rumour log book was introduced, the system was integrated into the routine surveillance system.	Not specified.	Case management, active case finding, vaccination, patient referral.	“The cost of establishing the system was minimal, requiring only a brief orientation for the surveillance focal persons and printing and distribution of the rumour logbooks to the HCs”.
	Oum et al (2005)²⁶	Notifier: Lay VHV chosen by village elder or health facility staff, receiving training, incentive and supervision. "A series of 3 day initial training workshops was held for both VHVs and health staff at each project site shortly before the implementation of the system. It was followed by a monthly half day of refresher training separately for VHVs and health staff and further training in collation and analysis of data for the health staff”. Receiver: Health centre staff. Verification: Not specified if verification was undertaken. Verification algorithm not specified. Risk assessment: Operational district office. Response: Operational district office and local health centre staff. Data collection and transmission: Not specified.	VHV→dedicated health centre staff→operational district staff→provincial health department.	“built on the existing health system and resources, following the Ministry of Health policy and strategy to strengthen the Operational District structure”.	Monthly meeting between VHV and focal points at health centre discussed data, decisions, response.	Outbreak investigation; implementation of control measures.	Travel costs, per diem, food, free medical care for VHVs. Annual cost ~US$0.5 per capita including visits from Phnom Penh for training, supervision, and evaluation.
	Naser et al (2015)²⁴	Notifier: Any physician in sentinel hospitals. Receiver: Surveillance physicians in sentinel hospitals. Verification: Institute of Epidemiology, Disease Control and Research (IEDCR) of the Government of Bangladesh, with the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). Verification through standard questionnaire. Risk assessment and Response: IEDCR and icddr,b. Data collection and transmission: Not specified.	Physician→surveillance physicians→IECDR and icddr,b.	Runs parallel to routine IBS.	Surveillance physicians. IEDCR and icddr,b investigation teams.	Outbreak investigation, active case finding, collect detailed exposures, determine epi link between cases.	Not specified.
	Sharma et al (2009)²⁷	Notifier: Healthcare workers and health professionals. Receiver: Call centre staff. Call centre provides information to state and district surveillance officers for assessment and response. Verification, Risk assessment and Response: State/district surveillance officers. Verification algorithm not specified. Data collection and transmission: 24/7 toll-free call centre, available in multiple languages.	Healthcare workers→Call centre→State/district surveillance officers.	Information received is shared with state or district surveillance officers.	Not specified.	Not specified.	Cost and staff intensive. 65% of call centre budget spent on human resources.
	Tante et al (2015)²³	Notifier: Anyone: media, health workers or non-governmental organisations and other informal channels. Receiver, Verification and Verification algorithm, Risk assessment, Response: Not specified. Data collection and transmission: Formal reporting system, phone calls, text messages any type of reporting.	Entry at any point into the national surveillance system.	Established to complement the national IBS system. During disasters, syndrome-based system is added.	Not specified.	Not specified.	Not specified.
	Dagina et al (2013)²⁸	Notifier: Any source, including health workers, non-governmental organisations, embassies, media and general public. No specific training mentioned. Receiver: EBS coordinator within the Command Centre of the Communicable Diseases Surveillance and Emergency Response Unit of National Department of Health (NDOH). Verification: EBS coordinator verifies events reported from non-health sources by contacting the nearest health authorities or provincial health offices (PHOs) who are responsible for disease surveillance and control. Structured and standardised report and assessment form available for documentation of transmitted information and verification. Risk assessment: EBS coordinator provides guidance to PHO. Response: Primarily PHO. Support from higher levels up on request. Occasionally third parties. Data collection and transmission: Not specified.	Any source→EBS coordinator→PHO. “By routing data directly from the ground level to the national level, the system bypasses established reporting channels, that is, from local/district to provincial to national levels”.	Runs in parallel to existing system. EBS coordinator reaches out to existing system for verification and response.	“All events investigated through the EBS system are reported back to stakeholders(…)through a weekly National Surveillance Bulletin”.	Outbreak investigation. Not specified.	Staff: 2 part-time staff members on national level.

A&R, alert and response ; CBS, community-based surveillance; CBV, community-based volunteer; CEBS, community-event-based surveillance; CHM, community health monitor; CHO, community health officer; CHS, commune health station; CHW, community health worker; CSS, community health supervisor; DERC, District Ebola Response Centre; DHC, district health centre; EBS, event-based surveillance; HC, health centre; HEW, health extension worker; IBS, incicator-based surveillance; PPMC, Provincial Preventive Medicine Centre; VHW, village health workers; VSS, volunteer surveillance supervisors.