Epidemiology Master Level Quiz

Introduction to Public Health Surveillance Systems

Carlos Castillo-Salgado, MD, JD, MPH, DrPH Johns Hopkins University

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Basic Concepts of Public Health Surveillance

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Basic Concepts of Public Health Surveillance—A Definition of Surveillance

► Surveillance has been defined as the systematic, regular ascertainment of incidence of public health events using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy

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The WHO Definition

► Surveillance is the “systematic collection and use of epidemiologic information for the planning, implementation, and assessment of disease control” (WHO, 1968)

► “Public health surveillance is the continuous, systematic collection, analysis and interpretation of health-related data needed for planning, implementation, and evaluation of public health practice”* (WHO, 2012)

*Source: WHO. Accessed November 29, 2018, at https://www.who.int/topics/public_health_surveillance/en/

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Need for Global Health Security and PH Response

► In the early 21st century, a new major overhaul was proposed for these Regulations, citing the urgent need for increasing global health security and for the coordination of the global public health response to natural disasters and accidental release or deliberate use of biological and chemical agents or radio-nuclear material that can affect global public health

► The newly revised “International Health Regulations” (IHR-2005) were approved by all 194 World Health Organization member states. These health regulations entered into force in 2007.

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New Public Health Surveillance Terms

► Introduction of new key terms ► “Public Health Risk” (PHR) and ► “Public Emergency of International Concern” (PHEIC)

► A global health emergency was defined as an “extraordinary event” which is determined by the following: ► (i) it constitutes a public health risk to other States through the international spread of

disease; and ► (ii) it potentially requires a coordinated international response.

► One of the key goals of the IHR is to monitor the emergence of any “public health emergency of international concern”

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Data Collection for Health Action Flowchart

► Health action ► Investigation ► Control ► Prevention

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Characteristics of PH Surveillance Systems

► Purpose: early warning, tracking, detect changes, alarm

► Administrative level: local, national, global

► Scope: notifiable conditions, sentinel events

► PH event identification: active vs. passive

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Types of Surveillance

► Passive surveillance ► Passive surveillance often gathers disease data from all potential reporting health care

providers—most common type of surveillance

► Active surveillance ► Active surveillance provides stimulus to health care providers in the form of individual

feedback or other incentives

► Sentinel surveillance ► Instead of attempting to gather surveillance data from all health care providers, a

sentinel surveillance system selects, either randomly or intentionally, a small group of health providers from whom to gather data

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Surveillance Methods

► Data collection ► Standardized instruments,

field tested ► Passive surveillance

► Providers are responsible for reporting

► Health department waits to receive reports

► Problem with underreporting

► Active surveillance ► Providers contacted on

regular basis to collect information

► More resource intensive ► Used for outbreaks or pilots

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Why We Need to Create PH Surveillance Systems?

► To address a need for specific information about priority health conditions, public health events, events of potential international concern, health risk factors…

► If health condition, we need to understand its “natural history”

► Severity, extent, group vulnerability, trends…

► Existing surveillance system is not providing the needed information

► Critical and time-sensitive public health problems

► Public and community interest

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Is There a Comprehensive Surveillance System?

► No single comprehensive PH surveillance system is available

► Problems with legacy systems

► Needs are evolving

► Different sources, owners, and data streams

► Ethical and confidentiality issues

► Network of interoperable HIS linked electronically

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Developing Surveillance Systems

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Functions of Surveillance of Communicable Diseases

► Communicable disease surveillance has the following five functions: 1. The early warnings and detection of epidemics to enable rapid investigation and

control 2. The monitoring of trends over time to assess the need for prevention 3. The evaluation of preventive measures 4. The provision of information for service planning and resource allocation 5. The collection of data on rare and newly recognized diseases for research purposes

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Developing a Surveillance System

► Establish objectives

► Identify and develop “standards”

► Develop case definitions

► Identify the unit of surveillance

► Determine data source or data collection mechanism

► Field test methods

► Develop and test analytic approach

► Develop dissemination mechanism

► Assure use of analysis and interpretation for public health action

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What Should Be Under Surveillance?

► Establish priorities based on: ► Frequency (incidence, prevalence, mortality, years of potential life lost [YPLL]) ► Severity (case-fatality, hospitalization rate, disability rate) ► Cost (direct and indirect) ► Preventability ► Communicability ► Public interest ► Public health event of global importance ► Whether the data will be useful for public health action

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Events Requiring Surveillance

► Three diseases were covered by the International Health Regulations: cholera, plague, and yellow fever

► Five diseases were subject to global surveillance: epidemic typhus, influenza, malaria, poliomyelitis, and relapsing fever

► Immunization against six diseases has been part of the WHO Expanded Programme on Immunization: diphtheria, measles, poliomyelitis, tetanus, tuberculosis, and whooping cough

► Infectious diseases of public health importance, new infections, certain occupational diseases

► Other conditions of interest (violence, substance abuse, birth defects)

► Bio surveillance and health security events ► Risk factors and social determinants of health ► Obesity (WHO)

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National Notifiable Diseases Surveillance System (NNDSS)

Source: CDC. National Notifiable Diseases Surveillance System (NNDSS) website.

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US List of Reportable Diseases: Over 120 Reportable Diseases/Conditions

Source: CDC. National Notifiable Diseases Surveillance System (NNDSS) website.

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Public Health Surveillance Methods

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Recognize the Cycle of Public Health Surveillance

► Data collection process ► Pertinent, regular, frequent, timely

► Consolidation and interpretation ► Orderly, descriptive, analytic, evaluative, timely

► Dissemination ► Prompt, to all who need to know (data providers and action

takers)

► Action to control and prevent

► Evaluation of the system

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Surveillance Methods: Case Definition

► Case definition ► Important to clearly define condition ► Ensures same criteria are used by all ► Makes the data more comparable ► Include person, place, time ► May define suspected and confirmed cases ► May include symptoms, lab values, time period, population as appropriate

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Case Definition Examples

► Weak definition—Measles ► Any person with a rash and fever, runny nose, or

conjunctivitis

► Better definition—Measles ► Any person with a fever >101 F, runny nose, conjunctivitis,

red blotchy rash for at least three days, and laboratory confirmation of IgM antibodies

► Clinical, probable, confirmed case

► Outbreak case definition ► Differs from routine surveillance ► Epidemiologically linked

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Main Data Sources

► Vital statistics

► Notifiable diseases

► Registries

► Sentinel surveillance

► Syndromic surveillance

► Surveys

► Administrative data

► Press and TV

► Role of EHR

► Web-based platforms

The material in this video is subject to the copyright of the owners of the material and is being provided for educational purposes under rules of fair use for registered students in this course only. No additional copies of the copyrighted work may be made or distributed.

Types of Public Health Surveillance Systems

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Requirements of New Surveillance Systems

► Need faster and more accurate surveillance for identifying emerging and reemerging infectious diseases

► Technology allows improvement in disease surveillance ► Electronic databases ► Ability to rapidly move data ► Ability to quickly manipulate and analyze data

► Health indicator surveillance ► Using various types of non-traditional data as a surveillance tool to monitor the health

of a community

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Key Features of Early Warning

► Essential features of early warning and surveillance networks are technical expertise support, clear terms of reference, dedicated staff for coordination, generation of useful information for public health action, regular meetings of clients, common data standards, scientific rigor, and problem/data/solution sharing

► Trade-offs between general information and useful information need to be made, and certainty (accuracy and specificity) needs to be balanced versus timeliness and relevance

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Syndromic Surveillance

► Uses pre-diagnostic indicators to identify emerging health problems

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Early Detection Analyses

Need for early detection

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Early Detection of Malaria Foci in Zambia

Early detection of malaria foci for targeted interventions in endemic southern Zambia

Source: Davis, RG, et al. (2011). Malar J, 10, 260. http://dx.doi.org/10.1186/1475-2875-10-260

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Aberration Detection Methods

► Aberration detection methods allow the rapid assessment of changes in frequencies and rates of different health outcomes and the characterization of unusual trends or clusters

Source: Hutwagner et al. (2003). The bioterrorism preparedness and response Early Aberration Reporting System (EARS). J Urban Health, 80(2 Suppl 1), i89–96.

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New PH Surveillance Systems and Networks

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Global Surveillance of Communicable Diseases: The Global Outbreak Alert and Response Network (GOARN)

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Canada— GPHIN

“The GPHIN software application ‘pulls’ relevant articles every 15 minutes from newsfeed aggregators (Al Bawaba and Factiva) based on established search syntaxes that are updated regularly as necessary. The articles are further filtered and categorized into one or more of GPHIN’s taxonomy categories which cover the following:

Animal diseases Human diseases Plant diseases Biologics Natural disasters Chemical incidents Radioactive incidents Unsafe products”

“…primary sources of outbreak information are the global news services. Factiva and the Arab language Al Bawaba. These services operate as news aggregators that provide multiple sources of information through a single access point. Factiva, for example, aggregates news information from nearly 9,000 in 22 languages.”

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Global Networks

Source: HealthMap.org

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HealthMap—Alerts

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PromMED-Mail

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PromMED-Mail/EpiCore

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Flu Near You—Real-Time Surveillance

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Flu Near You Weekly Health Report

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Flu Near You: Community-Based Surveillance

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Types of Non-CD Surveillance Systems

► Behavioral Risk Factor Surveillance ► HIV BSS ► Youth Risk BSS ► Foodborne Diseases Active Surveillance Network

(FoodNet) ► National Violent Death Reporting System

(Butchart. [2006]. Inj Prev, 12[Suppl 2], ii63–ii64.) ► 17 US states funded to conduct active

surveillance ► WHO’s STEPwise Approach to Risk Factor

Surveillance

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Important Steps for a New PH Surveillance System

► Justification of need for new PHS system

► Timeliness: supporting timely local or national public health decisions

► Role of informal networks of epidemiologists

► Points of contact

► Development of secure data platforms

► Develop data quality standards and system protocols

► Confidentiality

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Setting up a Surveillance System

► Tasks 1. Decide on population to be surveilled 2. Decide on objectives and indicators 3. Standardize case definitions and alert thresholds 4. Decide on surveillance approach 5. Identify information sources 6. Identify frequency/time-frame of surveillance 7. Develop data collection, analysis, interpretation, reporting

& dissemination methods/systems

► Organize the system 1. Information flow 2. Human resources 3. Train and supervise surveillance workers

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DHHS: The Secretary’s Operations Center (SOC)

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Surveillance Resource Center

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Contact Information

► Carlos Castillo-Salgado, MD, JD, MPH, DrPH

► Professor of Epidemiology, Director of the Global Public Health Observatory, Director of the Certificate for Public Health Professionals

► Department of Epidemiology

► Johns Hopkins Bloomberg School of Public Health

► [email protected]