Epidemiological Surveillance and Screening

Epidemiological Surveillance

• Ongoing, systematic collection of health data for public health insights.

Surveillance

• Monitors public health trends, detects outbreaks early, and informs policy decisions.

Screening

• Identifies individuals with a specific disease or risk factor early.
• Applies specific tests or assessments (e.g., blood pressure, mammograms).
• Can be mass screenings or selective screenings for high-risk individuals.
• Aims for timely intervention and management.

Survey

• Gathers information on health behaviours, conditions, or opinions within a population.
• Uses structured questionnaires or interviews.
• Can be cross-sectional (single point in time) or longitudinal (over a period).
• Collects self-reported information, including health behaviors and demographics.

Data Collected

• Includes information on disease incidence, prevalence, and other health indicators.
• Collects information from routine reporting, various sources (hospitals, labs, health records).
• Active and passive collection methods are employed.

Frequency

• Continuous and ongoing for real-time data on current events.
• Periodic for specific diseases or population-based risk factors, potentially related to routine health checks.
• Intervals depend on the research objectives and available resources.

Examples

• HIV incidence rates, influenza monitoring through national reporting systems.
• Mammograms for breast cancer detection, blood pressure measurement (hypertension).
• National Health and Nutrition Examination Survey (NHANES), Behavioral Risk Factor Surveillance System (BRFSS).

Advantages

• Provides real-time data for immediate responses, helps detect outbreaks early, informs policies and resource allocation.
• Facilitates early disease detection, potentially reducing morbidity and mortality, and can be cost effective if targeted properly.

Limitations

• Data quality may be inconsistent, resource intensive, especially with active surveillance.
• Underreporting and inaccuracies may occur, leading to missed cases and delayed detection of outbreaks.
• Risk of false positives/negatives, and risk of overdiagnosis or unnecessary interventions, important to consider resource needs if systems are not well-targeted.

Core Concepts of Epidemiological Surveillance

• Continuous health data collection.
• Analyzing and interpreting data.
• Sharing findings with stakeholders.
• Supporting evidence-based public health decisions.
• Essential for disease prevention and control.

Key Components of Epidemiological Surveillance

• Data Collection: Gathering health data from hospitals, labs, and communities (e.g., disease rates, mortality).
• Data Analysis: Using statistical and modeling tools to identify patterns and detect outbreaks.
• Interpretation: Understanding trends to inform public health actions.
• Dissemination: Sharing results with stakeholders to facilitate informed decision-making.

Usefulness of Surveillance

• Enables early outbreak detection, tracks disease trends, and evaluates control measures.

Understanding Active Surveillance

• Involves direct public health actions, like field investigations and healthcare visits.
• Provides accurate, real-time data for immediate responses, but requires significant resources.

Passive Surveillance Systems

• Relies on routine and voluntary reporting from healthcare providers.
• Cost-effective, but may miss cases and delay outbreak detection, easily integrates with existing systems.

Data Collection Methodologies

• Sources: hospital records, lab tests, community reports, mortality data.
• Focus: disease incidence, prevalence, demographics, and geographic patterns.

Advanced Data Analysis Techniques

• Tools: statistical models, trend analysis, and anomaly detection.
• Methods: spatial, temporal, and predictive analyses to assess risks and trends.

Interpretation of Surveillance Data

• Analyzes trends and risks to guide public health decisions.
• Supports outbreak evaluation, resource planning, and policy recommendations.

Modern Digital Surveillance Technologies

• Includes real-time monitoring, mobile apps, cloud storage, and automated alerts.
• Enhances data sharing through digital reporting and interconnected networks.

Syndromic Surveillance

• Tracks symptom patterns and healthcare usage for early outbreak warnings.
• Uses emergency data and community health indicators for rapid responses.

Wastewater Surveillance Systems

• Detects pathogens in wastewater to monitor health trends and outbreaks.
• Useful for public health planning.

Genomic Surveillance Applications

• Uses genome sequencing to track variants, mutations, and transmission.
• Helps monitor vaccine effectiveness and global pathogen trends.

Surveillance System Quality

• Key qualities: sensitivity, specificity, timeliness, simplicity, and flexibility.
• Measures system reliability and acceptability.

Screening: Active and Passive

• Active: Initiated by health authorities, offers wider coverage but needs more resources.
• Passive: Relies on individuals seeking care, with limited reach.

Active Survey Methodologies

• Engages participants directly, ensuring high-quality data but requiring more resources.
• Focuses on quality control, optimized response rates, and validation.

Ethical Considerations

• Prioritizes privacy, security, and informed consent.
• Balances public health benefits with individual rights