What is Global Influenza Surveillance?
Global influenza surveillance is a comprehensive and coordinated effort to monitor and track the spread of influenza viruses across the world. This system is vital for identifying new strains of the virus, understanding their epidemiological characteristics, and guiding public health interventions.
Objectives of Influenza Surveillance
The main objectives of global influenza surveillance are to:
1. Detect and monitor influenza activity worldwide.
2. Identify and characterize circulating influenza viruses.
3. Provide data for vaccine strain selection.
4. Assess the impact of influenza on public health.
5. Guide public health interventions and policies.Components of the Surveillance System
The global influenza surveillance system is composed of several key components:1. National Influenza Centers (NICs): These serve as the backbone of the GISRS, collecting and analyzing influenza specimens from various sources within their countries.
2. WHO Collaborating Centers (CCs): These centers provide advanced virological and epidemiological support to NICs, including virus characterization and the development of reference reagents.
3. Essential Regulatory Laboratories (ERLs): These laboratories are involved in the regulatory aspects of vaccine strain selection and production.
4. Reference Laboratories: These provide specialized testing and support for the identification of novel or rare influenza viruses.
Data Collection and Sharing
Data collection in global influenza surveillance involves the systematic gathering of information on influenza-like illness (ILI) and severe acute respiratory infections (SARI) from sentinel sites. These data are then shared through platforms like the
FluNet and
FluID databases, which are accessible to public health officials and researchers worldwide.
Vaccine Strain Selection
One of the critical functions of global influenza surveillance is to inform the selection of strains for the seasonal influenza vaccine. Twice a year, WHO convenes the
Vaccine Composition Meeting, where experts review surveillance data to recommend the strains to be included in the upcoming influenza season's vaccine.
Challenges in Global Influenza Surveillance
Despite its importance, global influenza surveillance faces several challenges:
1. Variability in Surveillance Capacity: Differences in resources and infrastructure among countries can lead to inconsistent data quality.
2. Emerging Influenza Strains: The constant evolution of influenza viruses poses a challenge for timely detection and response.
3. Data Sharing and Coordination: Ensuring timely and transparent data sharing among countries and organizations can be difficult.
4. Resource Constraints: Limited funding and resources can impede the effectiveness of surveillance activities.The Role of Epidemiology
Epidemiology plays a crucial role in global influenza surveillance by:
1. Analyzing Trends: Epidemiologists analyze data to identify trends in influenza activity and the spread of different strains.
2. Risk Assessment: They assess the risk posed by emerging influenza strains to guide public health responses.
3. Policy Development: Epidemiological data inform the development of policies and guidelines for influenza prevention and control.
4. Research: Epidemiologists conduct research to understand the transmission dynamics and impact of influenza on populations.Conclusion
Global influenza surveillance is a vital component of public health efforts to combat influenza. Through the coordinated efforts of the WHO and its partners, the system provides valuable data for vaccine development, risk assessment, and public health interventions. While challenges remain, continual advancements in epidemiological methods and international collaboration are essential for improving the effectiveness of influenza surveillance worldwide.
