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VPD
Surveillance
Surveillance is the …
Ongoing systematic collection,
collation, and analysis of health data
and the dissemination of that
information to those who need to know
so appropriate action can be taken
Surveillance is the continued vigil over the
occurrence and distribution of disease and
conditions which increase the risk
of disease transmission
Surveillance is information for action
A surveillance system should:
•Describe each person having an infection or disease
•Determine source of infection and mode of
transmission
•Identify exposed, susceptible person to whom the
infection may have been transmitted
•Specify frequency of occurrence of infection
in different population groups
•Prepare and distribute surveillance reports
A major objective of disease
surveillance is…
To determine the extent of infections
and the risk of disease transmission
…so control measures can be applied
effectively and disease can be
prevented
Five functions of a surveillance system
•Case detection and notification
•Investigation and confirmation
•Data collection and consolidation
•Data analysis
•Information dissemination
All done to guide public health action
Additional supporting functions
of disease surveillance:
• Setting standards (e.g case definition)
• Training and supervision
• Setting up laboratory support
• Establishing communication network
• Optimizing resource management
• Improve coordination/integration
Surveillance tasks differ
depending upon the level
District level
Provincial level
Central or National level
Surveillance at the district level
• Diagnosis and case management
• Reporting of cases
• Simple tabulation and graphing of data
Surveillance at the Provincial level
• Case
management for more difficult cases
• Analyze data from peripheral level for
epidemiological links and trends
• Monitor data to check if control targets
have been met
• Investigate suspected outbreaks.
• Feed back to the district
• Report to central level
Surveillance at the National level
• overall support and coordination of national
surveillance activities.
• provision of laboratory diagnosis data
•analyze data from intermediate level for:
• epidemiological links
• trends
• achievement of control targets.
• support intermediate level for outbreak control
•feed back to intermediate level, and report to WHO
regional office
Information gathered from Disease
Surveillance can be used to…
• Estimate the magnitude of health problem
• Determine geographic distribution
• Portray natural history of a disease
• Detect epidemics
• Monitor changes in infectious agents
• Evaluate control measures
• Facilitate and improve planning
• Generate hypothesis and stimulate research
Sources of data for surveillance
• Notifiable disease reports
• Laboratory results
• Vital records
• Sentinel surveillance
• Birth/death registries
• Surveys
•Vaccine utilization records
• Vaccine adverse event reporting system
Types of surveillance
Passive surveillance: data are routinely collected and forwarded
to more central levels
Active surveillance: data are sought out by visiting or contacting
a reporting site
Comprehensive surveillance: data are collected from numerous
sites throughout a country in order to
achieve representation of whole population
Sentinel surveillance: selected sites report data, can be used to
monitor trends and collect detailed information, but may not
represent the entire country
Community-based, facility-based and laboratory-based
surveillance: involve detection and notification by communities,
health facilities and laboratories
Prioritize which diseases need
surveillance, diseases:
• does the disease result in a high disease impact? (morbidity,
mortality, disability)
• does the disease have a significant epidemic potential
(cholera, measles)
• is the disease a specific target of a national / international
control program
• will the collected information lead to significant public
health action?
What needs to be addressed for each disease
under surveillance?
•The case definition should be
•Clear
• Appropriate
• Consistent throughout the surveillance system
• The reporting mechanism should be
• Clear
• Efficient
• Appropriate reporting periodicity
• Available to all relevant persons
•The analysis of data should be
• Appropriate
• Allow for proper presentation
• Used for decision-making
• The people doing the surveillance should
• Have a good understanding of the value of surveillance
system
• Understand their surveillance task
• Have sufficient resources
• The personnel involved should receive appropriate
• Training
• Supervision
• The feed-back from central levels should be
• Appropriate in format
• Sufficient and frequent enough
• Motivating
The surveillance partners
immunization
program staff
lab staff
epidemiologists
Pediatrician / PPA
mass media
private
sector
(informal health care
providers)
NGO sector
agencies &
institutions
LHWs
Community
National
Manager EPI
WHO
Sr. MO
NS Cell
LAB
Provincial
ERC
WHO
Medical
Officer
Provincial
Manager EPI
Courier
Province
National
AFP Surveillance System - Pakistan
District
Stool specimens
from AFP cases
DSC/SO
EDO(H)
DC
LHWs in community
THs/DHQ/THQ/RHCs/BHUs
Pediatricians/Clinician
Private sector
Thank you