Immunization, Vaccines and Biologicals

Public health surveillance

An ongoing, systematic collection, analysis and interpretation of health-related data essential to the planning, implementation, and evaluation of public health practice

Surveillance is undertaken to inform disease prevention and control measures

Why is surveillance needed?

  • serve as an early warning system, identify public health emergencies
  • guide public health policy and strategies
  • document impact of an intervention or progress towards specified public health targets/goals
  • understand/monitor the epidemiology of a condition to set priorities and guide public health policy and strategies

An effective surveillance system has the following functions:

  • detection and notification of health events
  • collection and consolidation of pertinent data
  • investigation and confirmation (epidemiological, clinical and/or laboratory) of cases or outbreaks
  • routine analysis and creation of reports
  • feedback of information to those providing the data
  • feed-forward (i.e. the forwarding of data to more central levels)
  • reporting data to the next administrative level

Why surveillance for vaccine-preventable diseases?

The same issues also apply to surveillance related to vaccine-preventable diseases. Hence, surveillance - as well as coverage and impact monitoring - is an important and integral component of any immunization program. In many countries, detailed data on vaccine-preventable dieases are collected, analysed and fedback in the program, to guide activities

Surveillance is especially important to monitor progress for programs that aim at specific goals, for example polio eradication, measles control or elimination, and maternal and neonatal tetanus elimination. The "AFP surveillance" systems that have been set up in many countries can be used as backbone to immunization-related surveillance for other diseases

Surveillance networks have also been established to provide support to surveillance sites for specific diseases

Laboratory confirmation is important for certain vaccine-preventable diseases, including polio and measles. For these diseases, a global laboratory network has been established, taking advantage of the specific capacities of the laboratories in the network

WHO provides recommended standards for surveillance of vaccine-preventable diseases, and makes data available in a consolidated format