VPD Surveillance Manual, 5th Edition, 2011 Enhancing Surveillance: Chapter 19-119 Chapter 19: Enhancing Surveillance

Surveillance activities are critical to detecting vaccine-preventable diseases and gaining information to help control or address a problem. However, complete and accurate reporting of cases is dependent on many factors, such as reporting source, timeliness of investigation, and completeness of data. In addition, various methods for conducting surveillance are used to collect information, depending on disease incidence, specificity of clinical presentation, available laboratory testing, control strategies, public health goals, and stage of vaccination program. For vaccine-preventable diseases, passive surveillance is the most common method, although active surveillance may be needed in special surveillance situations. Active surveillance is often short-term and usually requires more funding than passive surveillance. Common systems used for disease surveillance include national notifiable disease reporting; physician, hospital, or laboratory-based sentinel surveillance, and population-based surveillance.1 Sentinel surveillance involves a limited number of recruited participants, such as healthcare providers or hospitals, that report specified health events that may be generalizable to the whole population.2 The National Notifiable Diseases Surveillance System (NNDSS)3 is the passive surveillanc