Which statement best describes active surveillance compared to passive surveillance?

• A. Active surveillance relies on providers submitting reports to public health on their own.
• B. Active surveillance involves public health authorities actively seeking cases.
• C. Active surveillance uses only laboratory results.
• D. Active surveillance is only used for outbreak investigations.

Answer: (B)

Active surveillance means public health authorities take the initiative to find cases, rather than waiting for reports to come in. They actively seek out information by reviewing multiple data sources—lab results, hospital records, physician reports, and other data feeds—and may directly contact providers or facilities to identify cases. This proactive approach helps detect cases sooner, reduces underreporting, and provides more complete and timely data for monitoring trends and guiding interventions.

In contrast, passive surveillance relies on healthcare providers or laboratories to report cases on their own, which can miss cases or cause delays. Active surveillance is not limited to lab data and is not restricted to outbreak investigations; it is used for ongoing monitoring and targeted surveillance as well.