Using Surveillance Indicators for Vaccine-Preventable Diseases (VPDs): National Notifiable Diseases Surveillance System (NNDSS), 2003-2013

BACKGROUND:   The National Notifiable Diseases Surveillance System (NNDSS) supports assessment of epidemiologic trends and programmatic impact. NNDSS data are used by states/jurisdictions and are transmitted to CDC through the National Electronic Telecommunications System for Surveillance (NETSS) or the National Electronic Disease Surveillance System (NEDSS). Variations in reporting/notification may be due to disease/condition characteristics (e.g., symptoms, severity), availability of laboratory diagnostics, patient/provider awareness, jurisdiction attributes (e.g., laws, regulations), disease transmission setting, and capacity for electronic data exchange. Surveillance indicators can assess infrastructure, practices/procedures, thoroughness/appropriateness of case investigation, laboratory performance, and completeness of case reporting.

METHODS:  Analyses used NNDSS data from MMWR  (2003-2013). Specific indicators included overall completeness of epidemiologically important information, timeliness of reporting and notification, appropriateness and completeness of laboratory testing, completeness of vaccination history, and importation status.

RESULTS:  Final NNDSS data suggest that annually, for H. influenzae, the percent of cases <5 years with serotype testing was 40-63% (range by year) and with complete vaccine history was 15-23%. For measles, overall completeness of data was 48-79%, importation status was known for 18-73% of cases, and laboratory testing was done at CDC for 24-70% of cases. For pertussis, 17-37% of children <7 years had complete vaccine history. For rubella, pregnancy status was known for 40-100% of cases and importation status was known for 0-75% of cases. For mumps, overall data completeness was 40-60%.

CONCLUSIONS:   Surveillance indicators can assess the quality of the national electronic surveillance data.  Although these indicators may not accurately reflect state-based data or surveillance effort in certain situations, they can identify components of surveillance and electronic data exchange that need improvement.