Improving Haemophilus influenzae Serotype Reporting Kristin Brown, MPH March 19, 2008

Haemophilus influenzae (Hi) Serotypes Six capsular serotypes: a, b, c, d, e, & f H. influenzae type b (Hib) caused 95% of all invasive disease in the pre vaccine era Hib was leading cause of bacterial meningitis and other serious invasive diseases among children <5 years Hib vaccine introduced for infants in 1988 and recommended in 1991

National Hi Surveillance Invasive Hib is a nationally notifiable disease Invasive Hib in children < 5 years reportable in all states Reporting for other ages vary from state to state Reporting of invasive non-type B disease also varies States report cases weekly to the National Notifiable Diseases Surveillance System (NNDSS) All states report “core” demographic data Most states report “extended” epidemiologic data

Why do we care about the serotype? Locally Determine appropriate public health response Detect clusters or changes in local epidemiology Nationally Detect changes in Hib incidence or epidemiology Evaluate and inform Hib vaccine policy

What was wrong with the national Hi serotype data? Serotype distribution in children < 5 years There wasn’t very much of it Serotype was reported for only 30% of cases in children < 5 years 204 of 293 cases were reported as unknown or not tested or had no serotype data reported Reporting of serotype declining over the past few years N = 293 *Includes cases with serotype unknown/not typed and cases with no data for serotype

Hi Serotype Reporting: 2006 Provisional vs. Past Years Children < 5 years only 1994 – provisional 2006, NNDSS Past years include additional data collected through other mechanisms

Project Goals Improve national serotype data so national surveillance could be used to detect changes in Hib incidence in children < 5 years of age Specific tasks were identified Determine what additional serotype data was available to supplement NNDSS serotype data Determine why the proportion of cases with reported serotype were decreasing in national surveillance systems

Methods Assessed data quality for each state Abrupt changes Patterns across states Consist data quality Prioritized states for follow-up No serotype data System-related data problems States for which there was no other source of serotype data

Methods Contacted state health departments Referred system problems to National Center for Public Health Informatics (NCPHI) Collected information from additional sources Active Bacterial Core Surveillance (ABCs) Data sent from states who were not able to correct data in NNDSS prior to closing

Most common problem with serotype data Abrupt loss of data Similar data changes across states Percent with Serotype reported Cases reported to NNDSS

Hi Serotype Reporting Problems: Incorrect mapping of data from NEDSS to NETSS No extended Hi data Serotypes other than B becoming ‘unknown’ States began using new systems Some were not set up to transmit extended Hi data to NETSS Serotype more difficult to enter into newer systems and or could be entered into different fields

Serotype reporting for case in children < 5 years, 2006 Cases reported to the National Notifiable Diseases Surveillance System (NNDSS) and additional serotype data

Serotype of Reported Hi in children < 5 years, 1994-2006 Number of cases Year Cases reported to the National Notifiable Diseases Surveillance System (NNDSS) and additional serotype data

Strategies to Improve Serotype Data Increase communication between CDC and states Direct access for the CDC program to NEDSS data Efforts underway to get direct access to NEDSS data HL7 messages for Hi planned for 2008 so states can begin sending data to NEDSS Supplementing NNDSS surveillance data with data from other sources

Serotype of Reported Hi in children < 5 years, 1994-2007 provisional Number of cases Year Cases reported to the National Notifiable Diseases Surveillance System (NNDSS) and additional serotype data

Serotype Distribution, 2006 & 2007 Children < 5 years

Acknowledgements State Health Departments Active Bacterial Core Surveillance sites CDC Colleagues Ben Silk Kim Cushing Pam Srivastava Sandra Roush Fatima Coronado

If you would like to discuss your state’s data contact Kristin Brown by phone (404) 639-6247 or by email khbrown@cdc.gov