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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

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

11. 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

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

13. 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

14. 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

15. 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

16. Serotype Distribution, 2006 & 2007
Children < 5 years

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

18. If you would like to discuss your state’s data
contact Kristin Brown
by phone (404) or by