1. Reductions in Hepatitis B Vaccine Coverage for Infants Born to Women With Unknown Hepatitis B Surface Antigen (HBsAg) Status: Oregon

2. Background
Risk of perinatal HBV infection among infants born to HBsAg+ mothers is 10-85%
Perinatally-infected infants:
90% risk of chronic infection
25% will die of chronic liver disease
>90% of these infections preventable

3. The Theoretical Risk of Thimerosal in Vaccines, 1999
Finding that infants were being exposed to levels of mercury from vaccines exceeding the EPA guidelines raised concern
The amount did not exceed ATSDR, FDA, or WHO guidelines

4. On July 7, 1999, the PHS and the AAP recommended that the birth dose of HBV be postponed until 2-6 months of age, unless the mother’s HBsAg status was positive or unknown

5. In Sept. 1999, the CDC announced that thimerosal-free HBV was available, and recommended that the policy to vaccinate all newborns at birth be reinstated
Sept. 1999
CDC announced
Thimerosal-free
HBV available
July 7, 1999
PHS/AAP
statement

6. By Dec. 1999, thimerosal-free HBV was available in all states
Sept. 1999
CDC announced
Thimerosal-free
HBV available
Dec. 1999
Thimerosal-free
HBV available
in all states.
July 7, 1999
PHS/AAP
statement

7. What effect did these changes in recommendations have on infants born to mothers whose HBsAg status was unknown at the time of delivery?

8. Methods Oregon’s electronic birth certificate (EBC) registry:
Implemented in 1998
Core demographic variables
Collects additional data on maternal HBsAg status and whether the infant was immunized or received HBIG at birth

9. Methods
Previous studies showed that not all the hospitals collect the additional data
Limited our reviews to hospitals that reported maternal status as unknown for 25% or fewer of their births

10. April-June 1999 August-October 1999 April-June 2000
We identified all infants born to HBsAg unknown mothers by reviewing EBC data for the periods of:
April-June 1999
(Pre- PHS/AAP statement)
August-October 1999
(Post- PHS/AAP statement)
April-June 2000
(Thimerosal-free vaccine available)

11. We reviewed charts: Maternal: Race/ethnicity Age Prenatal care
Medical insurance
HBsAg testing
Infant
Gestational Age
Birthweight
Apgar score
Administration of HBV or HBIG

12. Reviewed charts at 34 (64%) of the 53 Oregon hospitals
This represented 49% of the births in Oregon during the time periods studied

13. 298 Mother-infant pairs where mother’s status was unknown at delivery
16,515 births at 34 Hospitals
1138 mothers identified as unknown on EBC
308 HBsAg unknown mothers
(1.9% of the births)
10 had insufficient information
298 Mother-infant pairs where mother’s status was unknown at delivery

14. Of these 298, the mothers’ HBsAg status was still unknown at the time of discharge for 147 (49%)

15. HBsAg status unknown mothers
Prenatal Care
HBsAg status unknown mothers
(n=147)
OR 2000 EBC

16. HBsAg status unknown mothers
Medical Insurance
HBsAg status unknown mothers
(n=147)
OR 2000 EBC

17. Infant Demographics

18. Vaccination Status (n=147)

19. % of Hospitals With Policy to Give HBV to All Newborns Before Discharge (n=53)

20. Limitations Hospitals not randomly chosen
No reason to believe that the hospitals not collecting these data had better HBV immunization rates

21. Conclusions
HB vaccination coverage of infants born to unscreened women plummeted following the July 1999 announcement
Coverage remained significantly lower months later, despite recommendations that these infants continue to be immunized

22. Conclusions
Infants born to unscreened mothers were rarely immunized within 12 hours of birth, regardless of time period

23. Recommendations
When changes are made in established vaccination practices, policy makers need to make strenuous efforts to ensure that such changes are not misinterpreted, resulting in failure to immunize appropriate groups

24. Recommendations
Our findings underscore the importance of recent ACIP recommendations encouraging routine use of hepatitis B vaccine before hospital discharge

25. Acknowledgements Oregon Health Services Holly Corwith Paul Cieslak
Hepatitis Branch, CDC
Anthony Fiore
Harold Margolis