PEDIATRICS Vol. 107 No. 4 April 2001, pp. 755-758

SPECIAL ARTICLE:
Impact of the Joint Statement by the American Academy of Pediatrics/US Public Health Service on Thimerosal in Vaccines on Hospital Infant Hepatitis B Vaccination Practices

Marjorie B. Hurie, RN, MS^*, Thomas N. Saari, MD^{, §}, and Jeffrey P. Davis, MD^*,

From the ^* Bureau of Communicable Diseases, Wisconsin Division of Public Health, Madison, Wisconsin; the  Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Wisconsin, Madison, Wisconsin; the ^§ Immunization and Infectious Diseases Committee, Wisconsin Chapter of the American Academy of Pediatrics, Madison, Wisconsin; and the  Departments of Pediatrics and Preventive Medicine, University of Wisconsin, Madison, Madison, Wisconsin.

	ABSTRACT

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Objective.  To determine the impact of the American Academy of Pediatrics/US Public Health Service (AAP/USPHS) joint statement on thimerosal in vaccines on hospital infant hepatitis B vaccination policies in Wisconsin.

Methods.  The nurse managers of hospital newborn nurseries (n = 110) were surveyed by mail. Nonresponders were resurveyed. Twelve hospitals no longer provided obstetric services. Of the remaining 98 hospitals, 84 (86%) responded to the initial mailing and 14 (14%) responded to the second mailing. The number of hospitals that offered hepatitis B vaccine to infants before July 1999 was compared with that in March 2000. The number of hospitals that had policies in place to vaccinate infants whose mothers' hepatitis B surface antigen status (HBsAg) was positive or unknown during the thimerosal alert (July 1999 through November 1999) was compared with that in March 2000.

Results.  Before July 1999, 81% of the hospitals representing 84% of reported Wisconsin births routinely offered hepatitis B vaccine to all infants. By March 2000, 50% of hospitals, representing 43% of births, had resumed routine infant hepatitis B vaccination. Physician decision to use a combination Haemophilus influenzae type b hepatitis B vaccine was the most frequently given reason for not reinstituting infant hepatitis B vaccination. During the thimerosal alert, 23% of hospitals did not have policies to vaccinate infants whose mothers were HBsAg-positive and 51% did not have policies to vaccinate infants whose mothers' HBsAg status was unknown. By March 2000, 6% of hospitals still did not have policies to vaccinate infants whose mothers were HBsAg-positive and 24% did not have policies to vaccinate infants whose mothers' HBsAg status was unknown.

Conclusion.  The AAP/USPHS joint statement on thimerosal in vaccines has resulted in a 38% decrease in the number of hospitals routinely offering infants hepatitis B vaccine. Although thimerosal-free hepatitis B vaccine is now available, some hospitals still do not have appropriate policies in place for vaccinating infants whose mothers' HBsAg status is positive or unknown. In the future, policymakers should include anticipated consequences that may result from changes in immunization policy in their recommendations.  Key words:  hepatitis B vaccine, infant, thimerosal, hospital.

Nearly a decade ago, the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) recommended that all infants receive hepatitis B vaccine, preferably at birth.^1-3 By 1995, 65% of hospitals in Wisconsin and 47% of hospitals nationwide were reported to be administering the first dose of hepatitis B vaccine to infants before hospital discharge.^4,5 This practice halted abruptly in July 1999 when the AAP and the US Public Health Service (USPHS) issued a joint statement on thimerosal in vaccines suggesting that hepatitis B vaccination of infants born to hepatitis B surface antigen (HBsAg)-negative women be postponed from birth until 2 to 6 months of age.⁶ The suggestion was made in response to concerns about the presence of thimerosal in some vaccines including both manufacturers' hepatitis B vaccines. Thimerosal is a derivative of ethyl mercury and has been used as an additive to vaccines to preventing bacterial contamination. A Food and Drug Administration review of all mercury-containing foods and drugs determined that some children could be exposed to a cumulative level of mercury during the first 6 months of life that exceeds one of the federal guidelines on methyl mercury. The AAP/USPHS joint statement noted that because of the substantial risk of disease, there was no change in the hepatitis B vaccination recommendations for infants whose mothers' HBsAg status was positive or unknown.⁶

A preservative-free hepatitis B vaccine became available in September 1999 and the ACIP and the AAP advised providers and hospitals to resume their infant hepatitis B vaccination programs.^7,8 In November 1999, the Wisconsin Immunization Program and the Wisconsin Council on Immunization Practices sent a joint letter to the chiefs of pediatrics, family practice and obstetrics, and infection control practitioners announcing the availability of preservative-free hepatitis B vaccine and urging hospitals to resume infant hepatitis B vaccination. We report here the results of a survey of birthing hospitals to determine the extent to which hospital infant hepatitis B vaccination policies have changed in response to the thimerosal concern.

	METHODS

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A questionnaire was mailed in February 2000 to the nursery nurse managers in the 110 hospitals that had participated in our previous survey.⁴ A second mailing was sent to nonresponders in April 2000. The questionnaire was self-administered and completed by the nurse manager. It requested information on what the hospital's infant hepatitis B vaccination practice had been during 3 time periods: before July 1999, from July 1999 to November 1999 (a period of time we defined as the thimerosal alert), and in March 2000. Specifically, the questionnaire asked whether it was hospital policy or practice to give hepatitis B vaccine to an infant whose mother was known to be HBsAg-positive, an infant whose mothers' HBsAg status was unknown, or an infant whose mothers' HBsAg status was known to be negative during the 2 latter time periods. The questionnaire also asked the respondent to estimate the number of infants who had received hepatitis B vaccine during the 2 to 3 months before March 2000 and invited open-ended comments on any aspect of the infant hepatitis B vaccination program. The Bureau of Health Information provided the number of births at each hospital during 1998, the most recent year for which information was available.⁹ The total births cited here (63 301) is less than the total 1998 Wisconsin births (66 687) because some hospitals that reported births in 1998 closed during 1998 and thus were not included in our survey.

	RESULTS

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Of the 110 birthing hospitals, 12 no longer provided obstetric services and were eliminated from the analysis. Staff in all of the remaining 98 hospitals responded to the survey: 84 (86%) responded to the initial mailing and 14 (14%) responded to the second mailing.

Before July 1999, hepatitis B vaccine was being routinely offered to infants born in 79 (81%) Wisconsin hospitals, representing 84% (53 186) of the 63 301 births in 1998 among hospitals that were still providing obstetric services in 1999. During the thimerosal alert, 71 (90%) of these hospitals discontinued routine infant hepatitis B immunization. By March 2000, 49 (50%) hospitals, representing 43% (27 477) of births were again routinely offering infants hepatitis B vaccine. Respondents estimated that the mean percentage of infants receiving hepatitis B vaccines from these hospitals during the past 2 to 3 months was 86%. The mean estimated percentage of infants receiving vaccine from hospitals that were not routinely offering hepatitis B vaccine was 8%. The most frequently mentioned reasons for not reinstituting routine infant vaccination were physician decision to begin using a combination Haemophilus influenzae type b hepatitis B vaccine (which cannot be given before 6 weeks of age), physician decision to begin the vaccine series in the office, and parents' lack of insurance coverage for the vaccine.

The percent decrease in the number of hospitals routinely offering hepatitis B vaccine to infants in March 2000 compared with that before July 1999 varied by public health region and ranged from 11% in the southern region to 72% in the southeastern region (Table 1).

During the thimerosal alert, 23% of hospitals did not have policies to vaccinate infants whose mothers were HBsAg-positive and 51% did not have policies to vaccinate infants whose mothers' HBsAg status was unknown (Table 2). By March 2000, 6% of hospitals still did not have policies to vaccinate infants whose mothers were HBsAg-positive and 24% did not have policies to vaccinate infants whose mothers' HBsAg status was unknown.

The 6 hospitals that did not have policies in March 2000 to vaccinate infants whose mothers were HBsAg-positive were all located in the same public health region and had 270 or fewer births per year. The Wisconsin Perinatal hepatitis B Prevention Program received reports of births to 4 HBsAg-positive women in 2 of these hospitals before July 1999. A review of these infants' vaccine histories indicated that all 4 infants received hepatitis B immune globulin and hepatitis B vaccine appropriately.

	DISCUSSION

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Between July 1999 and March 2000, there was a 38% decline in the number of hospitals offering routine infant hepatitis B vaccination and a 48% decline in the number of newborn infants routinely being offered vaccine. According to the Recommended Childhood Immunization Schedule,¹⁰ the age range for the first dose of hepatitis B vaccine is from birth to 2 months of age. However, giving the vaccine at birth provides a safety net for infants whose mothers' positive HBsAg test result may not have been communicated correctly to the hospital. A Michigan infant, whose mother was known to be HBsAg-positive by her obstetrician, recently died of acute hepatitis B virus (HBV) infection. The mothers' HBsAg test result had been communicated inaccurately to the hospital and the hospital had stopped routinely vaccinating infants because of concerns about thimerosal.¹¹ When given at birth, hepatitis B vaccine alone has been shown to be 88% effective in preventing perinatal HBV transmission.¹² In addition to protecting infants from exposure to HBV perinatally, giving hepatitis B vaccine at birth has been shown to increase the likelihood that infants will complete the 3-dose hepatitis B vaccine series.¹³

This study is limited by the unconfirmed self-reports from hospitals and the lack of 1999 Wisconsin birth data. However, it is unlikely that there will be a substantive difference between 1998 and 1999 births. Preliminary data on in-state resident births show that there were only ~700 fewer births in 1999 compared with 1998. There were also occasional discrepancies between official hospital policy and actual practice. Specifically, the decline in hospital infant hepatitis B vaccination coverage between July 1999 and March 2000 may be slightly less than the data suggest. In 3 instances, 40% to 90% of infants were being vaccinated in hospitals that did not have policies to vaccinate all infants because physicians ordered the vaccine individually. Approximately 1250 births occurred in these hospitals during 1998.

The most frequently mentioned reason for deciding not to reinstitute routine infant hepatitis B vaccination in the nursery was the intent to give combination H influenzae type b hepatitis B vaccine later in infancy. However, the decision to give hepatitis B vaccine at birth and a combination vaccine later need not be mutually exclusive. The ACIP, the AAP, and the AAFP have stated that "an extra dose of Hib or Hep B vaccine may be administered as part of a combination vaccine to complete a vaccination series for another component of the combination."¹⁴ Another reason respondents gave for not reinstituting routine infant hepatitis B vaccination was parents' lack of insurance coverage for the vaccine. However, hospitals can control vaccine costs by enrolling in the Vaccines for Children program through the state immunization program. The Vaccines for Children program provides federally purchased vaccine free of charge for children who are on Medicaid, uninsured, or are Native American.

The southeastern public health region, where the highest percentage of hospitals discontinued routine infant hepatitis B vaccination programs, includes Milwaukee County and is the most populous region in the state. This is the region where 71 (36%) of the HBsAg-positive pregnant women identified in Wisconsin in 1999 resided. Because hospitals in this region are more likely to have births to HBsAg-positive women, it is particularly important that these hospitals resume routine infant hepatitis B vaccination.

Also worrisome is the number of hospitals that did not have a hospital policy to give hepatitis B vaccine to infants whose mothers' HBsAg status was positive or unknown during the thimerosal alert. Although the AAP/USPHS joint statement noted that the suggestion to defer routine infant hepatitis B vaccination did not apply to infants whose mothers' HBsAg status was positive or unknown, more than half of the hospitals apparently overlooked this important exception. Even after preservative-free hepatitis B vaccine had been available for 6 months, 6 hospitals did not have a policy to vaccinate infants whose mothers' HBsAg status was positive and almost a quarter of the hospitals did not have a policy to vaccinate infants whose mothers' HBsAg status was unknown. The infants who were born to HBsAg-positive mothers in 2 of these hospitals were appropriately treated because individual physicians were aware of and followed post-HBV exposure treatment guidelines. However, these guidelines apparently have not been instituted as hospital policy and the nursery nurse managers appear unaware of the need for such policies. Even hospitals that have never admitted a parturient woman whose HBsAg status was positive or unknown should still have appropriate policies to prevent perinatal HBV transmission in place.¹⁵ Model labor and delivery unit and nursery unit guidelines to prevent HBV transmission that have been reviewed for technical accuracy by Centers for Disease Control and Prevention are available from the Immunization Action Coalition at www.immunize.org.

	FOOTNOTES

Reprints requests to (M.B.H.) Wisconsin Division of Public Health, Immunization Program, Box 2659, 1 W Wilson St, Madison, WI 53701-2659.

Received for publication Oct 30, 2000; accepted Jan 24, 2001.

	ABBREVIATIONS

ACIP, Advisory Committee on Immunization Practices; AAP, American Academy of Pediatrics; AAFP, American Academy of Family Physicians; USPHS, US Public Health Service; HBsAg, hepatitis B surface antigen.

	REFERENCES

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1. Centers for Disease Control and Prevention. Hepatitis B virus: a comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR Morb Mortal Wkly Rep. 1991;40(No. RR-13):1-25
2. American Academy of Pediatrics, Committee on Infectious Diseases Universal hepatitis B immunization. Pediatrics 1992; 89:795-800 [Abstract/Free Full Text]
3. American Academy of Family Physicians. Recommendations for Hepatitis B Preexposure Vaccination and Postexposure Prophylaxis. Kansas City, MO: American Academy of Family Physicians; 1992:1-20. AAFP Publ. No. 966
4. Hurie MB, Saari TN, Proctor ME, Davis JP Hospitals' responses to universal infant hepatitis B vaccination recommendations. Pediatrics 1995; 96:875-879 [Abstract/Free Full Text]
5. Kim SC, Sinai LN, Casey R, Pinto-Martin JA Universal hepatitis B immunization. Pediatrics 1995; 95:764-766 [Abstract/Free Full Text]
6. Centers for Disease Control and Prevention Notice to readers: thimerosal in vaccines: a joint statement of the American Academy of Pediatrics and the Public Health Service. MMWR Morb Mortal Wkly Rep 1999; 48:563-565 [Medline]
7. Centers for Disease Control and Prevention Notice to readers: availability of hepatitis B vaccine that does not contain thimerosal as a preservative. MMWR Morb Mortal Wkly Rep 1999; 46:780-782
8. Rennels MB Reinstitute hepatitis B vaccine for all infants. AAP News 1999; 15:6 [Abstract/Free Full Text]
9. Bureau of Health Information, Division of Health Care Financing, Department of Health and Family Services. Wisconsin Births and Infant Deaths 1998. Available from: URL:http://www.dhfs.state.wi.us/births/98birth.pdf
10. Centers for Disease Control and Prevention. Notice to readers: recommended Childhood Immunization ScheduleUnited States, 2000. MMWR Morb Mortal Wkly Rep. 2000;49:35-38, 47
11. Three-month-old baby dies of acute hepatitis B. Michigan Immunization Update. 2000;7:1-2
12. Xu ZY, Liu CB, Francis DP, Prevention of perinatal acquisition of hepatitis B virus carriage using vaccine: preliminary report of a randomized, double-blind placebo-controlled and comparative trial. Pediatrics 1985; 76:713-718 [Abstract/Free Full Text]
13. Yusuf HR, Daniels D, Smith P, Coronado V, Rodewald L Association between administration of hepatitis B vaccine at birth and completion of the hepatitis B and 4:3:1:3 vaccine series. JAMA 2000; 284:978-983 [Abstract/Free Full Text]
14. Centers for Disease Control and Prevention. Combination vaccines for childhood immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP). MMWR Morb Mortal Wkly Rep. 1999;48(No. RR-5):1-15
15. Centers for Disease Control and Prevention. Protection against viral hepatitis: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR Morb Mortal Wkly Rep. 1990;39(No. RR 2): 17-19