ELECTRONIC ARTICLE |
From the New Hampshire Department of Health and Human Services, Division of Public Health Services, Concord, New Hampshire
| ABSTRACT |
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Methods. Data were extracted from 2021 paired mother-infant records for the year 2000 birth cohort in New Hampshire's 25 delivery hospitals. Assessment was done on the following: prenatal screening for hepatitis B and rubella, administration of the hepatitis B vaccine birth dose to all infants, administration of hepatitis B immune globulin to infants who were born to hepatitis B surface antigen-positive mothers, rubella immunity, and administration of in-hospital postpartum rubella vaccine to rubella nonimmune women.
Results. Prenatal screening rates for hepatitis B (98.8%) and rubella (99.4%) were high. Hepatitis B vaccine birth dose was administered to 76.2% of all infants. All infants who were born to hepatitis B surface antigen-positive mothers also received hepatitis B immune globulin. Multivariate logistic regression showed that the month of delivery and infant birth weight were independent predictors of hepatitis B vaccination. The proportion of infants who were vaccinated in January and February 2000 (48.5% and 67.5%, respectively) was less than any other months, whereas the proportion who were vaccinated in December 2000 (88.2%) was the highest. Women who were born between 1971 and 1975 had the highest rate of rubella nonimmunity (9.5%). In-hospital postpartum rubella vaccine administration was documented for 75.6% of nonimmune women.
Conclusion. This study documents good compliance in New Hampshire's birthing hospitals with national guidelines for perinatal hepatitis B and rubella prevention and highlights potential areas for improvement.
Key Words: hepatitis B vaccine hepatitis B surface antigen rubella rubella vaccine postpartum congenital rubella syndrome
Abbreviations: HBV, hepatitis B virus ACIP, Advisory Committee on Immunization Practices AAP, American Academy of Pediatrics HBsAg, hepatitis B surface antigen HBIG, hepatitis B immune globulin CRS, congenital rubella syndrome NH DHHS, New Hampshire Department of Health and Human Services CI, confidence interval
Prenatal health care providers and delivery hospitals play a crucial role in preventing vertical transmission of the hepatitis B virus (HBV) and congenital rubella infection.1 HBV infection is an established cause of both acute and chronic hepatitis, as well as cirrhosis of the liver2; transmission from a chronically infected woman to her infant accounts for
24% of chronic HBV infections in the United States.3,4 To prevent perinatal HBV infection, the Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics (AAP) recommend routine prenatal screening to identify women who carry the hepatitis B surface antigen (HBsAg); newborns who are born to such women should receive the first dose of hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth.5,6
First-trimester congenital rubella infection can result in fetal death, premature delivery, and an array of congenital abnormalities known as congenital rubella syndrome (CRS).7,8 The number of reported rubella and CRS cases in the United States has declined dramatically since licensure of rubella vaccine in 1969,9 and elimination of indigenous rubella and CRS is a national public health goal.10 However, 7.5% to 17.4% of women of childbearing age may be rubella nonimmune, and their unborn children may be at risk for CRS.11 To prevent future cases of CRS, the ACIP and American College of Obstetrics and Gynecology recommend prenatal rubella immunoglobulin G screening and postpartum vaccination of women who lack evidence of rubella immunity.7,9 To evaluate current performance on recommended perinatal hepatitis and rubella prevention practices, we conducted a statewide hospital record review of maternal and infant medical records from the year 2000 birth cohort in New Hampshire.
| METHODS |
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The proportions of the mothers who were screened and seropositive for HBsAg were assessed. The receipt of the birth dose of hepatitis B vaccine among all infants and receipt of HBIG among infants who were born to HBsAg-positive mothers were also described. To examine risk factors for infant hepatitis B vaccination status, we performed univariate and multivariate analyses.
2 tests and logistic regression analyses were conducted using SPSS software version 9.0 and Epi Info version 6.0.
For rubella, the proportion of mothers who had documentation of rubella screening and the proportion of nonimmune women (including those with equivocal results) were assessed. We also assessed univariate and multivariate predictors of rubella immunity, as well as the relative immunity among age groups. Among rubella nonimmune women, the proportion that received postpartum rubella vaccination was evaluated.
| RESULTS |
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The odds of vaccination among infants who weighed
2500 g were 2.8 times (95% CI: 1.94.2) greater than the odds of vaccination among infants who weighed <2500 g. Similarly, the odds of vaccination among infants who were 37 or more weeks of gestational age were 3 times greater than the odds (95% CI: 2.14.3) among infants who were <37 weeks of gestational age. Infants with both low birth weight (<2500 g) and early gestational age (<37 weeks) were 75% less likely to receive the hepatitis B vaccination as compared with infants of normal birth weight and gestational age (relative risk: 0.25; 95% CI: 0.160.39).
Rubella Prevention
Almost all (99.4%) mothers were screened before delivery, either prenatally or during hospital admission (Table 2). Of these, 6.7% were rubella nonimmune. The highest proportion of nonimmune women were among the birth cohort born between 1971 and 1975 (9.5% nonimmune), who were 1.8 times more likely than women who were born from 1966 to 1970 to be rubella nonimmune (Table 4).
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| DISCUSSION |
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The overall 76.2% infant hepatitis B vaccination rate seen in this study is slightly lower than the 81% found in a 1996 survey (New Hampshire unpublished data 1996). In July 1999, the United States Public Health Service and the AAP recommended the temporary suspension of the birth dose of hepatitis B vaccine to infants who were born to HBsAg-negative women because of concerns at that time that thimerosal-containing vaccines could expose infants who were <6 months of age to cumulative levels of mercury that exceeded the federal guidelines for methyl-mercury.15,16 Although the suspension was lifted at the end of 1999, when manufacturers had removed thimerosal from most vaccines, including hepatitis B vaccine, the changes in policy statements have been shown to have an impact on newborn hepatitis B vaccine coverage levels.1719 These policy changes likely contributed to the delay in the resumption of the birth dose in early 2000 found in this study, with the lowest hepatitis B vaccination rates in January (48.5%) and February (67.5%). This is demonstrated by findings in records of infants who were born in January and February in a single hospital (n = 5) of a medical exemption form signed by the parent agreeing to delay HBV vaccination until the infant was 6 months of age because of concerns regarding thimerosal. It should be noted that thimerosal-free hepatitis B vaccine became available to New Hampshire birthing hospitals in December 1999 and that health care providers were informed of this by NH DHHS in late November 1999 (NH DHHS written communication, November 23, 1999). However, although there may have been a delay in resumption of administration of the birth dose, New Hampshire health care providers' newborn hepatitis B vaccination practices improved as the year progressed, with the highest vaccination rate seen in December 2000 (88.2%).
New Hampshire statute requires laboratories and health care providers, including hospitals, to report cases of HBsAg-positive pregnant women to the NH DHHS. This is important to ensure follow-up of their infants for completion of the 3-dose hepatitis B series and serologic posttesting, as well as to provide education and services (testing and, if appropriate, hepatitis B vaccination) for their sexual and household contacts. The finding that only 1 of 4 of the HBsAg-positive pregnant women found in this study was reported to the NH DHHS suggests that additional efforts are needed to improve compliance with reporting statutes, including ongoing education of all prenatal care providers, laboratories, and delivery hospitals.
Our findings highlight potential areas to improve perinatal hepatitis B prevention. First, attention must be given to accurate hepatitis B test ordering and processing, by laboratories as well as providers. Second, all maternal records should include a copy of prenatal laboratory reports to validate any handwritten notes and reduce the possibility of errors made in transcribing and/or interpreting test results. Third, providers need to be especially attentive to perinatal prevention among high-risk infants, such as those with low birth weight and gestational age <37 weeks.
In this study, 6.7% of pregnant women were rubella nonimmune, which is less than the 7.1% among women 13 to 51 years of age reported by a multistate cohort study20 and less than the 7.5% to 17.4% among women 12 to 49 years of age in the Third National Health and Nutrition Examination Survey.11 The relatively high immunity among New Hampshire women may be attributable, at least in part, to the relatively low (4.4%) foreign-born population in New Hampshire compared with the 11.1% foreign-born population in the United States as a whole21,22 (2000 US Census Bureau data). The age group with the highest level of rubella susceptibility (9.5%) in this study occurred among the 25- to 29-year-olds (born between 1971 and 1975), which is consistent with trends seen in Third National Health and Nutrition Examination Survey; this "lost generation" of young adults probably missed acquisition of rubella antibodies because they were too old to be affected by mandatory school entry vaccination, implemented by state immunization laws in the late 1970s, and not exposed to wild rubella virus infection because of widespread vaccination of younger cohorts.11,23
In this study, 75.6% of rubella nonimmune women received rubella vaccine, which is better than the 65.7% reported by Schrag et al20 in a multistate cohort study. Postpartum rubella vaccination rarely occurs outside the hospital setting,24 and failure to vaccinate a nonimmune woman before discharge is a missed opportunity for CRS prevention. When relevant documentation existed in the reviewed charts, "patient refusal" was the most frequent explanation (Table 2), suggesting that perhaps provider explanation of the risks and benefits of vaccination could be improved. Other means of improving postpartum vaccination rates is by implementing clear standing orders accompanied by protocols that include provider education.
It is important to note several limitations of this study. First, prenatal laboratory reports were not consistently available in hospital records and the accuracy of handwritten documentation of prenatal screening test results could not be verified. Second, the variety of rubella laboratory tests used, each with their differing cutoffs for immunity, may introduce error in our interpretation of rubella immunity patterns. Third, because the sampling of records was not supervised by the authors, selection bias possibly could have been introduced. In addition, these data are regional and may not reflect accurately the experience in other settings.
Despite these limitations, the large sample size allowed us to document rubella and hepatitis B perinatal prevention practices in the state of New Hampshire. Such benchmarking allows state health departments to monitor progress toward public health goals of perinatal hepatitis B and CRS elimination.
| ACKNOWLEDGMENTS |
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We acknowledge the administrators, infection control practitioners, maternity nurse managers, and medical records department directors of the 25 New Hampshire delivery hospitals for support and willingness to participate in this project. We thank Andrew Chalsma, Sheila Lazarro, and Andrew Pelletier from the NH DHHS for critical review of the proposal for this project, and the following NH DHHS staff for assistance in data collection: Chris Adamski, Ludmila Anderson, Marylee Greaves, Elizabeth Lincoln, and Jeannette Lozier. We thank John Copeland for assistance with sample size calculations and review of analysis and Sharon Bloom, Tasneem Malik, and Jane Seward for substantial comments on multiple versions of this manuscript.
| FOOTNOTES |
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Reprint requests to (S.B.) New Hampshire Department of Health and Human Services, Division of Public Health Services, 29 Hazen Dr, Concord, NH 03301-6504. sbascom{at}dhhs.state.nh.us
No conflict of interest declared.
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