1 Epidemiology and Surveillance Division, National Immunization Program, Centers for Disease Control and Prevention, Atlanta, GA.
2 Data Management Division, National Immunization Program, Centers for Disease Control and Prevention, Atlanta, GA.
3 Office of the Director, Centers for Disease Control and Prevention, Atlanta, GA.
Received for publication June 17, 2002; accepted for publication October 30, 2002.
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ABSTRACT |
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hepatitis B; hepatitis B surface antigens; patient compliance; perinatal care; prenatal care; serologic tests; vaccination
Abbreviations: Abbreviations: CI, confidence interval; ESPHB, Enhanced SurveillancePerinatal Hepatitis B Prevention Program; HBIG, hepatitis B immunoglobulin; HBsAg, hepatitis B surface antigen.
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INTRODUCTION |
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MATERIALS AND METHODS |
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Households were enrolled when an HBsAg-positive pregnant woman was reported to the health department, was asked to enroll, and agreed to be followed by the health departments ESPHB project staff. Data were collected on a pregnant woman from her physicians office and from her, through interviews with the ESPHB nurse. A six-page questionnaire was completed, by telephone or face-to-face, about the womans demographic profile and her knowledge, attitudes, practices, and barriers related to perinatal hepatitis B prevention. Barriers are any conditions that tend to make it difficult or problematic to receive the hepatitis B vaccination, such as not being allowed time off from work to take the infant in for shots, cost of the vaccination too high, waiting times at the clinic too long, lack of transportation to the physicians office, inconvenient hours that the physicians office or clinic is open for vaccinations, difficulty arranging child care to take the infant in for a shot, and lack of understanding of the importance of the hepatitis B shot. A hepatitis B-related risk profile and risk history were provided by the mother on her new infant and all children less than age 16 years in her household. Interviews using survey instruments similar to the ones used for the mother and children, with the addition of other adult-related risk factors, were attempted with all household members aged 16 years or older as well as with all identified sex partners inside or outside the household. (Data collection instruments are available from the first author.)
During the initial interview, each mother and adult contact was provided with health education, according to a standardized script, about perinatal hepatitis B. Screening and/or vaccination to prevent transmission of hepatitis B virus was offered for the infant and all other household members and sex partners. These prevention activities included, for the infants, hepatitis B immunoglobulin (HBIG) and the first dose of hepatitis B vaccine to be given within 12 hours of birth, followed by the second dose of vaccine at 12 months of age, the third dose of vaccine at 68 months of age, and postvaccination screening for antibodies to HBsAg 39 months after completion of the third dose or at age 1215 months if the hepatitis B vaccine series had not been completed on schedule. All household and sexual contacts were to be screened for a history of hepatitis B vaccination and for a positive HBsAg test, a positive antibody to HBsAg test, or a positive antibody to hepatitis B core antigen test. If they had no such history, they were to be tested for antibody to hepatitis B core antigen and for HBsAg. All who were found to be susceptible to hepatitis B virus were to receive the three-dose hepatitis B vaccine series at the recommended intervals of 0, 1, and 6 months. Interviews, vaccination, and screening took place at public health clinics, private providers offices, and in the home. The same questionnaires and most data collection forms were used at each of the four sites, with minor changes as needed.
Each study site followed the study protocol to varying degrees. In Texas, data collection started in April 1992 and ended in September 1999. The complete protocol was implemented throughout the entire study period at the Dallas site, but the Fort Worth site discontinued its involvement in the study before the first year ended. Michigan data collection started in January 1993 and ended in December 1995. Georgia data collection began in April 1994 and ended in June 1999. Connecticut gathered data from April 1994 to March 2000. This state collected postvaccination infant blood samples but conducted only the qualitative antibody test. Texas, Georgia, and Connecticut, which completed the study, enrolled new households, according to the protocol, until the end of December 1997. The follow-up form that documented the type and frequency of follow-up made by the ESPHB staff members was implemented fully by Texas and partially by Michigan and Connecticut. Georgia did not use the follow-up form.
The specific intervention methods used at each site varied because of differences in each organizational structure. In Dallas, the local health department used a team of public health workers to operate a centrally located public health clinic and to travel to homes, as needed, for in-home interventions. The team consisted of one nurse and several community health workers who could translate Spanish and several Asian languages. When interviews, blood draws, and/or vaccinations could not be arranged in the public health clinic, the team traveled to the womans home. In the Michigan and Connecticut study areas, the ESPHB patient contact was conducted primarily over the telephone. Most of the blood draws and vaccinations were arranged by private providers because there was no public health clinic. Telephone company translators were used extensively for interviews conducted in languages other than English. At the Georgia sites, state public health nurses worked with local county public health nurses to implement the study protocol. The state nurses conducted interviews; patient contacts in the public health clinics were the responsibility of the county nurses. Telephone translators were also used but to a lesser extent than in Michigan and Connecticut.
Household compliance with the recommended pre- and postvaccination screening and receipt of HBIG and hepatitis B vaccine by each household member and sexual contact were the primary outcomes of interest in this study. A binary variable indicating individual compliance status was created to assess association with demographic and hepatitis B-related knowledge, attitudes, practices, and barrier items obtained from the interview questionnaires. Bivariate analyses were performed to determine association of these variables with noncompliance. These items were further analyzed by using generalized estimating equations to obtain adjusted relative risks of household noncompliance. Household noncompliance was determined by using the individual compliance data from each household member and sex partner as a repeated measure of household compliance. Equal correlation among household members was assumed. Households were assumed to be independent. Version 8.2 of Statistical Analysis System software (SAS Institute, Inc., Cary, North Carolina), the GENMOD procedure with the REPEATED statement, was used to perform the generalized estimating equations analysis. The model parameter estimates were obtained by using the binary distribution with the log link function. Estimates were exponentiated to calculate the adjusted relative risks.
Since many explanatory variables were correlated with each other, only those from each group of correlated variables having the greatest association with noncompliance were kept in the multivariable model. Interactions between each ESPHB site and each variable in the model were evaluated for statistical significance at the 0.05 level.
Each member of the household was deemed either compliant or noncompliant by using the following process. Times from infants dates of birth to receipt of HBIG; vaccine doses 1, 2, and 3; and antibody screening were recorded. A mother whose infant received HBIG and dose 1 within 48 hours of birth and dose 3 within 240 days of birth was deemed compliant. (The 48-hour time period for HBIG and dose 1 was used because of the absence of charted time-of-day information regarding their administration.) Other members of the mothers household were classified as compliant if they received screening and dose 1 (if indicated) within 30 days of the mothers enrollment and dose 3 (if indicated) within 240 days of the mothers enrollment in the study. Noninfant household members who were screened on time and were found to be infected or immune were also considered compliant for analysis purposes.
The factors tested for association with compliance level were as follows: program siteAtlanta, Connecticut counties, Dallas (reference group), and Detroit urban areas; country of birthoutside the United States (reference) versus in the United States; hepatitis B endemicity level of birth countrygreater than or equal to 2 percent (reference) versus less than 2 percent; primary reading languagenon-English (reference) versus English; primary speaking languagenon-English (reference) versus English; distance from home to providergreater than or equal to 10 miles (16.1 km; reference) versus less than 10 miles; presence of barriers to understanding survey questions (when English was not the respondents primary language)yes (reference) versus no; member of a high-risk group (multiple sex partners, intravenous drug use, other sexually transmitted diseases, birth in a country with at least 2 percent endemicity)yes (reference) versus no; raceAsian and Pacific Islander (reference) versus other; age of motherat least 20 years (reference) versus less than 20 years; and household incomeat least $15,000 (reference) versus less than $15,000. Reference levels were those for persons at lowest risk, chosen such that relative risks would be greater than 1.0, thus simplifying interpretation of the model.
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RESULTS |
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Table 1 displays the hepatitis B screening and vaccination data for each site and combined. The total number of households enrolled in the ESPHB that met the criteria for adequate data was 1,458 and ranged from 130 in Detroit to 777 in Dallas. The number of noninfant household contacts identified per household for all ESPHB sites combined was 2.35 and varied somewhat across the four sites: Connecticut counties, 2.18; Dallas, 2.30; Atlanta, 2.41; and Detroit, 2.93. The rate of postenrollment screening among identified noninfant household contacts for all sites combined was 47 percent and varied widely across the four sites: Detroit, 19 percent; Atlanta, 27 percent; Connecticut counties, 41 percent; and Dallas, 61 percent.
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Vaccination start/finish rates for younger children were twice as high as those for older children in Atlanta, and the difference was almost as great in Detroit. However, in the other two sites and overall, start/finish rates were similar for both younger and older children. We looked at two age cutpointsat 6 years and at 10 years.
Postvaccination screening of infants varied from 86 percent in Connecticut counties and 81 percent in Dallas to 65 percent in Atlanta and only 9 percent in Detroit. Most infants who were screened were tested for both antibodies to HBsAg and for HBsAg, and the rates were 97 percent and 2.4 percent, respectively, as shown in table 2.
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The factor most strongly associated with lack of compliance was program site. Compliance was greatest among Dallas participants (table 3). The adjusted relative risks of noncompliance, with Dallas as the reference group, were as follows: Detroit, 2.14 (95 percent confidence interval (CI): 1.96, 2.34); Atlanta, 1.96 (95 percent CI: 1.78, 2.15); and Connecticut, 1.30 (95 percent CI: 1.13, 1.50).
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DISCUSSION |
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Although the same protocol was attempted at each of the four study sites, no two sites performed exactly the same steps; even those steps that were followed at each site were implemented in different ways. Most of the differences occurred because of the differences in organizational structure and interests of the decision makers in each of the health departments involved. These differences resulted in varying levels of success, as was evident by varied compliance indicators.
The ESPHB staff at the Dallas site was able to achieve higher rates of hepatitis B prevaccination serologic screening and vaccination rates that were double among adult contacts compared with those rates achieved at the other three ESPHB sites. The most likely reason is the home-visit program in Dallas. The number of nurse home visits per household was 2.2 in Dallas and zero in the other areas.
From the ESPHB results, it seems that the greater the number of perinatal hepatitis B prevention components that can be implemented by a self-contained centralized team, the higher the rates of pre- and postscreening and vaccination starts and completion, especially among household and sexual contacts. Of the four ESPHB sites, Dallas was the most completely centralized and self-contained regarding all components of perinatal hepatitis B prevention. Atlanta was the least centralized, with coordination housed at the state office and clinical services provided by staff in two county health departments as well as by many private providers. Connecticut was fairly centralized but, as in Detroit, had to rely totally on private providers for all clinical services.
The best comparison of compliance levels can be found in the perinatal hepatitis B prevention data reported from Immunization Program Grantees located in the United States (Centers for Disease Control and Prevention, Atlanta, Georgia, unpublished data). These data are reported annually by 49 states (Alaska does not screen pregnant women for HBsAg), five cities (Chicago, Illinois; Houston, Texas; New York, New York; Philadelphia, Pennsylvania; and San Antonio, Texas), and the District of Columbia (Washington, DC). The most recent complete data are those for 1999.
Compared with the national database, ESPHB rates were 37 percentage points higher regarding identification of infants, similar regarding on-time prophylaxis start rates, 16 percentage points higher concerning infant on-time series completion rates, and 33 percentage points higher on postvaccination serotesting of infants. In 1999, 9,503 infants born to HBsAg-positive women were identified by these grantees. These infants represented 47.5 percent of the expected number based on estimates from the Centers for Disease Control and Prevention of 20,000 infants born in the United States annually to HBsAg-positive women. (By comparison, the ESPHB identified 84.6 percent of the Centers for Disease Control and Preventions estimate of the expected number of these infants for the study sites.) Of the 9,503 infants identified in the United States, 8,368 (88.1 percent) received HBIG and the first hepatitis B vaccine dose at birth (ESPHB, 82.8 percent), 5,353 (56.3 percent) received HBIG and completed the hepatitis B vaccine series by age 68 months (ESPHB, 72.1 percent), and 3,797 (40.0 percent) were serotested (ESPHB, 73.0 percent).
ESPHB staff identified twice as many household and sexual contacts per infant as was reported to the national database; pretesting rates were 43 percentage points higher, and vaccination series start and finish rates were each 18 percentage points higher. In the households of these 9,503 infants identified by the immunization grantees, 10,944 household contacts were identified, an average of 1.15 household contacts per infant (ESPHB, 2.35). Twenty-six percent (2,868) were serologically tested for hepatitis B markers prior to vaccination (ESPHB, 69.1 percent), 892 (31.1 percent) had HBsAg (ESPHB, 11 percent), 826 (28.8 percent) had antibodies to HBsAg (ESPHB, 35 percent), 2,453 (26.6 percent of 9,226 who were susceptible or whose marker status was unknown) started the hepatitis B vaccine series (ESPHB, 45 percent), and 2,110 (22.7 percent) finished the series (ESPHB, 41 percent).
Higher rates of compliance by those born outside the United States might be attributed to higher awareness of the dangers of hepatitis B among these women and possibly a programmatic concentration on women with a high-risk background. Another contributing factor might be that language and cultural differences foster an attitude of deference to US medical practices among Asian and Pacific Islander and other foreign women.
On the basis of these study findings, a few strategies should be considered. Public-health-based efforts to encourage perinatal hepatitis B prevention should be as centralized and self-contained as possible to achieve the highest possible rates of identification, screening, and vaccination among all household members and sexual contacts. Providing in-home services to contacts who cannot or choose not to seek services at a clinic or providers office will also increase compliance with recommendations. The Dallas ESPHB model is one that can be duplicated to improve outcomes in jurisdictions in which perinatal services are provided in public clinics. The Connecticut ESPHB model can be duplicated to improve outcomes in jurisdictions in which perinatal services are provided solely by the private sector.
The ESPHB study results indicate that, compared with the national data, it may be possible for perinatal programs to achieve higher rates of infant and household identification; pre- and postvaccination serologic testing in contacts and infants, respectively; and hepatitis B vaccination among household contacts. A comprehensive program including home visits enhances compliance. Incorporating the strategies demonstrated here into perinatal hepatitis B prevention programs should increase the effectiveness of those programs.
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ACKNOWLEDGMENTS |
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NOTES |
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REFERENCES |
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