Assessing Completeness of Perinatal Hepatitis B Virus Infection Reporting Through Comparison of Immunization Program and Surveillance Data --- United States

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Morbidity and Mortality Weekly Report (MMWR)

Assessing Completeness of Perinatal Hepatitis B Virus Infection Reporting

Through Comparison of Immunization Program and Surveillance Data --- United

States

Weekly

April 8, 2011 / 60(13);410-413

In the United States, an estimated 24,000 women with hepatitis B virus (HBV)

infection give birth each year (1). To prevent mother-to-child HBV transmission,

the Advisory Committee on Immunization Practices (ACIP) recommends administering

postexposure prophylaxis of hepatitis B vaccine (HepB) and hepatitis B immune

globulin (HBIG) to infants born to HBV-infected women within 12 hours of

delivery, followed by completion of the HepB series (2). In 1990, CDC

established a national Perinatal Hepatitis B Prevention Program (PHBPP) to

support federal immunization program grantees in performing this

ACIP-recommended case management of infants born to HBV-infected women.

Perinatal HBV infections currently are reported by state and local health

departments to CDC through two parallel processes: by immunization programs as

part of federal program grant reporting requirements and by communicable disease

surveillance units as part of the National Notifiable Diseases Surveillance

System (NNDSS). A review of perinatal HBV infection reporting for infants born

in 2005 identified 68 cases reported by immunization programs and 47 cases

reported by communicable disease surveillance units, resulting in a total of 73

unique cases, 42 (58%) of which were reported by both systems. Following

investigation, data reconciliation, and additional NNDSS reporting, 78 unique

cases were identified, 63 (84%) of which were reported by both systems. Improved

information-sharing between immunization programs and communicable disease

surveillance units of health departments is essential to ensure more complete

identification, case management, and quantification of perinatal HBV infections.

Accuracy and completeness of perinatal HBV infection reporting can help ensure

and measure progress toward elimination of HBV transmission in the United

States.

A case of perinatal HBV infection is defined as hepatitis B surface antigen

(HBsAg) positivity in any infant aged 1--24 months born in the United States or

its territories to an HBsAg-positive mother (3). Since 1995, PHBPP activities

have been reported to CDC through the Annual Immunization Program Report. Since

2001, communicable disease surveillance units have reported individual perinatal

HBV infection cases to CDC through NNDSS. During 2001--2004, an average of 38

perinatal HBV infection cases per year (range: 18--54) were reported through

NNDSS; during the same period, an average of 90 cases per year (range: 77--102)

were reported via the Annual Immunization Program Report.

To investigate this discordance, CDC reviewed all reports of perinatal HBV

infections in the two systems for infants born in 2005. To identify the 2005

birth cohort, NNDSS data entries from the reporting period January 1,

2005--March 30, 2007, were compared with those reported in the Annual

Immunization Program Report submitted in April 2007. Because reporting of

perinatal HBV infections through the annual report is in aggregate numbers and

not line-listed as it is through NNDSS, for this analysis CDC requested PHBPP

coordinators to share NNDSS case numbers and demographic information on

HBV-infected infants enumerated in the annual report. Cases reported through the

annual report or through NNDSS were then compared using infant date of birth,

NNDSS case number, sex, and race. PHBPP coordinators were informed of

discrepancies and asked to work with communicable disease surveillance unit

staff members responsible for NNDSS data entry to reexamine program reports and

NNDSS reports of perinatal HBV infections to resolve discrepancies.

Initially, 61 perinatal HBV infection cases were identified through NNDSS, and

86 were identified through the annual report (Figure 1). Fourteen cases reported

through NNDSS were excluded: 11 because of erroneous reporting (nine reports

actually were maternal HBV infections and not infant HBV infections, one infant

was not born in the United States, and one was a duplicate entry) and three

because of insufficient data to verify the case. Eighteen cases reported through

the annual report were excluded: 11 because of erroneous reporting (seven

infants not born in 2005 and four not HBsAg-positive) and seven (8%) because of

insufficient data to verify the case. Case matching was complicated by incorrect

or missing key data elements, such as race (eight annual report cases and 16

NNDSS cases), sex (one annual report case), and date of birth (two NNDSS cases).

Before case reconciliation, of the 73 unique cases reported by the two reporting

systems, 42 (58%) were reported by both (Figure 2). Case reconciliation included

obtaining more information on previously unverified cases, NNDSS reporting of

cases originally reported only in the annual report, and 7 months of additional

reporting to NNDSS. Following case reconciliation, 78 unique cases were

identified across the two reporting systems, with 63 (84%) reported by both

(Figure 3).

When asked to identify factors that influenced whether a case was reported by

both systems, health department staff members identified good communication

between PHBPP coordinators and communicable disease surveillance staff as an

important determinant of case reporting. Of 37 immunization program grantees who

responded, 28 (76%) indicated regular communication between persons responsible

for NNDSS data entry and the PHBPP coordinator before finalizing NNDSS data; 31

(84%) indicated that the PHBPP coordinator communicated with persons responsible

for NNDSS data entry before submission of the annual report. PHBPP staff members

reported that some incorrect or missed reporting resulted from misunderstanding

of the questions and because annual reports often were completed by a person

other than the PHBPP coordinator. Incorrect NNDSS reporting included

misclassifications of perinatal HBV infections as acute HBV or chronic HBV

infections and misclassifications of maternal HBV infections as perinatal HBV

infections.

Reported by

DM Roque, MD, Magee-Womens Hospital of Univ of Pittsburgh Medical Center,

Pennsylvania. SA Wang, MD,* A Wasley, ScD, Global Immunization Div; L

Jacques-Carroll, MA, S Roush, MPH, CM Weinbaum, MD, Immunization Svcs Div,

National Center for Immunization and Respiratory Diseases, CDC. *Corresponding

contributor: Wang, Global Immunization Div, National Center for

Immunization and Respiratory Diseases, CDC, +41 22 791 1606, sjw8@....

Editorial Note

Comparison of immunization program and communicable disease surveillance data

for reported perinatal HBV infections demonstrates a need for improved quality

and completeness of both reporting systems. Some infants were reported for the

wrong calendar year in the annual report, whereas case definitions were

misinterpreted (e.g., maternal infections were miscoded as perinatal infections)

in NNDSS. In the two reporting systems, 5%--8% of cases contained insufficient

data to verify cases, and 13%--18% of cases were erroneous reports.

At the local level, communicable disease surveillance staff members should

ensure that every infant with perinatal HBV infection is reported to the PHBPP

coordinator, so that immunization program staff can investigate whether failure

to vaccinate (i.e., gaps in clinical or program services) or vaccine failure

might have resulted in the perinatal HBV infection. In turn, PHBPP coordinators

should ensure that every infant with perinatal HBV infection is reported to the

communicable disease surveillance staff to ensure complete and accurate NNDSS

surveillance data for monitoring disease, evaluating and improving prevention

efforts, and allocating resources. Establishing joint cross-check procedures

between immunization program and surveillance staff members, such as ensuring

that each infected infant has a surveillance identification number, will help

make sure that immunization programs and surveillance units have accurate and

complete descriptions of all infants with perinatal HBV infection.

Although this analysis was performed to assess complete and accurate reporting

of detected perinatal HBV infections for surveillance and program activities,

increased case detection also is critically needed for achieving elimination of

HBV transmission in the United States (2). Because HBV-infected infants are

typically asymptomatic, case detection requires performing HBsAg testing of

at-risk infants. However, because fewer than half the estimated number of births

to HBV-infected women are identified through PHBPP (4) and only a fraction of

those infants undergo postvaccination testing (1), the actual number of

perinatal HBV infection cases is believed to be 10 to 20 times higher than the

number currently detected and reported (1).

Whereas adults who acquire HBV infection have a 95% likelihood of resolving the

infection and only a 5% risk for developing chronic HBV infection, infants who

become HBV-infected have a 90% risk for developing chronic HBV infection and a

25% lifetime risk for dying prematurely from cirrhosis or hepatocellular

carcinoma (1,2). Thus, the key strategy to eliminate morbidity and mortality

from HBV is to prevent infants from acquiring HBV infection. ACIP recommends

that all newborns receive their first HepB vaccination before hospital discharge

(2). For infants born to HBV-infected women, administering ACIP-recommended

postexposure prophylaxis of HBIG and HepB within hours of birth followed by

completion of the HepB series has been shown to be 85%--95% effective in

preventing HBV infection (2).

Multiple steps are involved in the prevention and monitoring of perinatal HBV

infection, including 1) identifying HBV-infected pregnant women, 2) providing

newborn infants with appropriate and timely postexposure prophylaxis, 3)

monitoring infants born to infected women to ensure completion of the HepB

series and to ensure HBsAg testing 1--2 months after the third HepB dose, and 4)

reporting of any HBV infections among infants. Eliminating perinatal HBV

transmission in the United States will require closing any gaps in this process

(5). Accurate counting of HBV-infected infants is needed to monitor progress

toward elimination of perinatal HBV infection, to know whether program and

vaccine are reducing that burden effectively, and to identify and address any

failures in program or vaccine when an infected infant is reported.

References <CUT>

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What is already known on this topic?

In the United States, enumeration of nationally notifiable diseases occurs

primarily through passive surveillance through the Nationally Notifiable Disease

Surveillance System, and underreporting is common.

What is added by this report?

The existence of a National Perinatal Hepatitis B Prevention Program to support

immunization programs in performing active identification of infants born to

women infected by hepatitis B virus (HBV) provided an opportunity to compare the

number of HBV-infected infants identified actively through the immunization

programs with the number of HBV-infected infants identified passively through

communicable disease surveillance. More infants were identified through active

identification by the immunization programs than by passive communicable disease

surveillance; however, gaps were observed in reporting by both programs and

disease surveillance.

What are the implications for public health practice?

Greater coordination and communication between immunization program and

communicable disease surveillance units in health departments is needed to

ensure that all identified perinatal hepatitis B cases are reported and that all

reported cases are followed up appropriately.