Abbreviated Name:
Hepatitis B incidence
Indicator Name:
Estimated number of new hepatitis B infections per 100 000 population in a given year
Domain:
Health status
Related Terms:
Morbidity
Definition:
The number of new hepatitis B infections per 100 000 population in a given year is estimated from the prevalence of total antibodies against hepatitis B core antigen (Total anti-HBc) and hepatitis B surface antigen (HBsAg) positive among children 5 years of age, adjusted for sampling design.
Measurment Method:
Total anti-HBc reflect cumulated incidence in the first five years of life while HBsAg reflect chronic infections that may evolve towards chronic liver diseases The sample of the serological survey must be drawn from the specific geographic region to be verified. For example if the purpose is to estimate national transmission of HBV (including mother-to-child transmission) then the sampling should be geographically representative of the population. Convenience sampling is not appropriate. The sample size should be adequate to show with 95% confidence HBsAg prevalence of less than 1% with a precision of ± 0.5%.
The target age is 5-years-old. Sampling 4– 6 year olds may be appropriate.
The serosurvey is cross sectional and therefore a point estimate time. The shorter time periods of data collection are therefore preferred.
Data on HBV birth dose exposure and B3 completion are drawn from official records. Where these are not available testing for HBsAb may be considered for the serosurvey. This is less preferable as it is more costly, but can also be done in addition.
Specimen collection and transportation should be appropriate to minimize bias though specimen degradation in rural and remote areas.
Where possible, it is advantageous to collect blood specimens for ELISA laboratory testing because the accuracy (sensitivity and specificity) is higher than for rapid tests. However in some locations only rapid tests will be available hence test selection is resource dependent. This should be considered in designing overall study methodology.
When an appropriate sampling strategy and size are used and quality testing assays and laboratory procedures are employed, the HBsAg prevalence in the serosurvey should be representative of the incidence of childhood HBV transmission in the specific geographic region (or country) in this age group
The target age is 5-years-old. Sampling 4– 6 year olds may be appropriate.
The serosurvey is cross sectional and therefore a point estimate time. The shorter time periods of data collection are therefore preferred.
Data on HBV birth dose exposure and B3 completion are drawn from official records. Where these are not available testing for HBsAb may be considered for the serosurvey. This is less preferable as it is more costly, but can also be done in addition.
Specimen collection and transportation should be appropriate to minimize bias though specimen degradation in rural and remote areas.
Where possible, it is advantageous to collect blood specimens for ELISA laboratory testing because the accuracy (sensitivity and specificity) is higher than for rapid tests. However in some locations only rapid tests will be available hence test selection is resource dependent. This should be considered in designing overall study methodology.
When an appropriate sampling strategy and size are used and quality testing assays and laboratory procedures are employed, the HBsAg prevalence in the serosurvey should be representative of the incidence of childhood HBV transmission in the specific geographic region (or country) in this age group
Numerator:
Number of survey participants with Total anti-HBc and HBsAg positive test.
Denominator
Number in survey with Total anti-Hc/HBsAg result.
Estimation method:
N/A
Disaggregation:
Dependent on sampling methodology. Exposure to the birth dose hepatitis B vaccine (official records), exposure to three doses of hepatitis B vaccine, place of residence
Primary data sources:
Serosurvey
Alternate data sources:
N/A
Measurment frequency:
Intermittent, dependent on population seroprevalence of HBsAg before hepatitis B immunization and
infant hepatitis B vaccination coverage
infant hepatitis B vaccination coverage
