Seroprevalence of hepatitis B in two period birth cohorts of Bolivian children: effect of universal vaccination

Progress in vaccination towards hepatitis B control and elimination in the Region of the Americas

BACKGROUND

Over recent decades, the Region of the Americas has made significant progress towards hepatitis B elimination. We summarize the countries/territories' efforts in introducing and implementing hepatitis B (HB) vaccination and in evaluating its impact on HB virus seroprevalence.

METHODS

We collected information about HB vaccination schedules, coverage estimates, and year of vaccine introduction from countries/territories reporting to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF Joint Reporting Form on Immunization. We obtained additional information regarding countries/territories vaccination recommendations and strategies through communications with Expanded Program on Immunization (EPI) managers and national immunization survey reports. We identified vaccine impact studies conducted and published in the Americas.

RESULTS

As of October 2016, all 51 countries/territories have included infant HB vaccination in their official immunization schedule. Twenty countries, whose populations represent over 90% of the Region's births, have included nationwide newborn HB vaccination. We estimated at 89% and 75%, the regional three-dose series and the birth dose HB vaccination coverage, respectively, for 2015. The impact evaluations of infant HB immunization programs in the Region have shown substantial reductions in HB surface antigen (HBsAg) seroprevalence.

CONCLUSION

The achievements of vaccination programs in the Americas suggest that the elimination of perinatal and early childhood HB transmission could be feasible in the short-term. Moreover, the data gathered indicate that the Region may have already achieved the 2020 WHO goal for HB control.

Hepatitis B Virus Infection in the General Population of Iran: An Updated Systematic Review and Meta-Analysis

CONTEXT

The hepatitis B virus (HBV) is a major global public health problem, affecting more than 2 billion people worldwide. Accurate and updated data on HBV prevalence is important for further planning to control the infection. The aim of this study was to update the prevalence estimate of HBV infection in the general population of Iran.

EVIDENCE ACQUISITION

A systematic review was done for data on the prevalence of HBV infection in the general Iranian population published between Jan. 1, 1990, and Jan. 1, 2016, in both international and national databases, including PubMed, Scopus, Web of Science, Scientific Information Database, IranMedex, and Magiran. All papers with clearly described time and location of the study, proper sampling strategies, and proper analysis methods were included in the present study. Data were extracted by two independent reviewers. Prevalence of HBV infection with a 95% confidence interval (CI) was calculated using Stata software, version 13.

RESULTS

The polled estimated prevalence of HBV infection in the general population of Iran was 2.2 % (95% CI: 1.9% - 2.6%). The highest prevalence of HBV infection (8.9%, 95% CI: 7.6% - 10.2%) was reported from Golestan province, and the lowest prevalence (0.7%, 95% CI: 0.4% - 1.1%) was seen in Kermanshah province. The prevalence of HBV infection was estimated at 3% (95% CI: 2.2% - 3.8%) for Iranian males and 1.7% (95% CI: 1.2% - 2.3%) for Iranian females. The prevalence of HBV infection in the general population of Iran was 2.9% (95% CI: 2.5% - 3.4%) before 2010 and 1.3% (95% CI: 0.9% - 1.7%) after 2010.

CONCLUSIONS

In total, Iran was classified within the low-intermediate HBV prevalence areas (2% - 4%), while according to recent data (after 2010), Iran was classified within the low HBV prevalence areas (< 2%), indicating that preventive measures conducted in Iran have been effective.