Western Pacific Regional Plan for Hepatitis B Control Through Immunization
Worldwide, an estimated 350 million people have chronic hepatitis B virus (HBV) infections. In spite of being home to only 28% of the global population, the WHO Western Pacific Region bears a disproportionate burden of HBV-related mortality and morbidity, accounting for almost half of all chronic hepatitis B infections worldwide. With an estimated 160 million chronic HBV carriers living in the Region, hepatitis B is responsible for almost 890 deaths per day, a mortality rate comparable to that of tuberculosis. With few exceptions, most countries were estimated to have a chronic HBV infection rate of more than 8% before the introduction of vaccination. Of the 278 000 estimated deaths caused by HBV infection in the Region, nearly all were consequences of chronic infection, mostly decades after the initial infection at birth or in early childhood. Hepatitis B is, therefore, an important regional public health priority. Universal childhood immunization with three doses of hepatitis B vaccine in the first year of life has been proven to be the most effective strategy for prevention and control of hepatitis B. In 2002, the WHO Western Pacific Region became the first WHO Region to achieve the distinction of having infant hepatitis B immunization included in the national immunization programmes (NIPs) of all its Member States. Striving to build upon the gains achieved in immunization systems during the poliomyelitis eradication initiative, the Region has adopted hepatitis B control through universal childhood immunization as one of the pillars for strengthening immunization service delivery systems. In September 2005, the Western Pacific Region became the first WHO Region to set a time-bound goal of reducing chronic HBV infection rates to less than 2% among five-year-old children by 2012. For countries to achieve that goal, the key programmatic strategies will be:Strengthen routine immunization services to achieve and sustain at least 85% coverage (preferably 90%) with three doses of hepatitis B vaccine by one year of age in each birth cohort. At least 80% coverage to be achieved in each district. Establish a system to deliver a timely scheduled birth dose (within 24 hours of birth), with the target to reach at least 80% of births at each subnational level and at the national level. Institute catch-up immunization for older children, the first priority being children under five years of age, followed by those aged six to 15 years born before the start of vaccination, where resources allow and where infant immunization programmes, including delivery of a timely birth dose, are relatively mature. Institute immunization for high-risk population groups as the next priority after immunization of infants and younger children. However, immunization for health workers, among the high-risk population groups, can be taken as a priority along with infant immunization programmes because of the operational ease of identifying and accessing this population group. Achieve predictable financing for hepatitis B vaccine for at least the next three years on a continuous rolling basis to avoid any disruptions in the programme. Carry out advocacy and social mobilization activities. Include a hepatitis B control plan as an integral part of the multiyear plan for immunization programmes. Monitoring of hepatitis B immunization programmes is carried out primarily through coverage assessment, including monitoring of the percentage of newborn infants receiving a timely birth dose. The impact of vaccination programmes on HBV-related disease cannot be monitored like other vaccine-preventable diseases through regular disease surveillance because of the large number of asymptomatic infections, especially among children, the long time-lag before complications develop from chronic infection, and the fact that those complications are not exclusively caused by HBV. Therefore, the impact should be assessed through HBsAg seroprevalence surveys, along with regular monitoring of vaccine coverage rates. Countries should undertake at least one serosurvey in vaccinated cohorts to validate the impact expected from reported vaccine coverage rates.