Hepatitis B in the Western Pacific: Progress Toward Control, 2005–2017

In 1990, chronic hepatitis B virus (HBV) infection was highly endemic in the World Health Organization's Western Pacific Region (WPR): more than 8% of people carried the hepatitis B surface antigen (HBsAg). The region — 37 countries and areas with about 1.8 billion people, from China and Japan to Fiji, Guam and Tokelau — then set out to change that with vaccination. This report, by authors from WHO's Western Pacific office and CDC, measured the progress through 2017.

Why the birth dose matters

Hepatitis B vaccine (HepB) has been available since 1982. In more than 95% of recipients it gives lifelong protection against HBV — and against the 20%–30% increased lifetime risk of cirrhosis or liver cancer that comes with infection. Most infected infants and children have no symptoms, so the only reliable way to track chronic infection is to test representative samples of children for HBsAg.

Two doses are the measures that count:

• a timely birth dose (HepB-BD), given within 24 hours of birth;
• the third dose (HepB3).

The targets

These match WHO's global strategy, which aims for 1% or less by 2020 and 0.1% or less by 2030.

Vaccination coverage

By 2005, every country and area in the region had at least three HepB doses in its national schedule; by 2012, 34 of 36 gave a universal birth dose. Regional and global coverage, in percent:

In 2017, 15 (42%) of 36 countries and areas reached at least 95% birth-dose coverage and 18 (50%) reached 95% for the third dose. Coverage remained lowest in places such as Papua New Guinea, whose birth-dose coverage was 33% in 2017.

Infection in children

In 1990, prevalence among 5-year-olds was estimated above 8% in 22 (61%) of 36 countries and areas. By December 2017, all but Nauru and New Caledonia had completed serosurveys, and a panel of 10–15 independent experts — the Hepatitis B Immunization Expert Resource Panel, set up in 2007 — had verified 19 (53%) of them, and the region as a whole, as below 1%. Chronic infection in children had fallen below 1% in 25 (69%) of the 36.

A 2016 modeling study estimated regional prevalence at 0.93% among children born in 2012, and found that vaccination prevented more than 37 million chronic infections and more than seven million hepatitis B–related deaths over the lifetimes of children born between 1990 and 2014.

Places whose most recent survey still showed 1% or more:

What worked

Countries raised birth-dose coverage by:

• raising community awareness of the need for a timely birth dose;
• training health workers to give it;
• using the vaccine outside the cold chain. The monovalent birth-dose vaccine is highly heat-stable. Used for limited periods outside the usual 35°F–46°F (2°C–8°C), under monitored conditions, it is safe and effective, and it reaches places without reliable refrigeration or where many babies are born at home. This raised timely birth-dose delivery by 27% in Laos, 70% in China and 150% in the Solomon Islands;
• promoting births in health facilities. Cambodia and China encourage them so mothers and newborns are seen by a professional within 24 hours, which also links maternal and child health services with immunization.

Stopping transmission from mothers

Because so many chronic infections in children come from their mothers at birth, reaching 0.1% by 2030 requires more than vaccine. The triple elimination strategy adds screening at least 95% of pregnant women, giving hepatitis B immunoglobulin (HBIG) to exposed newborns, and antiviral drugs for eligible pregnant women. As of December 2017:

In Cambodia, modeling found an integrated package through the triple elimination platform could cut mother-to-child transmission of HBV by 76%, from 14.1% to 3.4% — preventing about 3,200 infant infections a year at $114 per disability-adjusted life-year.

What's still needed

The authors call for global and regional guidance on indicators for measuring whether transmission from mothers is being eliminated, on how often to run costly serosurveys, and on using models to estimate prevalence from program data.

Sources

Based on Woodring J, Pastore R, Brink A, Ishikawa N, Takashima Y, Tohme RA, "Progress Toward Hepatitis B Control and Elimination of Mother-to-Child Transmission of Hepatitis B Virus — Western Pacific Region, 2005–2017," Morbidity and Mortality Weekly Report 68(8), Centers for Disease Control and Prevention; a work of the United States government in the public domain. Original report.