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发表于 2003-9-13 15:47
MMWR Weekly
September 12, 2003 / 52(36);868-870
[B]Global Progress Toward Universal Childhood Hepatitis B Vaccination, 2003[/B]
In 1992, the World Health Organization (WHO) set a goal for all countries to
integrate hepatitis B vaccination into their universal childhood vaccination
programs by 1997. This report summarizes the global progress achieved toward
vaccination of children against hepatitis B virus (HBV) infection. Although
many countries have introduced hepatitis B vaccination into their national
vaccination programs, efforts are needed to increase coverage with the
3-dose hepatitis B vaccination series and expand vaccination programs into
countries where the vaccine has not yet been introduced.
In 2001, the most recent year for which complete program data are available,
126 (66%) of 191 WHO member states had universal infant or childhood
hepatitis B vaccination programs (1). Through these programs, an estimated
32% of children aged <1 year were vaccinated fully with the 3-dose hepatitis
B vaccination series. In the six WHO regions, the proportion of children
aged <1 year who were vaccinated fully was 65% in the Western Pacific
Region, 58% in the Americas Region, 45% in the European Region, 41% in the
Eastern Mediterranean Region, 9% in the South-East Asian Region, and 6% in
the African Region.
As of May 2003, a total of 151 (79%) of 192* WHO member states had adopted
universal childhood hepatitis B vaccination policies, including six that
have policies for vaccinating adolescents (Figure). Of the 137 member states
that have adopted universal childhood hepatitis B vaccination and for which
data are available, 76 (55%) have a policy for administering the first dose
of vaccine soon after birth (birth dose).
Of the 89 member states with historically high prevalences of chronic HBV
infection (i.e., prevalence of hepatitis B surface antigen [HBsAg] >8%) and
for which universal infant hepatitis B vaccination is recommended
specifically, 64 (72%) have adopted universal infant hepatitis B
vaccination. Of these 64 member states, 34 (53%) have a policy for
administration of a birth dose of vaccine. Goals for global hepatitis B
vaccination are for the vaccine to be introduced in all countries by 2007
and for coverage with the 3-dose hepatitis B vaccination series to reach 90%
by 2010 (2).
Reported by: M Gacic-Dobo, G Mayers, M Birmingham, DVM, Dept of Vaccines and
Biologicals, World Health Organization, Geneva, Switzerland. M Kane, MD,
Children's Vaccine Program, Program for Appropriate Technology in Health,
Seattle, Washington. SC Hadler, MD, Global Immunization Div, National
Immunization Program; MJ Perilla, MPH, FE Shaw, MD, ST Goldstein, MD, EE
Mast, MD, HS Margolis, MD, Div of Viral Hepatitis, National Center for
Infectious Diseases; T Samandari, MD, EIS Officer, CDC.
Editorial Note:
Each year, approximately 600,000 HBV-related deaths occur worldwide (CDC and
WHO, unpublished data, 2003). An estimated 93% of these deaths result from
the chronic sequelae of HBV infection: cirrhosis and hepatocellular
carcinoma (HCC) (CDC, unpublished data, 2003). Approximately 21% of
HBV-related deaths result from infection acquired in the perinatal period
and 48% from infection acquired in early childhood (age <5 years) (CDC,
unpublished data, 2003). Therefore, vaccination of infants and children is
the highest priority for hepatitis B vaccination programs. Three doses of
hepatitis B vaccine are 90%--95% efficacious in preventing HBV infection and
its chronic sequelae (3). To prevent perinatal HBV transmission, the first
dose of vaccine should be administered within the first 24 hours after birth
(3,4).
Hepatitis B vaccination has been shown to reduce the prevalence of chronic
HBV infection and the incidence of HCC dramatically. In The Gambia, the
prevalence of chronic infection among children declined from 10.0% to 0.6%
after implementation of universal infant hepatitis B vaccination (5).
Similar declines in prevalence of chronic infection associated with infant
and childhood hepatitis B vaccination have been demonstrated in China,
Indonesia, Senegal, and Thailand, and among Alaska Natives (6,7). After
implementation of universal infant hepatitis B vaccination in Taiwan, the
incidence of HCC among children declined from 0.7 to 0.36 per 100,000 (8).
Several important challenges remain to achieve the goal of global childhood
hepatitis B vaccination introduction. Countries that have not yet introduced
hepatitis B vaccine should do so. For many of these countries, this will
require strengthening their existing vaccination program infrastructure to
accommodate the addition of a new vaccine (9). In countries where the
vaccine has been introduced already, coverage with the 3-dose hepatitis B
vaccination series should be increased to that of the 3-dose
diphtheria-tetanus-pertussis (DTP) series, and then to >90%. Countries that
do not have a policy for administration of a birth dose of vaccine should
consider the feasibility of implementing such a policy. In countries with
high hepatitis B vaccination coverage among children, consideration should
be given to catch-up vaccination of older children, adolescents, and adult
populations at increased risk for HBV infection.
A major barrier to the introduction of hepatitis B vaccination has been the
high cost of hepatitis B vaccines. Although the price of monovalent
hepatitis B vaccine for developing countries has decreased from
approximately U.S.$3.00 per dose in 1990 to U.S.$0.30 per dose in 2001, the
cost remains higher than that of the older vaccines (e.g., DTP, oral polio,
and measles), which cost U.S.$0.06--$0.10 per dose. Since 1999, support from
the Global Alliance for Vaccines and Immunization (GAVI) and the Vaccine
Fund (VF) has accelerated introduction of hepatitis B vaccine in the world's
poorest countries (9). As of May 2003, of 75 countries eligible for GAVI/VF
support, 48 (64%) had received funding for hepatitis B vaccination
introduction.
Administration of a birth dose of vaccine presents a challenge. Worldwide,
approximately 50% of infants are born at home and do not have immediate
access to health care. However, because hepatitis B vaccine has been shown
to be heat stable, it could be administered by trained birth attendants to
infants born at home. The feasibility of such a strategy has been
demonstrated in Indonesia, where trained birth attendants were taught to
administer the birth dose of vaccine to infants born at home by using a
single-use, pre-filled injection device (10).
WHO, in collaboration with CDC and other GAVI partners, conducted process
evaluations of hepatitis B vaccination introduction in five African
countries where the vaccine had been introduced recently. These evaluations
demonstrated that hepatitis B vaccine introduction did not negatively impact
the existing vaccination programs, including coverage with the other
childhood vaccines. However, several problems were identified related to the
management of this relatively costly vaccine: vaccine freezing during
storage and shipment, and vaccine wastage. Outcome evaluations are needed to
document the impact of vaccination on the prevalence of chronic HBV
infection and HBV-related morbidity and mortality.
References
World Health Organization. WHO Vaccine Preventable Diseases Monitoring
System: 2002 Global Summary. Geneva, Switzerland: World Health Organization,
2002; document no. WHO/V&B/02.20.
Global Alliance for Vaccines and Immunization. GAVI Milestones, 2003.
Available at
http://www.vaccinealliance.org/home/General_Information/About_alliance/Background/milestones.php.
CDC. Hepatitis B virus: a comprehensive strategy for eliminating
transmission in the United States through universal childhood vaccination:
Recommendations of the Immunization Practices Advisory Committee (ACIP).
MMWR 1991;40(No. RR-13).
Yeoh EK, Young B, Chan YY, et al. Determinants of immunogenicity and
efficacy of hepatitis B vaccine in infants. In: Hollinger FB, Lemon SM,
Margolis HS, eds. Viral Hepatitis and Liver Disease. Baltimore, Maryland:
Williams & Wilkins, 1991.
Viviani S, Jack A, Hall AJ, et al. Hepatitis B vaccination in infancy in The
Gambia: protection against carriage at 9 years of age. Vaccine
1999;17:2946--50.
Kane MA. Status of hepatitis B immunization programmes in 1998. Vaccine
1998;16:S104.
Harpaz R, McMahon BJ, Margolis HS, et al. Elimination of new chronic
hepatitis B virus infections: results of the Alaska Immunization Program. J
Infect Dis 2000;181:413--8.
Chang MH, Chen CJ, Lai MS, et al. Universal hepatitis B vaccination in
Taiwan and the incidence of hepatocellular carcinoma in children. N Engl J
Med 1997;336:1855--9.
Martin JF, Marshall J. New tendencies and strategies in international
immunisation: GAVI and the Vaccine Fund. Vaccine 2003;21:587--92.
Otto BF, Suarnawa IM, Stewart T, et al. At-birth immunisation against
hepatitis B using a novel pre-filled immunisation device stored outside the
cold chain. Vaccine 2000;18:498--502.
* In September 2002, Timor Leste (East Timor) became a WHO member state |
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