Should hepatitis B vaccine be used for infants?

Immunization in the Neonatal Intensive Care Unit

Premature infants admitted to the neonatal intensive care unit are at risk for severe infections and infectious complications caused by vaccine-preventable diseases. Both maternal and neonatal vaccination prevent such infections and improve outcomes for premature infants. An understanding of vaccine efficacy, safety, and administration recommendations, as well as reasons for vaccine hesitancy among clinicians and caregivers, facilitate strategies for improving vaccination rates for infants in the neonatal intensive care unit. Timely vaccination of premature infants confers important protection and improves vaccination rates during childhood.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Aflatoxins, hepatocellular carcinoma and public health

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide, primarily affecting populations in the developing countries. Aflatoxin, a food contaminant produced by the fungi Aspergillus flavus and Aspergillus parasiticus, is a known human carcinogen that has been shown to be a causative agent in the pathogenesis of HCC. Aflatoxin can affect a wide range of food commodities including corns, oilseeds, spices, and tree nuts as well as milk, meat, and dried fruit. Many factors affect the growth of Aspergillus fungi and the level of aflatoxin contamination in food. Drought stress is one of the factors that increase susceptibility of plants to Aspergillus and thus aflatoxin contamination. A recent drought is thought to be responsible for finding of trace amounts of aflatoxin in some of the corn harvested in the United States. Although it’s too soon to know whether aflatoxin will be a significant problem, since United States is the world’s largest corn producer and exporter, this has raised alarm bells. Strict regulations and testing of finished foods and feeds in the United States should prevent a major health scare, and prevent human exposure to deleterious levels of aflatoxin. Unfortunately, such regulations and testing are not in place in many countries. The purpose of this editorial is to summarize the current knowledge on association of aflatoxin and HCC, encourage future research and draw attention to this global public health issue.

Review of 8 years of experience with Infanrix hexa (DTPa-HBV-IPV/Hib hexavalent vaccine)

Combination vaccines that include multiple antigens within one formulation are now widely accepted as an effective means of eliciting protection against several diseases at the same time. Owing to improvements in quality and convenient modes of administration, they have become part of routine pediatric practice. Hexavalent vaccines, including diphtheria, tetanus, pertussis, hepatitis B, polio and Haemophilus influenzae type b antigens represent the latest advance in the development of combination vaccines. Over 8 years since its first licensure, this review looks at the immunogenicity, efficacy and safety profile of the only hexavalent pediatric vaccine currently in use--Infanrix hexa (diphtheria, tetanus, acellular pertusis-hepatitis B virus-inactivated poliovirus vaccine/Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]; GlaxoSmithKline Biologicals, Rixensart, Belgium)--through published clinical trials and postmarketing surveillance data. These data show DTPa-HBV-IPV/Hib to be highly immunogenic and well tolerated across a range of different primary and booster vaccination schedules, as well as when administered concomitantly with other licensed vaccines (e.g., pneumococcal conjugate vaccine). Additional issues surrounding the use of hexavalent vaccines are also reviewed.

Benefits of early hepatitis B immunization programs for newborns and infants

Despite the availability of safe and effective hepatitis B virus (HBV) vaccines for >20 years, strategies targeting risk groups failed to sufficiently control hepatitis B disease at the population level; this is mainly because of difficulties in risk identification and in program implementation. Hence, the global burden of disease of HBV still is substantial. The World Health Organization recommends universal vaccination against hepatitis B to ultimately eliminate HBV; this recommendation had been progressively implemented to reach 168 countries with a universal program by the end of 2006. However, hepatitis B immunization is currently becoming endangered of losing its place on the agendas of governments, agencies, and international organizations, mainly because of the increasing success of these immunization programs and the interest in newer vaccine-preventable diseases and the related programs.This publication aims to show that vaccination programs targeting newborns and infants are preferable to achieve this goal. The benefits of universal HBV vaccination for newborns and infants are: higher impact on chronic carrier rate and transmission; established potential of high vaccine coverage in this age group; opportunities to combine HBV vaccination with existing universal vaccination programs for newborns and infants; and impact on perinatal transmission, if vaccination is started shortly after birth. Moreover, the safety, immunogenicity, and long-term efficacy of newborn and infant HBV vaccination have been proven extensively. In summary, newborn and infant HBV vaccination programs should be considered the preferred strategy, capable of providing important and sustained impact on global HBV incidence, even if they have a delayed impact on sexual transmission of HBV.

Bivalent inactivated hepatitis A and recombinant hepatitis B vaccine

Hepatitis A and B remain serious global public health problems. Monovalent vaccines against hepatitis A and B have been available for many years. Since 1996, licenses have been gradually introduced for different formulations and immunization schedules of the first combined vaccines against both diseases. Twinrix Adult (with conventional and accelerated schedules) is available for the immunization of individuals aged 16 years or older in Europe and 18 years or older the USA. Twinrix Pediatric, with its three-dose schedule, and AmBirix, with its two-dose schedule, are licensed in Europe for ages 1-15 years. These vaccines offer a single injection for satisfactory protection against hepatitis A and B and an excellent safety and reactogenicity profile in comparison with monovalent vaccines. This article focuses on immunogenicity of the vaccines and proposes expert opinion and future directions in this field.