Freshwater 20/1/09 3:08 pm Page 63
Viral Infections
Prevention and Management of Hepatitis B
a report by
Dennis Andrew Freshwater
Consultant Hepatologist, The Liver and Hepatobiliary Unit, Queen Elizabeth Medical Centre, Birmingham
Hepatitis B virus (HBV) infection is a global public health problem. It is Prevention of Transmission of Hepatitis B
estimated that there are more than 350 million HBV carriers in the Prevention of transmission of HBV requires attention to the likely
world, and approximately one million die annually from HBV-related liver routes of infection. Vaccination is the most effective measure to
disease.
1
In countries where HBV carrier rates reach 10%, HBV infection control and prevent hepatitis B and its long-term serious sequelae on
may account for 3% of total mortality, a level that exceeds polio-related a global scale, in terms of both cost-effectiveness and benefit–cost
mortality before the introduction of polio vaccine.
1
ratios.
8
According to the World Health Organization (WHO)
recommendations, universal vaccination has been implemented in 168
The prevalence of HBV carriers varies from 0.1 to 2% in low- countries worldwide with an outstanding record of safety and efficacy.
prevalence areas (Western Europe, US, Canada, Australia and New The effective implementation of such programmes of vaccination has
Zealand) to 3–5% in intermediate-prevalence areas (Mediterranean resulted in a substantial decrease in disease burden, in the carrier rate
countries, Japan, Central Asia, Middle East, Latin and South America) and in hepatitis B-related morbidity and mortality.
and up to 10–20% in high-prevalence areas (southeast Asia, China,
sub-Saharan Africa).
1,2
This is largely related to differences in the age The benefits of universal HBV vaccination for newborns and infants
at infection. are: a higher impact on chronic carrier rates and transmission; the
established potential of high vaccine coverage in this age group;
The rate of progression from acute to chronic HBV infection is opportunities to combine HBV vaccination with existing universal
approximately 90% for peri-natally acquired infection,
3
20–50% for vaccination programmes for newborns and infants; and impact on
infections acquired between one and five years of age
4,5
and less peri-natal transmission, if vaccination is started shortly after birth.
9
In
than 5% for adult-acquired infection.
5
Peri-natal infection is the areas of low prevalence, where a lower proportion of HBV infections
predominant mode of transmission in high-prevalence areas. In are acquired peri-natally, the WHO has recommended that the relative
comparison, horizontal transmission, particularly in early childhood, contribution of peri-natal HBV infection to the overall disease burden,
accounts for most cases of chronic HBV infection in intermediate- and the feasibility and cost-effectiveness of providing vaccination at
prevalence areas. Unprotected sexual intercourse, tattoos and birth, should be carefully considered before a decision is made on the
intravenous drug use in adults are the major routes of spread in low- optimal vaccination schedule.
prevalence areas.
Many countries with a low prevalence of HBV, including the UK, have
The high frequency of peri-natal transmission in endemic areas is declined to adopt a universal vaccination strategy. There should be
probably related to the high prevalence (40–50%) of the hepatitis B e antenatal screening of all mothers to detect HBsAg, and the current
antigen (HBeAg) in women of reproductive age. These women remain recommendation is to provide passive-active immunisation of
infectious because of the slow rate of HBeAg seroconversion during vaccination and hepatitis B immunoglobulin (HBIG) to newborns of
the first two decades of life.
6
Children may also acquire HBV through carrier mothers. Close family contacts of patients with chronic hepatitis
horizontal transmission via minor breaks in the skin or mucous B should be vaccinated in order to limit horizontal transmission.
membranes. In addition, HBV can survive outside the human body for
a prolonged period. Transmission via contaminated household articles Sexual transmission of hepatitis B can be prevented by vaccination of
such as toothbrushes or razors may be possible. sex partners in individuals with monogamous partners, and safe sex
Transfusion-acquired HBV was historically a significant route of
Dennis Andrew Freshwater is a Consultant Hepatologist in the
infection among adults, but the exclusion of paid blood donors and
Liver and Hepatobiliary Unit at the Queen Elizabeth Medical
the introduction of hepatitis B surface antigen (HBsAg) testing of Centre in Birmingham. He is a serving officer in the Royal
donated blood has reduced the prevalence to 0.6%.
7
Sexual
Navy, in which he holds the rank of Surgeon Commander. He
became a Member of the Royal College of Physicians (UK) in
transmission remains the major mode of spread of HBV in developed
1999. His current research and clinical interests include chronic
countries.
1,2
Heterosexual sex is estimated to account for 39% of new
viral hepatitis, as well as therapeutic endoscopy and ERCP. Dr
Freshwater graduated from University College London in 1992,
HBV infection among adults in the US, with transmission among men
and carried out his specialist training in the West Midlands.
having sex with other men accounting for 24%. Intravenous drug His post-graduate qualifications include a doctorate in medicine in 2007 for his thesis on the
usage accounts for 16% of new cases of HBV
5
and the risk of
evolution of hepatitis B and C in liver transplant recipients undergoing antiviral therapy.
transmission increases with the number of years of drug use, E: dennis.freshwater@uhb.nhs.uk
frequency of injection and sharing of drug preparation equipment.
© TOUCH BRIEFINGS 2008 63
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