Hepatitis B (HBV)

Source: Deming, P. Viral Hepatitis. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7979809. Accessed May 31, 2012.

Acute or chronic viral infection of liver
Associated with development of:
- Chronic cirrhosis
- Hepatocellular carcinoma (HCC)

DNA virus, Hepadnaviridae family

Virion attaches to hepatocyte cell surface receptors and replicates.
HBV not pathogenic to cells
- Immune response to virus cytotoxic to hepatocytes.
- Destruction of heptocytes releases alanine transaminase (ALT), thus increasing levels.
Liver attempts to regenerate in environment of persistent inflammation, resulting in cirrhosis.
HCC develops after years of inflammatory processes provoked by ongoing HBV infection.

Infection transmitted:
- Parenterally (injection drug use)
- Perinatally
- Sexually

Prophylaxis with:
- HBV vaccine for active immunity (Table 1)
- HBV Ig for temporary passive immunity in postexposure cases
Vaccine side effects include:
- Soreness at injection site
- Headache
- Fatigue
- Irritability
- Fever
Immunization goals:
- Prevention of short-term viremia to limit:
  - Transmission of infection
  - Clinical disease
  - Chronic HBV infection

Table 1. Recommendations for Hepatitis B Virus (HBV) Vaccination

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Table 1. Recommendations for Hepatitis B Virus (HBV) Vaccination

Infants

Adolescents, including all previously unvaccinated children <19 years old

All unvaccinated adults at risk for infection

All unvaccinated adults seeking vaccination (specific risk factor not required)

Men and women with history of other STI and persons with history of multiple sex partners (>1 partner/6 months)

Men who have sex with men

Injection-drug users

Household contacts and sex partners of persons with chronic HBV infection and healthcare and public safety workers with exposure to blood in workplace

Clients and staff of institutions for developmentally disabled

International travelers to regions with high or intermediate levels (HBsAg prevalence ≥2%) of endemic HBV infection

Recipients of clotting factor concentrates

STI clinic patients

HIV patient/HIV-testing patients

Drug abuse treatment and prevention clinic patients

Correctional facilities inmates

Chronic dialysis/ESRD patients

Persons with chronic liver disease

ESRD, end-stage renal disease; HBsAg, hepatitis B surface antigen; HIV, human immunodeficiency virus, STI, sexually transmitted infection

Source: Centers for Disease Control and Prevention. A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of infants, children, and adolescents. MMWR 2005;54(RR-16):1–31.

No risk factors identified in majority of acute infections.
Sexual contact
- Multiple partners
- Men who have sex with men
- Known HBV-positive person
Injection-drug users
Household contact with HBV-positive person

Incubation period
- 4–10 weeks
- Highly infective
- Usually asymptomatic
Immunoactive (symptomatic) phase
- Intermittent hepatitis
- Marked increases in ALT
- Infants generally asymptomatic
- 85–95% of children ages 1–5 years asymptomatic
Seroconversion to anti-hepatitis B core antigen (anti-HbcAg)
- Chronic HBV (Table 2) diagnosed when detect hepatitis B surface antigen (HbsAg) and HbcAg and high serum titer of HBV DNA for >6 months (Table 3).
- Age most predictive factor for developing chronic HBV.
  - Perinatal infections almost always result in chronic HBV.
  - Chronic HBV risk
    - Infants: ...