Description

Hepatitis B infections are caused by the hepatitis B virus (HBV), a DNA virus that is in the Hepadnaviridae family. HBV can lead to a spectrum of liver disease ranging from acute hepatitis to chronic conditions such as cirrhosis or hepatocellular carcinoma (HCC).

Epidemiology

• Predominant age: can infect patients of all ages
• Predominant sex: fulminant HBV: male > female (2:1)
• In the United States, ~3,200 cases of acute HBV in 2016
• African Americans have the highest rate of acute HBV infection in the United States.
• Overall rate of new infections is down over 80% since 1991 (due to national immunization strategy). There has been a slight increase in new infections since 2014 (associated with increased IV drug use).
• Vaccine coverage for the birth dose ~72% in U.S.

• In the U.S., 800,000 to 1.4 million with chronic HBV
• Asia and the Pacific Islands have the largest populations at risk for HBV.
• Chronic HBV worldwide: 350 to 400 million persons
  • 1 million deaths annually
    • Second most important carcinogen (behind tobacco)
    • Of chronic carriers with active disease, 25% die due to complications of cirrhosis or HCC.
    • Of chronic carriers, 75% are Asian.

Etiology and Pathophysiology

HBV is a DNA virus of the Hepadnaviridae family; highly infectious via blood and secretions

Genetics
Family history of HBV and/or HCC

Risk Factors

• Screen the following high-risk groups for HBV with HBsAg/sAb. Vaccinate if seronegative (1)[A]:
  • Persons born in endemic areas (45% of world)
  • End-stage renal disease (dialysis)
  • IV drug users (IVDUs), past or present
  • Men who have sex with men (MSM)
  • HIV- and HCV-positive patients
  • Individuals with chronic liver disease (2)
  • Household members of HBsAg carriers
  • Sexual contacts of HBsAg carriers
  • Inmates of correctional facilities
  • Patients with chronically elevated AST/ALT levels
• Additional risk factors:
  • Needle stick/occupational exposure
  • Recipients of blood/products; organ transplants
  • Intranasal drug use; body piercing/tattoos
  • Survivors of sexual assault

Pediatric Considerations

• Shorter acute course; fewer complications
• 90% of vertical/perinatal infections become chronic.

Pregnancy Considerations

• Screen all prenatal patients for HBsAg (1)[A].
• If HBsAG (+), obtain HBV DNA.
• Consider treating patients with high viral load at 28 weeks or history of previous HBV (+) infant with oral nucleos(t)ide medication beginning at 32 weeks to reduce perinatal transmission (3)[C].
• Infants born to HBV-infected mothers require hepatitis B immune globulin (HBIg) (0.5 mL) and HBV vaccine within 12 hours of birth.
• Breastfeeding is safe if HBIg and HBV vaccines are administered and the areolar complex is without fissures or open sores. Oral nucleos(t)ide medications are not recommended during lactation.
• HIV increases risk of vertical transmission.
• Continue medications if pregnancy occurs while on an oral antiviral therapy to prevent acute flare.

General Prevention

• Vaccination
  • Three IM injections at 0, 1, and 6 months in infants or healthy adults (4)
  • All infants at birth and during well-child care visits (age 1 and 6 months)
  • All at-risk patients (see “Risk Factors”)
  • Health care and public safety workers
  • Sexual contacts of HBsAg carriers
  • Household contacts of HBsAg carriers
• Proper hygiene/sanitation by health care workers, IVDUs, and tattoo/piercing artists
  • Barrier precautions, needle disposal, sterilize equipment, cover open cuts
• Do not share personal items exposed to blood (e.g., nail clipper, razor, toothbrush).
• Safe sexual practices (condoms)
• HBsAg carriers cannot donate blood or tissue.
• Postexposure (e.g., needle stick):
  • HBIg 0.06 mL/kg in <24 hours in addition to vaccination (no more than 7 days after exposure)
  • Second dose of HBIg should be administered 30 days after exposure

Commonly Associated Conditions

• HIV, hepatitis C coinfection
• Extrahepatic manifestations include (5):
  • Serum sickness-like syndrome (fever, erythematous skin rash, myalgias, arthralgias, fatigue)
  • Glomerulonephritis (membranous or membranoproliferative glomerulonephritis, IgA-mediated nephropathy)
  • Polyarteritis nodosa