Hepatitis B

Table of Contents

Disease Information

Overview

Also known as:  Serum hepatitis, Australian antigen hepatitis, epidemic jaundice

Responsibilities

  • Hospital: Report by IDSS, facsimile, phone, or mail
  • Lab: Report by IDSS, facsimile, phone, or mail
  • Physician: Report by facsimile, phone, or mail
  • Local Public Health Agency (LPHA): Follow-up is required. Report by IDSS, facsimile, phone, or mail

Iowa HHS
Disease Reporting Hotline: (800) 362-2736
Secure Fax: (515) 281-5698

A. Agent

Hepatitis B virus (HBV) is a small, double-shelled virus in the Hepadnaviridae family.  The virus has a small circular DNA genome that is partially double-stranded.  HBV contains numerous antigenic components, including HBsAg, hepatitis B core antigen (HBcAg), and hepatitis B e antigen (HBeAg).

B. Clinical Description

Symptoms & Onset:  The prodromal phase from initial symptoms to onset of jaundice usually lasts from 3 - 10 days.  It is nonspecific and is characterized by insidious onset of malaise, anorexia, nausea, vomiting, right upper quadrant abdominal pain, fever, headache, myalgias, skin rashes, arthralgias and arthritis, and dark urine, beginning 1 to 2 days before the onset of jaundice.  The jaundice phase is variable, but usually lasts from 1 - 3 weeks, characterized by jaundice, light or gray stools, hepatic tenderness and hepatomegaly (splenomegaly is less common).  During convalescence, malaise and fatigue may persist for weeks or months, while jaundice, anorexia, and other symptoms disappear.  Less than 10% of children and approximately 30% of adults will experience jaundice.

Complications:  Fulminant hepatitis occurs in about 1% - 2% of persons, with mortality rates of  63% - 93%.  About 200 - 300 Americans die of fulminant disease each year.  Although the consequences of acute HBV infection can be severe, most of the serious complications associated with HBV infection are due to chronic infection.  Those that are chronically infected are infected for life and can pass the virus to others, even without symptoms.  Approximately 10% of all acute HBV infections progress to chronic infection.  As many as 90% of infants who acquire HBV infection from their mothers at birth become chronic carriers.  Of children who become infected with HBV between 1 year and 5 years of age, 30% - 50% become chronic carriers.  By adulthood, the risk of becoming a chronic carrier is decreased to 6% - 10%.  Persons with chronic infection are often asymptomatic and may not be aware that they are infected, yet are capable of infecting others.  Chronic infection is responsible for most HBV-related morbidity and mortality, including chronic hepatitis, cirrhosis, liver failure, and hepatocellular carcinoma.  Chronic active hepatitis develops in more than 25% of chronic carriers, and often results in cirrhosis.  An estimated 3,000 - 4,000 persons die of hepatitis B-related cirrhosis each year in the United States.  Persons with chronic HBV infection are at 12 - 300 times higher risk of hepatocellular carcinoma than non-carriers.  An estimated 1,000 - 1,500 die each year in the United States of hepatitis B-related liver cancer.

C. Reservoirs

Humans are the only known reservoir.

D. Modes of Transmission

Spread:  HBV is transmitted by parenteral or mucosal exposure to HBsAg-positive body fluids from persons who are carriers or have acute HBV infection.  The highest concentrations of the virus are in the blood and serous fluids; lower titers are found in other fluids, such as saliva and semen.  Saliva can be a vehicle of transmission through bites; however, other types of exposure to saliva, including kissing, are unlikely modes of transmission.  There appears to be no transmission of HBV via tears, sweat, urine, stool, or droplet nuclei.

Person-to-person:  In the United States, the most important route of transmission is by sexual contact, either heterosexual or homosexual, with an infected person.  Fecal-oral transmission does not appear to occur.  However, transmission among homosexual men occurs possibly via contamination from asymptomatic rectal mucosal lesions.

Direct percutaneous inoculation by needles during injection drug use is another mode of HBV transmission.  Transmission of HBV may also occur by other percutaneous exposure, including tattooing, ear piercing, and acupuncture, as well as needle-sticks or other injuries from sharp instruments sustained by medical personnel.  These encounters account for only a small proportion of reported cases in the United States.  Breaks in the skin without overt needle puncture, such as fresh cutaneous scratches, abrasions, burns, or other lesions, may also serve as routes for entry. 

Contamination of mucosal surfaces with infective serum or plasma may occur in the laboratory during mouth pipetting, or by eye splashes or other direct contact with mucous membranes of the eyes or mouth, such as hand-to-mouth or hand-to-eye when contaminated with infective blood or serum.  Transfer of infective material to skin lesions or mucous membranes via inanimate environmental surfaces may occur by touching surfaces of various types of contaminated hospital equipment.  Contamination of mucosal surfaces with infective secretions could also occur with contact of semen.

Perinatal transmission from mother to infant at birth is very efficient.  If the mother is positive for both HBsAg and HBeAg, 70% - 90% of infants will become infected in the absence of postexposure prophylaxis.  The risk of perinatal transmission is about 20% if the mother is positive only for HBsAg; up to 90% of these infected infants will become HBV carriers.  An estimated 15% - 25% of these carriers will ultimately die at an early age of liver failure secondary to chronic active hepatitis, cirrhosis, or primary hepatocellular carcinoma.

E. Incubation period

The incubation period of HBV infection is an average of 60 - 90 days, with a range of 45 - 180 days.

F. Period of Communicability or Infectious Period

Persons with either acute or chronic HBV infection should be considered infectious any time that HBsAg is present in the blood.  When symptoms are present in persons with acute HBV infection, HBsAg can be found in the blood and body fluids of infected persons for several weeks before and days, weeks, or months after the onset of symptoms.  Persons who have chronic hepatitis B (known as carriers) will be positive for HBsAg and remain infectious indefinitely.

G. Epidemiology

The frequency of infection and patterns of transmission vary in different parts of the world.  Approximately 45% of the global population live in areas with a high prevalence of chronic HBV infection (>8% of the population is HBsAg-positive); 43% in areas with a moderate prevalence (2% to 7% of the population is HBsAg-positive); and 12% in areas with a low prevalence (<2% of the population is HBsAg-positive).

In China, Southeast Asia, most of Africa, most Pacific Islands, parts of the Middle East, and the Amazon Basin, 8% to l5% of the population carry the virus. The lifetime risk of HBV infection is greater than 60%, and most infections are acquired at birth or during early childhood, when the risk of developing chronic infections is greatest. In these areas, because most infections are asymptomatic, very little acute disease related to HBV occurs, but rates of chronic liver disease and liver cancer among adults are very high. In the United States, Western Europe, and Australia, HBV infection is a disease of low endemicity. Infection occurs primarily during adulthood, and only 0.1% to 0.5% of the population is chronically infected. Lifetime risk of HBV infection is less than 20% in low prevalence areas.

The incidence of reported hepatitis B in the U.S. peaked in the mid-1980s with about 26,000 cases reported each year.  Reported cases have declined since that time and fell below 10,000 cases for the first time in 1996.  In 1999, a provisional total of 6,495 cases were reported.  The decline in cases during the 1980s and early 1990s is generally attributed to reduction of transmission among homosexual men and injection drug users as a result of HIV prevention.

Reported cases of HBV infection represent only a fraction of cases that actually occur.  In 2009, a total of 3,374 cases of acute hepatitis B were reported to CDC, resulting from an estimated 38,000 new infections. Because many HBV infections are either asymptomatic or never reported, the actual number of new infections is estimated to be approximately tenfold higher. An estimated 800,000 to 1.4 million persons in the United States are chronically infected with HBV and an additional 5,000 – 8,000 persons become chronically infected each year.

H. Bioterrorism Potential

None

I. Additional Infomation

The Council of State and Territorial Epidemiologists (CSTE) surveillance case definitions should not affect the investigation or reporting of a case that fulfills the criteria in this chapter. (CSTE case definitions are used by the state health department and the CDC to maintain uniform standards for national reporting.)

Fact Sheets and Forms

References

American Academy of Pediatrics. 2006 Red Book: Report of the Committee on Infectious Diseases, 27th Edition. Illinois, American Academy of Pediatrics, 2006.

CDC. 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). MMWR. 2005;  54(RR16);1-23

CDC. Immunization of Healthcare Workers: Recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC). MMWR. 1997; 46:RR-18

Heymann, David L., ed., Control of Communicable Diseases Manual, 20h Edition. Washington, DC, American Public Health Association, 2015.

Epidemiology and Prevention of Vaccine Preventable Diseases, Ninth  Edition, January 2006, Department of Health and Human Services, Centers for Disease Control and Prevention.

Resources

www.cdc.gov/ncidod/diseases/hepatitis/b/index.htm