How Hepatitis Viruses Are Transmitted
Hepatitis viruses are transmitted through specific exposure routes including blood contact, sexual activity, fecal-oral contamination, and perinatal transmission, with each virus having predominant transmission patterns that determine prevention strategies. 1, 2
Transmission Routes by Hepatitis Type
Hepatitis A (HAV)
- Primary transmission: Fecal-oral route 1
- Person-to-person contact during community outbreaks
- Contaminated food or water
- Household or sexual contact with infected persons (12-26% of cases)
- Peak infectivity occurs 2 weeks before jaundice appears 1
- High-risk groups:
- Injection drug users (5-19% of cases)
- Men who have sex with men (MSM), especially those with oral-anal contact 1
- Travelers to endemic areas
- Close contacts of infected individuals
Hepatitis B (HBV)
- Primary transmission: Blood and body fluids 1, 2
- Infectious body fluids:
- Blood (highest viral titers)
- Semen, vaginal secretions, saliva
- HBV is 100 times more infectious than HIV and 10 times more infectious than HCV 2
- Environmental persistence: Viable on surfaces for at least 7 days 2
Hepatitis C (HCV)
- Primary transmission: Percutaneous blood exposure 1
- Injection drug use (most common route)
- Contaminated medical equipment
- Blood transfusions (prior to screening)
- Less efficient transmission:
- Sexual contact (especially with multiple partners) 1
- Perinatal transmission (5-10% risk)
- Household contact (rare)
Special Considerations for Transmission
Healthcare Settings
- Healthcare workers face risk through:
- Needlestick injuries
- Mucosal exposure to blood/body fluids
- Percutaneous injuries (7% reported exposure) 1
Correctional Settings
- High prevalence of risk factors:
- Injection drug use history
- Unprotected sexual activity
- Tattooing with contaminated equipment 1
Pregnancy and Perinatal Transmission
- HBV: High risk of mother-to-child transmission
- 95% preventable with timely HBIG and vaccination of newborns 1
- HCV: Lower risk of vertical transmission
- Universal screening now recommended for pregnant women 1
- HAV: Rare vertical transmission, primarily during third trimester 1
Prevention Strategies
Hepatitis A
- Vaccination for high-risk groups
- Good hand hygiene
- Safe food and water handling
Hepatitis B
- Vaccination:
- Universal infant vaccination
- Vaccination of high-risk adults
- Sexual and household contacts of carriers 1
- Blood precautions:
- Screening of blood products
- Safe injection practices
- Perinatal prevention:
- Screening pregnant women
- HBIG and vaccine for infants of infected mothers 1
- Behavioral measures for carriers:
- Cover open cuts and scratches
- Clean blood spills with bleach
- No sharing of toothbrushes or razors
- Use barrier protection during sex with unvaccinated partners 1
Hepatitis C
- No vaccine available
- Screening high-risk populations
- Safe injection practices
- Avoiding sharing drug paraphernalia
- Treatment of infected individuals to prevent transmission
Common Pitfalls in Understanding Transmission
- Misconception: All hepatitis viruses are transmitted the same way
- Reality: Each has distinct primary transmission routes
- Misconception: Casual contact spreads hepatitis
- Reality: Normal social contact doesn't transmit hepatitis viruses
- Misconception: Hepatitis B carriers can't breastfeed
- Reality: Breastfeeding is generally safe for HBV carriers 2
- Misconception: Fecal precautions needed for all hepatitis types
- Reality: Only HAV is efficiently transmitted via fecal-oral route 3
Understanding these transmission routes is essential for implementing appropriate prevention strategies and reducing the global burden of viral hepatitis infections.