Hepatitis B Transmission and Vaccination: Key Questions Answered

Q: Hepatitis B Transmission and Vaccination: Key Questions Answered

Hello, Xiao Dou：<br>1. <br>In patients with hepatitis B, the virus HBV-DNA can be detected in saliva, semen, and vaginal secretions, indicating sexual transmission. <br>According to foreign literature, the transmission rate among heterosexuals is approximately 39%, particularly a

Hepatitis B issues

Hello Dr.
Lin: (1) What is the probability of transmitting Hepatitis B through saliva and semen? (2) If a person has developed antibodies against Hepatitis B, can they be assured that they will not be infected regardless of contact with a Hepatitis B carrier? (3) For individuals without Hepatitis B antibodies, can receiving the vaccine eliminate the risk of contracting Hepatitis B?

Xiao Dou, 20~29 year old female. Ask Date: 2008/04/30

Dr. Lin Minghui reply Gastroenterology and Hepatology

Hello, Xiao Dou:
1.
In patients with hepatitis B, the virus HBV-DNA can be detected in saliva, semen, and vaginal secretions, indicating sexual transmission.
According to foreign literature, the transmission rate among heterosexuals is approximately 39%, particularly among those with multiple partners, highlighting the importance of avoiding risky sexual behaviors.
Among homosexual men in the United States, the transmission rate is about 24%.
Early domestic studies have reported that heterosexual contact is the most significant route of transmission for acute hepatitis B among adults in Taiwan.
In a study of 60 acute hepatitis B patients, 83% reported heterosexual contact as the only identified risk factor.

2.
The detection rate of HBV in the saliva of acute hepatitis B patients is as high as 76%, while the detection rate in asymptomatic carriers is 37%.
Another study found that in eAg-positive patients, the HBV-DNA positivity rate in the blood was 100%, and in saliva, it was 47%.
For eAg-negative hepatitis B patients, the HBV-DNA positivity rate in the blood was 58.5%, and in saliva, it was 17%.
This indicates that hepatitis B patients carry a certain amount of the virus in their saliva, which can facilitate transmission through saliva.
3.
The primary mode of transmission for hepatitis B is through infected bodily fluids and blood entering the bloodstream via broken skin or mucous membranes.
The likelihood of transmission is related to the viral load, the infectivity of eAg, and the immune status of the infected individual.
4.
Generally, individuals with hepatitis B antibodies are not at risk of contracting the virus.
5.
Vaccination theoretically provides immunity, and about 85% of individuals will develop antibodies after completing the three-dose vaccine series.
However, antibody levels may decline to below effective concentrations approximately 10 years post-vaccination, and some individuals may require a booster.
Wishing you good health,
Dr.
Lin Ming-Hui, Taoyuan Hospital, Department of Health

Reply Date: 2008/04/30

More Info

Hepatitis B is a viral infection that affects the liver and can lead to serious health issues, including chronic liver disease and liver cancer. Understanding its transmission, vaccination, and the body's immune response is crucial for prevention and management. Let's address your questions one by one.

1. Transmission through Saliva and Semen: The risk of transmitting Hepatitis B through saliva is considered to be low. While the virus can be present in saliva, it is not typically transmitted through casual contact or sharing utensils. In contrast, the risk of transmission through semen is significantly higher. Hepatitis B is primarily transmitted through blood, sexual contact, and from mother to child during childbirth. Therefore, while saliva may contain the virus, the likelihood of transmission through this medium is minimal compared to blood and sexual fluids.

2. Immunity from Natural Antibody Production: If a person has developed antibodies against Hepatitis B (anti-HBs), it indicates that they have either cleared a past infection or have been vaccinated. In either case, they are considered immune to the virus. This means that they are unlikely to contract Hepatitis B from exposure to an infected individual, including contact with bodily fluids. However, it is important to note that immunity can wane over time, and regular monitoring of antibody levels may be advisable, especially for those at higher risk.

3. Vaccination and Protection Against Hepatitis B: For individuals who do not have antibodies against Hepatitis B, vaccination is the most effective way to prevent infection. The Hepatitis B vaccine is highly effective, and after completing the vaccination series, most individuals will develop protective antibodies. This means that vaccinated individuals can significantly reduce their risk of contracting Hepatitis B, even if they come into contact with the virus. However, it is essential to complete the full vaccination series and have follow-up blood tests to confirm that adequate immunity has been achieved.

In summary, while the risk of transmission through saliva is low, the risk through semen is significant. Individuals with natural immunity (anti-HBs positive) are generally protected from infection, while those without immunity should receive the vaccine to prevent Hepatitis B. Regular monitoring and follow-up with healthcare providers are crucial for managing health and ensuring adequate protection against this virus.

Additionally, it is important to practice safe behaviors, such as using protection during sexual activity and avoiding sharing personal items that may come into contact with blood, to further reduce the risk of transmission. If you have concerns about potential exposure or vaccination status, consulting with a healthcare provider for personalized advice and testing is recommended.

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