This is an automatically translated article.
The article was professionally consulted by Doctor I CK I Le Duc Tuyen, Department of Pediatrics - Neonatology, Vinmec Ha Long International General Hospital.Hepatitis B is transmitted mainly through blood, sex and from mother to child. The disease can be effectively prevented by vaccination, but the protection effect cannot be absolute, so if the hepatitis B vaccine is fully vaccinated, it is possible to be infected again or not, especially transmission. sexually?
1. What is Hepatitis B?
Hepatitis B is a dangerous infectious disease, causing acute and chronic liver damage, caused by the hepatitis B virus. Hepatitis B is a global health problem today, getting as much attention as cancer and non-communicable diseases.Worldwide, 2 billion people have been infected with the hepatitis B virus at some point in their lives. Currently, there are nearly 400 million people infected with hepatitis B globally and about 1 million people die each year, mainly due to complications such as cirrhosis and liver cancer.
Vietnam is located in an area with a high rate of hepatitis B virus infection. Currently, nearly 9 million people are infected with the hepatitis B virus (about 9% in women and 12% in men). This is the main cause of liver cancer and cirrhosis in our country.
Virus viêm gan B
2. How is the hepatitis B virus spread?
Hepatitis B virus is abundant in blood and body fluids such as semen and vaginal fluids. Hepatitis B virus is also present in other fluids such as saliva, tears, milk, and urine, but in very small amounts, it is not enough to be transmitted through these routes. Therefore, there are 3 routes of hepatitis B infection: through blood, sexual contact, and mother-to-child transmission.2.1. Blood-borne transmission A person can become infected with hepatitis B through blood when: The blood of a person infected with hepatitis B is introduced into the blood of an uninfected and unprotected person. Circumstances of being infected with hepatitis B through blood, such as:
Transfusion of blood from a person with hepatitis B to others Sharing syringes, direct contact with the blood of an infected person through an open wound Sharing utensils having a high risk of blood contamination such as toothbrushes, razors... with infected people, performing bleeding procedures (tooth extraction, tattooing...) Sharing surgical instruments without treatment good sterility...
2.2. Mother-to-child transmission A mother infected with hepatitis B has a high risk of passing it on to her baby during pregnancy. This is the main route of transmission of hepatitis B in the world today. About half of infections are transmitted through this route. Transmission from mother to child mainly occurs during childbirth, during pregnancy, the infection rate is very low, only about 2%.
The risk of mother-to-child transmission depends on the extent of hepatitis B virus replication in the mother's body and the amount of hepatitis B virus in the mother's blood. The rate of mother-to-child transmission of hepatitis B is higher if the mother is infected with hepatitis B in the presence of HBeAg. The presence of HBeAg antigen indicates that the amount of virus in the blood is multiplying and the patient is highly infectious. If HBeAg is positive, the mother-to-child rate is about 90%.
2.3. Sexually transmitted hepatitis B can be transmitted through sexual contact through contact with semen, vaginal fluids, blood (if there is skin damage), hepatitis B is more easily transmitted through sex. 50 to 100 times that of HIV.
Forms of sex that cause mucosal damage and bleeding, the higher the risk of hepatitis B infection, such as: oral sex, anal sex, same-sex sex, sex with many sex partners or sex with boys or prostitutes.
Viêm gan B không lây qua các tiếp xúc thông thường như bắt tay, ôm, hôn hay dùng chung thực phẩm, nước uống.
3. Can hepatitis B vaccine prevent the disease?
Fortunately, hepatitis B is preventable with full vaccination.Hepatitis B vaccine was started in 1982 and is now used in most countries around the world. In Vietnam, hepatitis B vaccine has been included in the National Expanded Immunization Program for all children born. Children are vaccinated with 4 doses of hepatitis B vaccine in the first 24 hours after birth, in the 2nd, 3rd and 4th months of the 5-in-1 combination vaccine containing hepatitis B component. In addition, in service immunization, hepatitis B also is repeated 1 time in children aged 18 - under 24 months in a 6-in-1 vaccine against diphtheria - pertussis - tetanus - polio - HiB pneumonia and hepatitis B.
Hepatitis B vaccination only works Used to prevent disease for people who have not been infected with the hepatitis B virus. Vaccination helps the body to produce antibodies to fight the hepatitis B virus to avoid infection with the virus in the future. If vaccinated fully and correctly, the protection of hepatitis B vaccine can be about 95% for children and adults. For people over 40 years of age, the effectiveness of protection is about 90%. The protective effect can last for about 15-20 years and can be longer depending on the person.
Tiêm vacxin viêm gan B đầy đủ giúp phòng bệnh hiệu quả.
4. Can hepatitis B be sexually transmitted when fully vaccinated?
The protective effect after hepatitis B vaccination will be determined by the concentration of anti-HBsAg antibodies (called anti-HBs or HBsAb) in the blood of the vaccinated person. The higher the concentration of anti-HBs, the higher the protective effect. Anti-HBs concentrations above 10 mIU/ml have a protective effect, anti-HBs concentrations above 100 mIU/ml have very high immunogenicity, and anti-HBs concentrations below 10 mIU/ml have no protective effect. . HBsAb levels decrease over time and vary from person to person, which is why the protective effectiveness of the hepatitis B vaccine decreases over time. Therefore, it is possible to periodically measure HBsAb levels for additional hepatitis B vaccination if the HBsAb concentration is < 10 mUI/ml.Although the protective effect of hepatitis B vaccine is very high, it is not 100%. Therefore, a person who has been fully vaccinated against hepatitis B can still be sexually transmitted if the following conditions are also present:
Unprotected sex with someone infected with hepatitis B, risk will be higher if the person infected with hepatitis B is in the stage of viral replication and the virus concentration in the person is high. The anti-HBsAg antibody level in the vaccinated person is low, not effective (HBsAb in the blood). < 10 mIU/ml ) Conclusion: Even though a person has been vaccinated against hepatitis B, other preventive measures are still needed, not subjective. It is necessary to maintain a healthy life, do not have sex without protection measures with a person infected with hepatitis B. If you have unprotected sex with a person infected with hepatitis B, you should immediately go to facilities. medical specialists for examination, consultation and monitoring.
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