I. Basic knowledge about hepatitis B surface antigen carriage and its causes
As we all know, China is one of the countries with high prevalence of hepatitis B virus infection, and the survey data on the prevalence of viral hepatitis published in 1997 showed again that the rate of HBsAg carriage in our population is 9.75%, that is, there are hundreds of millions of HBsAg carriers in China. The reason for the formation of HBsAg carriers is mainly related to the body’s low immune function, such as mother-to-child transmission, the infant is infected by a large number of invasive hepatitis B virus (HBV), but lacks the ability to clear the immune, that is, the “immune tolerance state”.
The invasive HBV DNA can integrate with the chromosomal genes of the infant’s liver cells and escape the attack of the body’s immune system, thus manifesting itself as long-term HBsAg carriage. Secondly, infection in infancy, such as infants living in close contact with HBsAg and HBeAg positive mothers, nannies and relatives for a long time, breastfeeding and feeding, deep kissing, etc. can also lead to infection. In addition, infection can also occur through various injection routes (if sterilization is not complete). The chance of becoming a carrier after HBV infection in infancy is about 8 times higher. Adolescents or adults with immunocompromised or low immune function can also become carriers of HBsAg after being infected with HBV.
The serum of HBsAg carriers can detect anti-HBc, HBsAg, HBeAg or anti-HBe and HBV DNA. generally in carriers HBsAg, HBV DNA positive is more contagious, especially more than 90% of such pregnant women can transmit HBV to their newborn babies, called mother-to-child transmission, anti-HBe is not a protective antibody, but when it is positive, the transmission is less likely. Although anti-HBe is not a protective antibody, when it is positive, transmission is less likely.
In recent years, scholars at home and abroad have been committed to research on the control of HBV infection, especially on the treatment of HBsAg carriers, but so far no drugs and methods of special treatment have been found, resulting in people who may carry the virus for a long time with normal liver function.
The development of international hepatitis B vaccine started in 1970, and in China it started in 1973. 1985, the domestic blood-borne hepatitis B vaccine was officially approved for production and use, and so far 100-200 million people have been immunized, and in Beijing, the universal vaccination of newborns with hepatitis B vaccine started in 1988, and the universal vaccination of adolescents started in 1994, and so far more than 1.75 million people have been vaccinated, which has achieved very significant results in reducing the number of new HBsAg carriers. The incidence of hepatitis B among children also dropped from 12.56/100,000 in 1990 to less than 1/100,000; since 1995, genetically engineered hepatitis B vaccine has gradually replaced blood-borne hepatitis B vaccine, At present, more than 400,000 people have been vaccinated in the city, and no significant adverse reactions have been observed, and the effect is better than that of blood-borne vaccine.
HBV transmission route
HBV is present in the blood, body fluids, secretions and excretions of hepatitis B patients and HBsAg carriers. These body fluids containing HBV have different degrees of significance for the transmission of hepatitis B virus.
(i) Perinatal transmission from mother to child
The rate of HBsAg positivity in newborns of HBsAg positive mothers is 10% in Europe and USA, 25-30$in Africa, 30-70% in Asia and about 60% in China.
Almost 100% of babies are transmitted by HBsAg and HBeAg-positive mothers, and 60-90% of them become positive carriers. This route not only has a high transmission rate, and can cause immune tolerance, resulting in lifelong carriage of the virus, is an important reservoir of human HBV hosts and like sources of infection, some of which can develop into liver cirrhosis and liver cancer.
1, HBsAg carriers family members HBsAg positive rate is 10-15 times higher than the control group. And the mother’s HBsAg positivity is the most important, while the father has no significant effect.
2.Mode of mother-to-child transmission
(1) transmission through the placenta: rare, such transmission vaccination can not protect.
(2) Transmission during delivery: Most of the transmission can be due to microscopic fissures in the placenta during delivery, leakage of maternal blood into the fetal blood, or fetal inhalation of amniotic fluid, and infant contact with maternal vaginal secretions.
(3) Transmission after delivery: contact with mother’s saliva and breastfeeding. HBsAg and Dane particles (hepatitis B virus) have been detected in saliva and breast milk, and opinions differ on whether breastfeeding can transmit, but mothers with double positive HBsAg and HBeAg should not breastfeed.
(B) blood transfusion, injection transmission is an important transmission route of HBV
1, blood transfusion and blood products transmission: blood donors HBsAg screening, this route of transmission has been significantly reduced, but the positive rate of patients who have received blood multiple times is significantly higher than the general population.
2, intravenous drug addicts HBsAg positivity is significantly higher than the general population. Needle stick, tattoo, cut and tie, etc. can also cause transmission.
3, other: repeated blood tests, multiple injections, frequent invasive tests and diagnostic measures, etc.
(C) Broken mucous membrane transmission
1, sexual transmission: HBsAg and Dane particles can be found in semen and vaginal secretions, which can be transmitted sexually, so hepatitis B is one of the sexually transmitted diseases.
(1) The rate of HBV infection among domestic sexual abusers is 82.18%, and the rate of HBsAg positivity is 21.78%, which is 4 times higher than the control group.
(2) Serum HBsAg and HBeAg double-positive people, high semen HBV detection rate, spouse HBV infection rate of 66.67%.
(2) Oral mucous membrane breakage can also cause transmission.
Third, on how to correctly or appropriately treat the HBsAg carriers’ practical problems such as enrollment in day care, schooling, employment, marriage and childbirth
HBsAg carriers are different from hepatitis B patients in that they are not patients and do not have clinical symptoms and signs of hepatitis, and the liver function tests are normal. Hepatitis B virus is mainly transmitted through blood, mother-to-child and sexual transmission, not through normal digestive and respiratory transmission, so HBsAg carriers generally do not pose a direct threat to the surrounding population in their daily work, study and social activities. According to the national “viral hepatitis prevention and control program”, HBsAg carriers can work and study as usual, except that they cannot donate blood (including tissues and organs) and engage in contact with directly imported food, utensils and caregiver work, but to strengthen medical observation and follow-up, the following comments are made on the relevant issues.
(A) on employment issues: HBsAg carriers can not engage in contact with directly imported food, tableware catering industry, can not serve as child care institutions nursery staff. It is best not to serve as medical personnel in surgical treatment departments and special military personnel. Other than these other jobs can be normal employment, various departments, industrial and mining enterprises (business), industry, agriculture, commerce, academia and military industries, all types of companies should not refuse to accept these people to work, let alone because of the detection of HBsAg positive and make them laid off or dismissed. In the workplace do not dare to work in the same room, do not dare to sit at the same table, do not want to read a newspaper, documents, do not dare to talk or even distant, discrimination, panic are the lack of awareness of HBsAg carriers and even affect the cause of the development of unnecessary paranoia and behavior. We hope that the whole society should be more understanding and more concerned about the right of HBsAg carriers to participate in work.
(B) on the issue of enrollment: except for those related to catering, conservation or the above-mentioned corresponding professional colleges (technical schools) and special recruits into the military should not apply, HBsAg carriers should enjoy the same opportunities and rights as other students to choose to volunteer and participate in learning.
(C) on the issue of marriage: HBsAg carriers have the right to marry, but in the premarital medical examination should be informed of this situation and related medical knowledge of both parties, premarital examination of their spouses, if the liver function is normal, anti-HBc has been positive, the marriage can be approved immediately, if the hepatitis B virus “two and a half” five full negative, should be injected If the hepatitis B virus “two and a half” five negative, then should be injected with hepatitis B vaccine, to produce protective antibodies before marriage.
(D) on the issue of pregnancy and childbirth: women with HBsAg carriers can be normal and consider childbirth, before medical consultation should be conducted, on the one hand, to assess the physical condition of HBsAg carriers, and at the same time should understand the possible impact on the newborn. Regardless of whether the mother or father carries HBsAg, their newborns must be promptly vaccinated with hepatitis B vaccine within 24 hours of birth and complete the full immunization according to the 0, 1, 6 protocol. For newborns of mothers with double-positive HBsAg and HBeAg, it is best to add hepatitis B high-valent immune globulin within 24 hours after birth (since the production of HBIG is currently suspended, a high-dose hepatitis B vaccine, i.e. 10ug per dose of recombinant yeast hepatitis B vaccine or 30ug per dose of blood-derived vaccine, should be given to such newborns).
(E) On the issue of nursery school admission for young children: Since 1991, the Ministry of Health of China has used hepatitis B vaccine as a planned immunization measure to protect children from hepatitis B. In the past decade, there have long been safety studies reported at home and abroad that HBsAg-positive children no longer pose a risk of transmission to children who have been vaccinated against hepatitis B. Therefore, as long as hepatitis B vaccine is given to children entering nursery school and staff of nursery institutions on a universal basis, HBsAg-positive infants and children should not be denied entry into nursery school.
IV. Some issues that should be noted about HBsAg asymptomatic carriers themselves
(a) from the medical point of view, HBsAg carriers do have some weaknesses in the body in the immune mechanism for the removal of HBV, they should be under regular medical observation, in life should avoid overwork, pay attention to the combination of work and rest, maintain a happy mood, improve personal hygiene, consciously prevent their own blood, saliva, urine and other body fluids secretions contamination of the surrounding environment; use and keep the personal utensils HBsAg carriers should also pay attention to the protection of the liver, prohibit alcohol, prohibit the use of drugs that damage the liver, pay attention to the prevention and treatment of other diseases, especially infectious diseases, to avoid further damage to the liver.
(2) In terms of medical observation and follow-up, follow-up examinations should be conducted every six months to a year, and medical attention should be sought at any time when abnormalities are detected. The follow-up examination should include physical examination, liver function, serum HBV infection indication and B-type ultrasound examination of liver, and serum fetoprotein should be tested for those over 40 years old in order to detect changes in condition and take corresponding treatment measures.
V. Key targets of hepatitis B vaccination
In addition to universal hepatitis B vaccination for newborns and preschool children, the following groups of people should also be the key targets.
(a) Spouses of HBsAg carriers, close contacts within the family of hepatitis B patients or HBsAg carriers, and those who are susceptible to hepatitis B virus (HBsAg, anti-HBc and anti-HBs are negative, or anti-HBsP/N<10) when one of them is positive for HBsAg in premarital examination, should be vaccinated with high doses according to the 0, 1, 6 months (or 0, 1, 2 months) program. Hepatitis B vaccine (dose as before).
(b) Prevention of medical and health personnel: Medical personnel are often in contact with a large number of hepatitis B carriers, and inevitably come into contact with the blood and other secretions of positive patients during surgery, injection, nursing, laboratory tests and examinations, so the chance of infection with hepatitis B virus increases relatively. All susceptible persons among these people should be vaccinated with high-dose hepatitis B vaccine according to the 0, 1 and 6 months procedures (dose as before).
(iii) In order to interrupt the horizontal transmission of hepatitis B virus among adolescents in elementary school students and colleges, the military, and athletes, and to protect adolescent health, these populations should be vaccinated according to the 0, 1, and 6 month procedures by giving 10-5-5 μg of recombinant yeast hepatitis B vaccine, respectively, or 30-10-10 μg with blood-derived vaccine, respectively.
(iv) Other populations: renal dialysis patients, homosexuals, intravenous drug addicts, professional donors, blood recipients and organ transplant recipients can be vaccinated with high-dose hepatitis B vaccine (at the same dose as before) according to the 0, 1, and 2 month procedures before surgery.
The management of HBsAg carriers involves all aspects and touches thousands of families, so it must be taken seriously.