Hepatitis B

Hepatitis B is a liver disease caused by infection in relation to hepatitis B virus (HBV). About 20,000 people are infected by Hepatitis B annually. It is a highly infectious virus, and the infection can be transferred to a child at the time of birth if the mother is infected with hepatitis B. Other methods of transmitting the disease include, blood transfusion of a father, family, friends, virus-contaminated blood or sexual activity Infections (horizontal infection).However, in the case of children, the cause of infection is often unknown. In Southeast Asia, it is said that after 5% of the Vietnamese population is infected, about 5 million Thai people, about 8% of the population are infected.
When adults are infected with hepatitis B for the first time, most of them will heal with a transient infection and acquire immunity. Many people who have been transiently infected with hepatitis B will heal with no subjective symptoms and some will develop acute hepatitis resistence.

When infected with hepatitis B virus at birth or infancy and become a hepatitis B virus carrier (sustained holder), many of them do not develop hepatitis until a certain time and remain healthy. However, most hepatitis B virus carriers develop hepatitis from the age of 10 to the age of 30.

Source of hepatitis B Virus Infection

Hepatitis B virus can infect the blood and through other bodily fluids. The risk of infection increases in the following cases.

・When sharing syringes with other people and injecting stimulants or narcotics.

・When piercing, tattooing, etc. are performed using equipment not properly disinfected.

・In case of infection via sexual activity

・You did not take appropriate preventive measures against a child born of a mother infected with hepatitis B.

Hygiene has vastly improved in the medical field in Japan, and there has been counter measures in place in order to prevent mother-to-child infection of Hepatitus B virus. Now you rarely see this type of infection since 1986.

In contemporary Japan, infection caused by sexual activity is the only route of infection that modern medicine is having trouble preventing.However, there are still a large number of people infected with hepatitis B in South east asia and east asia. It is said that there are 400 million people infected with Hepatitis B all over the world. Southeast Asia and East Asia have about 300 million people who are infected.

Treatment and prevention of hepatitis B virus

Symptoms such as nausea may appear following general malaise when infecting with hepatitis B virus for the first time. There are some who experience symptoms such as dull pain on the right back as the liver grows swollen. However, even when infected with hepatitis B virus for the first time, there is no subjective and residual symptoms and the virus may be completely eradicated from the body. A full recovery is expected.

Hepatitis B virus is examined by blood test. First, we test HBs antigen, but if HBs antigen is detected, it means that hepatitis B virus is growing in the liver of the person and that there is a virus in the blood. As a method of investigating the amount of hepatitis B virus, we use nucleic acid amplification test to amplify and detect a portion of the hepatitis B virus gene.

The vaccine used in Japan and abroad differs in terms of the hepatitis B Vaccine.

■Vaccines in Japan

・Number of inoculations: 3 times in total

・Inoculation frequency: first time, 4 weeks, after 5 to 6 months

・Antibody duration: 5 years (after 3 inoculations)

・Frequently used vaccines:

 1. BeamGen (Manufacturing: Chem., Selling agency: Astellas Pharma)

 2. Heptavax (Manufacturing: Merck, USA, distributor: MSD Co., Ltd.)

 ※The number of vaccinations, vaccination interval, expected immunity duration are the same.

■Vaccine in Thailand

・Number of inoculations: 3 times in total

・Inoculation frequency: First time, 4 weeks, 6 months

・Antibody duration: 15 to 20 years

・Frequently used vaccines: Engerix B (Glaxo Smith Klone)

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・The number of inoculations and the schedule are the same.

Chronicity of Hepatitis B

Chronic hepatitis B is a disease caused by the persistence of hepatitis B virus (HBV) infection.Although HBV is infected by blood infection and sexual intercourse, most cases of persistent infections (carriers) are infected early in life. The main infection route is infection (mother-to-child transmission or vertical infection) to children born from mothers of HBV carriers.

 When infected after a certain age, acute hepatitis develops but infection in Japan has been transient and rarely chronic. However, in recent years, acute hepatitis due to many virus genotypes (genotype A) in Europe and the United States is increasing, and the number of cases where infection becomes prolonged and becomes chronic after a increase in community infection

 Infected HBV proliferates in the liver, but basically the virus itself does not have negative effects on hepatocytes. Therefore, in the early childhood when the immune ability is underdeveloped, it progresses as an asymptomatic carrier without causing hepatitis After that, when it comes to post puberty, an immune reaction trying to eliminate the virus from the body occurs, causing hepatitis. In many cases, the symptoms of hepatitis are also light, liver disorder does not progress much, but about 10 to 20% of HBV carrier shifts to chronic hepatitis (a state where hepatitis continues for more than 6 months), and further chronic hepatitis and may progress to liver cirrhosis and liver cancer.

What kind of people are carrying Hepatitis B

A state in which the hepatitis B virus can not be excluded from the body and continuously stays within their body throughout their life is called persistent infection.A typical example is when infants are infected by mothers during childbirth. Those who are persistently infected with hepatitis B virus are sometimes referred to as Hepatitis B virus (HBV) carriers, asymptomatic carriers or persons with hepatitis B virus with a persistent infection.

When an adult is infected with hepatitis B virus, immunity is already developed, so most of it is healed before the person is aware of it. When the body’s immune power is remarkably lowered (When it is infected with AIDS virus etc.) or infection with hepatitis B virus of a specific alien species, there is a possibility of persistent infection even if infected after becoming adult.

Concerning Hepatitis A & B Hepatitis Combination Vaccine

Although unapproved in Japan, Twinrix which is widely used abroad will be recommended. Twinrix is a vaccine manufactured by Glaxo Smith Kline and is a combination vaccine of hepatitis A and hepatitis B.

■Details of Hepatitis A & B Hepatitis Combination Vaccine (Twinrix)

・Number of inoculations: 3 times in total

・Inoculation frequency: First time, 4 weeks, 6 months

・Antibody duration: 15 to 20 years