Hepatitis B - Transmission And Prevention

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Hepatitis B - Transmission And Prevention
Hepatitis B - Transmission And Prevention
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Video: Hepatitis B Dispelling Myths and Misconceptions - Focus on Transmission & Prevention 2023, February
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Hepatitis B: Transmission & Prevention

Hepatitis B is a reportable viral disease that is associated with inflammation of the liver. An acute infection can develop into a chronic form. The viruses are mainly transmitted via unprotected sexual intercourse or blood. Two billion people are considered infected or have had hepatitis B infection. The WHO currently estimates the number of people infected at around 257 million and the number of deaths from consequences of a hepatitis B virus infection at around 887,000 people annually. This makes hepatitis B the fourth most common infection-related cause of death worldwide. Fortunately, these numbers are continuously improving because many countries have initiated hepatitis B vaccination programs. The long-term goal of the WHO is to eradicate hepatitis B through vaccination.

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  • Spread of hepatitis B infections
  • How are hepatitis B viruses transmitted?
  • How does hepatitis B work?
  • How can you prevent hepatitis B infection?

Spread of hepatitis B infections

Antibodies against hepatitis B viruses (HBV) can be detected in five to ten percent of the general population in Central Europe, and around one percent is infected (HBs-Ag positive). In Austria about 1.2 percent of the population are infected. In this country, the reported hepatitis B cases have increased in recent years. Increasingly, migrants from high-endemic areas (areas with a particularly high number of sick people) represent the major proportion of chronic hepatitis B virus carriers in Western countries with low HBV incidence. A distinction is made between different hepatitis B virus genotypes (A – J). Genotypes are “groups of viruses” that differ in their genetic material. The hepatitis B genotypes show a different geographical distribution.They are decisive for the course of the disease and the choice of therapy. In Europe, the genotypes A, D and G are mainly found. Due to migration and globalization, however, other genotypes can always be detected.

Hepatitis B in Austria

About 1.2 percent of the population are chronically infected. Between 2009 and 2016, an average of around 790 hepatitis B cases were reported each year. In 2017, 1,221 hepatitis B infections were reported. Reports without a doctor's report (132 cases) may not be newly diagnosed cases.

How are hepatitis B viruses transmitted?

The typical transmission route in adulthood is sexual contact. Even the smallest skin and mucous membrane injuries (blood contact) are sufficient for an infection. Sperm, vaginal secretions, saliva and tears from people infected with hepatitis B are also infectious.

A transmission of hepatitis B viruses is possible, for example:

  • if the sexual partner has hepatitis B,
  • through "needle sharing" (shared use of needles, syringes, filters and spoons among drug addicts) or shared use of the "tube" - rolled up paper or money - to sniff cocaine through the nose),
  • from a needlestick injury if a person infected with hepatitis B is involved,
  • at birth to the newborn if the mother has hepatitis B.

Additional possibilities of infection arise through sharing a toothbrush, razor, nail scissors or nail file with a person suffering from hepatitis B or through tattoos and piercings under unsanitary conditions. There are also - extremely rarely - so-called nosocomial transfer cases. The transmission in health facilities takes place via infected people working in the medical field or non-sterile - i.e. not sufficiently cleaned - medical instruments. With the general testing of blood products and other blood products for markers of HBV infection, the occurrence of transfusion-related hepatitis B (eg in the case of hemophilia) in industrialized countries can now be almost completely ruled out. However, it is fearedthat not all blood donations are adequately screened for HBV in developing countries.

The following are particularly at increased risk of contracting the hepatitis B virus:

  • Drug users with the above-mentioned behavior,
  • People who live with someone infected with HBV,
  • People with frequently changing sexual partners (e.g. prostitutes),
  • homosexual men,
  • HIV-infected people,
  • Salaried employees and trainees in health and care professions,
  • People at risk of infection through blood contact with potentially infected people (e.g. first aider, police officers) and
  • Travelers to areas with high levels of HBV and close contact with the local population.

Note There is no risk of the transmission of hepatitis B viruses through social contacts such as shaking hands, hugging, kissing on the cheek, eating, drinking and using the same toilet.

How does hepatitis B work?

The incubation period for hepatitis B is 45 to 180 days (usually around 60 to 120 days). An acute hepatitis B infection can be asymptomatic (without symptoms) to fulminant. A brilliant course only develops in 0.5 to one percent of those infected. This leads to massive liver cell damage and, within a short time, to complete destruction of the organ. Without a liver transplant, this form of disease is fatal in up to 80 percent of cases.

If the immune system cannot fight the hepatitis B virus sufficiently within six months, chronic hepatitis B will develop.

The course of a hepatitis B infection depends primarily on the age of the person affected at the time of infection or illness and probably on the genotype. If the infection is transmitted from mother to child during childbirth, the infection becomes chronic in up to 90 percent of cases. This is the most common route of transmission in countries with high incidence of hepatitis B. If infected up to the age of six, the risk of a chronic course is 30 to 50 percent. If the disease occurs in adulthood, only five to ten percent of infections develop into a chronic course. The influence of genotypes on the course of the disease has not yet been studied in detail. Most of the studies come from Asian countries.Therefore, the results cannot be fully transferred to disease courses in Europe. Compared to genotypes C and D, those infected with genotype A may have a lower spontaneous healing rate. Cirrhosis of the liver appears to develop more slowly in infections with genotype B than in infections with genotype C.

Cirrhosis of the liver and hepatocellular carcinoma (liver cancer) are possible consequences of long-term chronic hepatitis B infection.

A simultaneous (co-infection) or subsequent (superinfection) infection with the hepatitis D virus usually results in more severe clinical pictures. The co-infection leads to fulminant courses, but only about five percent of the cases develop a chronic course of hepatitis B or D. The destruction of the liver tissue with the formation of liver cirrhosis progresses faster in the chronic course. In addition, liver cell carcinoma (liver cancer) develops more frequently and more quickly.

Note It is possible for the hepatitis B virus to smuggle part of its genetic material (cccDNA) into the cell nucleus. There it is safe from the immune system. If the immune system is severely weakened - for example by immunosuppressive therapy - it can leave the cell nucleus again and hepatitis B breaks out again. This is usually very aggressive.

How can you prevent hepatitis B infection?

Reliable protection against hepatitis B is achieved through:

  • the active vaccination (dead vaccine),
  • Safe sex (condoms!),
  • Avoidance of blood contact (e.g. by wearing disposable gloves),
  • sterile execution of tattoos and piercings,
  • sole use of toothbrushes, razor blades, needles or syringes (no “needle sharing”!).

Vaccination

According to the WHO, the hepatitis B vaccination is recommended for every adult and is particularly suitable for people with chronic liver disease and people who frequently need plasma products (e.g. haemophiles), predialysis (patients who are likely to need dialysis) and dialysis patients / Patients important.

Basic immunization

The basic immunization represents the development of a vaccination protection. With the active vaccination against hepatitis B there are usually three stab injections in the upper arm:

  • The first vaccination counts as day one,
  • the second vaccination follows about a month later,
  • the third vaccination again six to twelve months later.

If faster vaccination protection is needed, three vaccinations can be given within a shorter period of time and then a fourth vaccination after twelve months. A combination of a hepatitis B vaccine and a hepatitis A vaccine is also available.

A combination vaccine with diphtheria / tetanus / whooping cough / polio and Haemophilus influenzae B is provided for children as part of the Austrian vaccination plan. In this case, the vaccination schedule is different from that for adults. The cost of vaccinating children is covered by social security. The corresponding measures are noted in the mother-child pass.

Booster vaccination and control of vaccination protection

If the primary immunization was given in childhood, a booster between the ages of seven and 15 is recommended. After this booster vaccination and with primary immunization in adulthood, titer control (determination of the amount of HBs antibodies in the blood) is only generally recommended for people who belong to a risk group. However, anyone who wants to be informed about their vaccination protection can have a titre control carried out at their own expense. If the vaccination protection is insufficient, a booster vaccination must be administered.

People who respond to the vaccination have almost 100 percent vaccination protection. However, vaccination failures can occur. Whether a hepatitis B vaccination was successful can be checked by determining the titer. The vaccination is generally well tolerated.

Post exposure prophylaxis

The transmission of hepatitis B can be avoided within the first few days after contact with the virus if an active and passive (immunoglobulin) vaccination is given. This so-called post-exposure prophylaxis should take place as early as possible - preferably within three days to a week at the latest - after a risk contact. Passive immune prophylaxis - together with active vaccination - is also recommended for all newborns of infected (HBs antigen-positive) mothers within twelve hours of birth in order to prevent the transmission of HBV infection.

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