Hepatitis

 Hepatitis A virus

Is highly infectious. Spreads by faeco oral route. Poor sanitation aids in its spread. In occasional out breaks water, milk, and shellfish has been the source of spread. In this form a carrier state does not exist. The disease is usually mild as compared to Hepatitis B infection.

Hepatitis B virus

In this type of hepatitis the main source of infection is blood, and the spread my follow transfusion of infected blood or blood products or infection with contaminated needles. Tattooing and acupuncture can also spread this disease. Close personal contacts such as sexual intercourse and especially in the homosexuals is also an important cause of infection. It can be also spread to child from mother at or soon after birth.

Hepatitis B vaccines are available to protect against this infection. This vaccine is ineffective in those already infected with this disease. Vaccination against Hepatitis B forms part of compulsory vaccination of infants in the first year of life. Three doses are needed at 0, 1 and 6 months interval.

Hepatitis B infected individuals carry this infection throughout life. Some are just carriers without having any symptoms of any illness. Some may have acute illness and some develop chronic liver diseases. These persons are at a much high risk of developing Liver cancer in later life.

Delta virus

The delta virus is an RNA containing partial virus which has no independent existence. It requires the hepatitis B virus for replication and has the same source and mode of spread. It causes progressive chronic hepatitis and eventually cirrhosis.

Non-A, Non-B, C and E viruses

Non-A, Non-B and C hepatitis is caused by several viruses. The mode of transmission in humans is similar to those of hepatitis B virus. In developed countries Non-A and Non-B & C hepatitis is now cause of 90 % of the post transfusion hepatitis. It can also be spread by other blood products.

Hepatitis E virus is an entericlly transmitted virus that occurs primarily in India, Asia, Africa, and Central America. This agent has epidemiologic features resembling those of hepatitis A. The virus has been detected in stool, bile, and liver from infected patients as well as from experimentally infected nonhuman primates. Studies in humans and experimental animals have shown that HEV is excreted in the stool during the late incubation period.

The commonly recognized cases occur after contamination of water supplies such as after monsoon flooding. An epidemiologic feature that distinguishes HEV from other enteric agents is the rarity of secondary person-to-person spread from infected persons to their close contacts. In outbreaks of waterborne hepatitis E in India and Asia, the case-fatality rate is 1 to 2 percent and up to 10 to 20 percent in pregnant women. The most feared complication of viral hepatitis is fulminant hepatitis (massive hepatic necrosis).

Hepatitis B Vaccination

Initially the vaccine for active immunisation was prepared from the plasma of healthy HBsAg carriers. The vaccine was subjected to 3 different chemical inactivation steps which cumulatively destroy the infectivity of every known virus without harming the host. The plasma derived vaccine in 1987 was substituted by the genetically engineered vaccine derived from recombinant yeast. This genetically engineered vaccine (Engerix B and Recombivax – HB) consists of HBsAg particles that are non- glycosylated but is otherwise indistinguishable from natural HBsAg. It is equally immunogenic, protective and safe as the first generation plasma-derived vaccine.

Indications for hepatitis B vaccination include pre-exposure and post-exposure cases.

Pre-exposure prophylaxis is advised in the following cases:

• Health workers exposed to blood.
• Haemodialysis patients and staff.
• Intravenous drug abusers.
• Promiscuous homosexual men.
• Promiscuous heterosexuals.
• People requiring repeated blood transfusions.
• Household and sexual contacts of HBsAg carriers.

Pregnancy is not a contraindication for hepatitis B vaccination.

Site of administration:

The vaccination is indicated at 0, 1 and 6 months in the deltoid region or the anterolateral aspect of the thigh and not in the glutial region as it may reduce the efficacy of the vaccine.

Dosage:

1 . Engerix B. (i) 10 micog in children below 10 years; (ii) 20 micog for immunoincompetent children below 10 years; and Adults. (iii) 40 micog for patients on dialysis and other immuno- compromised persons.

2. Recombivax-HB. (i) 2.5 micog for children below 11 years of HBsAg-negative mothers; (ii) 5 micog for infants of HBsAg-positive mothers and children and-adolescents between 11 and 19-yrs; (iii) 10 micg for immunoincompetent adults; and 40 micog for patients on dialysis and other immunocompromised persons.

3. Heppacine-B (plasma derived): 1 ml IM at 0, 1 and 6 months.

For unvaccinated persons sustaining exposure to HBV, treatment comprises:

1. HBIG for immediate action.

2. Hepatitis B vaccination for prolonged action.

Special precautions:

One should be careful during febrile illness infections and in patients on immunosuppressive therapy.

Adverse side effects may include: tenderness and indurations at the site of the injection, fatigue, fever, headache, dizziness and arthralgia.