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Hepatitis - Prevention and Management
 

Hepatitis - Prevention and Management

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Hepatitis Prevention And Management

Hepatitis Prevention And Management

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    Hepatitis - Prevention and Management Hepatitis - Prevention and Management Presentation Transcript

    • Viral Hepatitis – Prevention & Management DR ARIF ISMAIL DEPARTMENT OF ORTHODONTICS
    • Introduction Viral Hepatitis may be defined as infection of the liver caused by any of half dozen viruses. Twenty years ago hepatitis A virus (HAV) and hepatitis B virus (HBV) were the only known aetiological agents of viral hepatitis. Today, in addition to HAV and HBV hepatitis viruses C,D,E and G have also been identified and are recognized as aetiological agents of viral hepatitis.
    • Hepatitis A Prevention and containment : a) Control of reservoir : Control of reservoir is difficult because of the following factors : (a) faecal shedding of the virus is at its height during the incubation period and early phase of illness (b) the occurrence of large number of sub-clinical cases (c) absence of specific treatment and (d) low socio-economic profile of the population usually involved.
    • b) Control of transmission : The best means of reducing the spread of infection is by promoting simple measures of personal and community hygiene e.g., hand-washing after eating and after toilet ; the sanitary disposal of excreta which will prevent contamination of water , food and milk ; and purification of community water supplies by flocculation, filtration and adequate chlorination. Studies indicated that 1mg/L of free residual chlorine can cause destruction of the virus in 30 minutes at
    • PH values of 8.5 or less. Other control measures include proper autoclaving of syringes, needles and other equipment. If all these measures are properly implemented, a substantial reduction of HAV infection can be expected. c. Control of susceptible population : Human Immunoglobulin : A well established procedure is the use of normal human immunoglobulin prepared from pooled plasma of healthy donors (gamma globulin) to induce passive immunity. It is recommended for (a) susceptible persons traveling to highly endemic areas (b) close personal contacts of persons with HAV, and (c) for the control of outbreaks in institutions.
    • Doses of Immunoglobulin recommended by WHO Agent/ Condition Target Population Preparation Dose Status Hepatitis A Family contacts; Institutional Outbreaks IG (0.02 ml/kg bd. wt.) Recommended for prevention Travelers exposed to unhygienic conditions in tropical or developing countries IG (0.02-0.05ml/kg bd. wt.) Recommended for prevention
    • Vaccines : Several inactivated or live attenuated vaccines against hepatitis A have been developed, but only 4 inactivated hepatitis A vaccines are currently available internationally. All 4 vaccines are similar in terms of efficacy and side effect profile. The vaccines are given parenterally, as a 2 – dose series, 6 to 18 months apart. The dose of vaccine, vaccination schedule, age for which the vaccine is licensed, varies from manufacturer to manufacturer.
    • No vaccine is licensed for children aged less than one year. A combination vaccine containing inactivated hepatitis A and recombinant hepatitis B vaccines has been licensed since 1996 for use in children aged 1 year or older in several countries. The combination vaccine is given as a 3 – dose series, using a 0, 1, 6 months schedule.
    • Hepatitis B Since there is no specific treatment, prevention has been the major aim in managing viral hepatitis B. The following measures are available. a. Hepatitis B vaccine 1) PLASMA DERIVED VACCINE : This is based on the surface antigen (HBsAg) which is harvested and purified from the plasma of human carriers of hepatitis B virus. The final vaccine is a formalin inactivated sub-unit viral vaccine for
    • intramuscular injection. Each 1 ml dose of the vaccine contains 20 micrograms of hepatitis surface antigen formulated in an alum adjuvant. 2) RDNA-YEAST DERIVED VACCINE : An alternate vaccine against hepatitis B has been licensed for the first time in USA in 1987, the recombinant DNA vaccine elaborated from cultures of yeast cloned with HBsAg s-gene. Several field trials have shown that this genetically engineered vaccine is as immunogenic, safe and effective as the plasma derived vaccine. The fact that this vaccine does not depend on
    • on the scarce plasma resource is an added advantage. The dose for adults is 10-20 micrograms initially (depending on the formulation) and again at 1 and 6 months. Children under 10 years of age should be given half of the adult dose at the same intervals. For greatest reliability of absorption, the deltoid muscle is preferred for injection as gluteal injection often results in deposition of vaccine in fat rather than muscle, with fewer serologic conversion. For infants and children under 2 years, anterolateral aspect of thigh is
    • used as vaccination site. Intradermal administration is not recommended because the immune response is less reliable particularly in children. The hepatitis B vaccine does not interfere with immune response to any other vaccine and vice-versa. The birth dose of hepatitis B can be given safely together with BCG vaccine. However, the vaccines should be given at different sites.
    • b. Hepatitis B Immunoglobulin (HBIG) : For immediate protection, HBIG is used for those acutely exposed to HBsAg-positive blood, for example (a) surgeons, nurses or laboratory workers (b) newborn infants of carrier mothers, and (c) sexual contacts of acute hepatitis B patients. The HBIG should be given as soon as possible after an accidental inoculation (ideally within 6 hours and preferably not later than 48 hours). At the same time the victims blood is drawn for HBsAg testing. If the test is negative, vaccination should be started immediately and a full course given. If the test is positive for surface antibody, no further action is needed.
    • The recommended dose is 0.05 to 0.07 ml/kg of body weight ; two doses should be given 30 days apart. HBIG provides short-term passive protection which lasts approximately 3 months. Since the median incubation period is said to be lower than 100 days, two doses of HBIG given one month apart should suffice. The general use of HBIG for long-term prophylaxis has not been recommended because of its limited availability, its high cost and risk (although remote) of complications through repeated use over a long period of time.
    • Hepatitis C Interferon is the only drug that has been found effective in the treatment of HCV infection. However, treatment is very expensive - thousands of dollars for the drug alone - and must be administered by injection several times a week for several months. Moreover, some patients, experience serious sideeffects. Also, about half of the patients go into remission, but 50 % relapse when the treatment is stopped ; only 25 % have long term remission. Given its cost, only a minority of patients can afford it, or are likely to be offered. Studies involving less costly, orally administered drugs are continuing, but results so far
    • have been disappointing. For a number of technical reasons, the development of a vaccine to prevent HCV infection is unlikely for many years. Hepatitis E There is no specific treatment for hepatitis E. Only supportive measures are required. Recovery from hepatitis E is always complete. No vaccine or specific immunoglobulin prophylaxis is available. Preliminary studies in primates indicate that protection through vaccination may be achievable in the foreseeable future.
    • Delta Hepatitis Delta hepatitis infection always occurs in association with hepatitis B (carrier state). The mode of transmission of this infection, its prevention and control are identical to those for hepatitis B. Immunization against hepatitis B also protects against delta infection. Delta hepatitis has not been reported as significant in India. Hepatitis G Hepatitis G virus HGV was discovered recently in 1996. The prevalence of this infection is still not known. A few publications provide information on the association of this infection with blood transfusion in India.
    • Thank You