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The Use and Efficacy of Hepatitis Vaccines

The Use and Efficacy of Hepatitis Vaccines. Hala Alhasan Aneri Gandhi Saba Chowdhry Hyo Won Ahn. PHM142 Fall 2013 Coordinator: Dr. Jeffrey Henderson Instructor: Dr. David Hampson. What is Hepatitis?.

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The Use and Efficacy of Hepatitis Vaccines

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  1. The Use and Efficacy of Hepatitis Vaccines HalaAlhasan Aneri Gandhi Saba Chowdhry Hyo Won Ahn PHM142 Fall 2013 Coordinator: Dr. Jeffrey Henderson Instructor: Dr. David Hampson

  2. What is Hepatitis? • Hepatitis is an inflammation of the liver mostly caused by viral infection. However, heavy alcohol use, toxins, some medications and certain medical conditions can also cause hepatitis. • There are several types of hepatitis, each named from its virus: Hepatitis A, B, C, D, E, G and X. • The most common types of viral hepatitis in Canada are hepatitis A, B and C. • Hepatitis may start and get better quickly (acute hepatitis), or cause long-term disease (chronic hepatitis). In certain cases, it could lead to liver damage, liver failure, or even liver cancer.

  3. Causes • Hepatitis A virus spreads through contact with food or water contaminated with the virus. • Hepatitis B virus spreads through contact with contaminated blood and also sexually transmitted. • Hepatitis C virus spreads through contact with contaminated blood or blood products. • Hepatitis D virus spreads through contact with contaminated blood. It usually only occurs in people already infected with hepatitis B virus. • Hepatitis E virus spreadsthrough contaminated water or food. It is common in developing countries.

  4. How can you tell? • Hepatitis A-E • Abdominal pain due to enlarged and tender liver • Fluid in the abdomen (ascites) • Yellowing of the skin (jaundice) • Loss of appetite, nausea and vomiting • Dark urine • Hepatitis G • No symptom (Source: Palm Partners Recovery Center) (Source: Immunization Action Coalition)

  5. Treatments • Bed rest, abstaining from alcohol, and taking medication to help relieve symptoms. Most people who have hepatitis A and E get well on their own after a few weeks. • Hepatitis B is treated with drugs, such as peginterferon, Epivir, Hepsera, Baraclude, Tyzeka, and tenofovi. • Hepatitis C is treated with a combination of peginterferonand ribavirin. • No effective treatment for hepatitis D or E.

  6. Vaccines • Only hepatitis A, B and D have vaccines available. • Hepatitis C and E have no vaccine.

  7. Hepatitis A

  8. What is Hepatitis A? • Disease of the liver • Caused by Hepatitis A Virus (HAV) • Severity varies from person to person: • Mild • Severe • Very severe (rare)

  9. HAV • Non-enveloped • Replicated in cytoplasm • Single-stranded RNA

  10. Pathogenesis

  11. How to test for Hep A • Blood test • IgM Hep A antibodies (Anti-HAV IgM) present = recent infection • IgG Hep A antibodies (Anti-HAV IgG) present = previous infection and immunity against Hep A • Liver function test • High serum albumin levels = infection • High serum aminotransferase levels = infection

  12. Prevention • Hepatitis A Vaccination • Invented by Maurice Hilleman • Brand names (Canada): Avaxim, Havrix, Vaqta • 2-dose in Canada • Vaccination • Booster • Inactivated virus • Protection starts after 2-3 weeks Efficacy • HAVRIX and VAQTA

  13. Double dose vaccine 2nd dose given after at least 6 mos

  14. Who should get the vaccine? • Children over 1 yrs • Hep A lab workers • People travelling to areas with high incidence of Hep A • Chronic liver disease patients • Drug-abusers

  15. Hepatitis B

  16. Hepatitis B • 500,000 deaths each year • Transmission: blood, serum, plasma, • saliva, semen, tears, breast milk

  17. Hepatitis B Vaccine • Reduces the incidence of Hep B • Injectable Vaccine for Active Immunization Against Infection • Recombinant DNA technology, produced in yeast cells • Injected intramuscularly Tana et al, 2009

  18. Hepatitis B Vaccine • Engerix®-B • 3 doses: administered at 0, 1 and 6 months • Recombivax HB® • 3 dose regimen: 1st injection, 2nd ≥1 month, 3rd ≥1 months after 2nd • 2 dose regimen: 1st dose, 2nd dose: 4 to 6 months after 1st • Vaccination is strongly recommended in subjects who are at increased risk • Health professionals, patients, travellers

  19. Efficacy of Hepatitis B Vaccine • Goal: to eliminate hepatitis B • Effective in protecting for at least 15 years • Anti-HBs titre greater than 10 IU/L correlates with protection • > 90% of healthy adults, children developed protective one month after completing a primary vaccination schedule • Larger vaccine doses or an increased number of doses are required • hemodialysis patients • immunocompromised patients

  20. Hepatitis D

  21. What is Hepatitis D? • RNA virus • Circular or linear RNA genome • Surrounded by nucleocapsid protein • Also surrounded by envelope that has Hep B antigens • Caused by Hepatitis D virus (HDV) • Subviral satellite • Requires HBV as a helper virus

  22. Types of infection • Co-infection • Person is affected by Hep B and Hep D at the same time • Likely to cause acute liver failure • Super-infection • Person is affected by Hep B first, followed by Hep D • Likely to cause cirrhosis

  23. Mode of Action • receptor that HDV recognizes on hepatocytes has not been recognized • Thought to be the same as the HBV receptor • Recognizes receptor via N-terminal domain of the Hep B surface antigen (HBsAg) • After entering, virus is uncoated and nucleocapsid relocates to nucleus • Virus uses the hepatocyte’s RNA polymerases to replicate its genome

  24. http://www.nature.com/nrgastro/journal/vaop/ncurrent/fig_tab/nrgastro.2013.164_F2.htmlhttp://www.nature.com/nrgastro/journal/vaop/ncurrent/fig_tab/nrgastro.2013.164_F2.html

  25. Prevention/treatment • There is NO vaccine for Hepatitis D • should get Hepatitis B vaccine • No effective antiviral treatment • Can only reduce risk behaviours • i.e. Don’t share needles

  26. Summary Slide • Hepatitis is an inflammation of the liver mostly caused by viral infection, hepatitis A, B and C being most common in Canada. • Hepatitis Viruses spread through contaminated food, water or blood – Hep B can spread sexually. • People with hepatitis A and E get well after a few weeks but hepatitis B and C are treated with drugs. • Only hepatitis A, B and D have vaccines available. • Hepatitis A – caused by Hep A Virus (HAV) • Tested for by: 1) Blood test or 2) Liver Function Test • No treatment available • HAV Vaccination: • Brand names in Canada include: Avaxim, Havrix, Vaqta • 2-dose in Canada (Vaccination + Booster) • Inactivated virus – Body produces antibodies against HAV • Hepatitis B Vaccine • Brand Name: Engerix®-B, Recombivax HB® • Anti-HBs titre greater than 10 IU/L correlates with protection • Effective in protecting for at least 15 years • Hepatitis D • Subviral satellite- relies on Hepatitis B for infection • No vaccine available

  27. References • Bader, T. F. "Hepatitis A vaccine." The American journal of gastroenterology91.2 (1996): 217. • Tong, M. J. "Hepatitis A vaccination." Western journal of medicine 158.6 (1993): 602. • Hepatitis A. World Health Organization, Jul. 2013. Web. 9 Nov. 2013. • Hepatitis A Information for Health Professionals. Centers for Disease Control and Prevention, 1 Apr. 2008. Web. 9 Nov. 2013. • Hepatitis A Overview. Medscape Multispecialty, n.d. Web. 9 Nov. 2013. • Mandell, G.L., Bennett, J.E., Dolin, R. (2010). Principles and Practice of Infectious Diseases Seventh Edition. Philadelphia, PA: Elsevier Inc. • M Tana, K Hoda, J Wong, and others. HBV Screening in Asian Pacific Islander Americans: An Interim Analysis of the Hep B Free Program. Digestive Disease Week (DDW 2009). Chicago. May 30-June 4, 2009. Abstract W1811 • Compendium of Pharmaceuticals and Specialties, online version (e-CPS). Canadian Pharmacists Association, 2013

  28. References contd… • Fitzsimons, D., Bocher, W., Jilg, W., Duval, B., Zanetti, A., Meheus, A., et al. (2005). Long-term Efficacy Of Hepatitis B Vaccine, Booster Policy, And Impact Of Hepatitis B Virus Mutants. Vaccine, 23(32), 4158-4166. • Niro, G. A., F. Rosina, and M. Rizzetto. "Treatment of hepatitis D." Journal of viral hepatitis 12.1 (2005): 2-9. • Lavanchy, Daniel. "Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures." Journal of viral hepatitis 11.2 (2004): 97-107. • Jacobson, Ira M., et al. "Epidemiology and clinical impact of hepatitis D virus (delta) infection." Hepatology 5.2 (1985): 188-191. A.D.A.M. Medical Encyclopedia. (2011). Hepatitis. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002139/ • Centers for Disease Control and Prevention. (2008).Hepatitis Information for the Public. Retrieved from http://www.cdc.gov/hepatitis/PublicInfo.htm#whatIsHep • NIH MedlinePlus magazine. (2009). Hepatitis: Symptoms, Diagnosis, Treatment & Prevention. Volume 4: 25. • Nordqvist, C. (2009).What Is Hepatitis? Symptoms, Causes and Treatments. Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/145869.php • Public Health Agency of Canada. (2012). Hepatitis. Retrieved from http://www.phac-aspc.gc.ca/hep/index-eng.php

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