Hepatitis A
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Hepatitis A

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epidemiology and control

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  • Still, manufacturers recommend two vaccine doses to ensure a longer-term protection of about five to eight years after vaccination. <br />
  • Differences in exposure may be due to the levels of socio-economic status of the family and stage of development of the place of residence <br />

Hepatitis A Hepatitis A Presentation Transcript

  • Hepatitis A Virus Dr. Priyamadhaba Behera 1
  • Hepatitis A Virus World Hepatitis Day on July 28 every year to increase awareness and understanding of viral hepatitis References WHO Document, 5th edition OTPH, 18th edition Harrison principle of medicine, Articles however applicable
  • Introduction • Picornavirus (RNA) • Humans are only natural host • Stable at low pH • Inactivated by high temperature, formalin, chlorine, boiling point for 1 minute 3
  • Introduction •Naked RNA virus •Related to enteroviruses,formerly known-enterovirus 72
  • Introduction • One stable serotype only • 4 genotypes • Globally, there are an estimated 1.4 million cases of hepatitis A every year • Hepatitis A infection does not cause chronic liver disease and is rarely fatal, but it can cause debilitating symptoms and fulminant hepatitis (acute liver failure) 5
  • Epidemiology
  • Country Citation Epidemiology-India Year Seroprevalence Sample Population / Size Comments
  • Epidemiology-India
  • Transmission • Primarily -faecal-oral route • Waterborne outbreaks (infrequent) are usually associated with sewage-contaminated or inadequately treated water • Close physical contact with an infectious person not casual contact among people
  • Risk factors • • • • • Poor sanitation Lack of safe water Injecting drugs Living in a household with an infected person Being a sexual partner of someone with acute hepatitis A infection • Travelling to areas of high endemicity without being immunized
  • Signs and Symptoms • Hepatitis A infection has four clinical phases, although these do not occur in all patients • First stage  An incubation period of 15 to 50 days (mean 28 to 30 days)  Asymptomatic  Infected person may be actively shedding the virus in the stool
  • Signs and Symptoms Second stage (pre-icteric ) • Several days to weeks that may precede the onset of jaundice. • Prodromal period is characterized by nonspecific symptoms • Followed by gastrointestinal symptoms such as anorexia, nausea, vomiting, abdominal pain, fatigue, malaise, and fever. • Myalgia, arthralgia , cough, pharyngitis, constipation, diarrhea, pruritus, and urticaria. Dark urine caused by elevated bilirubin levels usually occurs prior the onset of jaundice.
  • Signs and Symptoms Third stage • Characteristic yellowing of the skin and eyes of jaundice appear • Most symptoms subside • Clinical signs such as hepatomegaly and hepatic tenderness are found in about half of patients • There is no treatment for HAV infection. Jaundice usually resolves within a few weeks Final stage • Convalescent period during which the patient recovers
  • COMPLICATIONS • The vast majority of hepatitis A patients make a full recovery, and the case fatality rate is low. The estimated mortality rate is 0.1% for children less than 15 years old, 0.3% for adults ages 15 to 39, and 2.1% for adults ages 40 and old [hollinger, 1996] • About 15% of patients experience prolonged jaundice and/or relapses over several months. Some develop cholestatic hepatitis • Fulminant (acute) liver failure -chronic liver disease prior to onset of disease
  • Laboratory Diagnosis
  • Prevention • Improved sanitation • Food safety • Immunization Spread of hepatitis A can be reduced by • Adequate supplies of safe drinking water • Proper disposal of sewage within communities • Personal hygiene practices such as regular hand-washing with safe water
  • Hepatitis A vaccine • Several hepatitis A vaccines are available internationally (similar in terms protection and their side-effects) • No vaccine is licensed for children younger than one year of age • Nearly 100% of people develop protective levels of antibodies to the virus within one month after a single dose of the vaccine
  • Hepatitis A vaccine • After exposure to the virus, a single dose of the vaccine within two weeks of contact with the virus has protective effects • No serious adverse events • Can be given as part of regular childhood immunizations programmes, eg (argentina, china, israel and the united states of america have) • For travellers to endemic areas
  • Hepatitis A vaccine The vaccine for people at increased risk of hepatitis A • Travellers to countries where the virus is endemic • Men who have sex with men • People with chronic liver disease (because of their increased risk of serious complications if they acquire hepatitis A infection)
  • Hepatitis A vaccination-India • • • • • At present there is lack of evidence for recommending universal vaccination against hepatitis A in India1 Data from india indicate that the population is no longer homogeneous for HAV exposure profile Occasional outbreaks of HAV and higher proportions of symptomatic cases are reported amongst older children and adults from different regions of the country The challenge is to recognize the susceptible pockets and take pre-emptive steps The vaccine will be useful in individuals and populations who remain unexposed to the HAV infection during early childhood 1.Mathur P, Arora NK.Epidemiological transition of hepatitis A in India: issues for vaccination in developing countries.Indian J Med Res. 2008 Dec;128(6):699-704
  • Hepatitis A vaccine cost The current cost of two paediatric doses of HAV vaccine in india is almost 2000 INR (US$ 50), while HAV antibody assay is available for approximately 900 INR (US$ 23) per test
  • WHO response • Raising awareness, promoting partnerships and mobilizing resources • Formulating evidence-based policy and data for action • Preventing transmission • Executing screening, care and treatment
  • Key facts • Hepatitis A is a viral liver disease that can cause mild to severe illness. • Globally, there are an estimated 1.4 million cases of hepatitis A every year. • The hepatitis A virus is transmitted through ingestion of contaminated food and water, or through direct contact with an infectious person. • Hepatitis A is associated with a lack of safe water and poor sanitation. • Epidemics can be explosive in growth and cause significant economic losses. • Improved sanitation and the hepatitis A vaccine are the most effective ways to combat the disease