Globally, acute hepatitis is frequently caused by the hepatitis A virus. Unlike hepatitis B and C, the hepatitis A virus does not induce chronic liver damage. Fulminant hepatitis is a rare complication of acute hepatitis; it often manifests as a self-limiting sickness.
An acute infection’s typical symptoms include nausea, abdominal discomfort, vomiting, low appetite, exhaustion, malaise, and fever; supportive treatment is used to treat these symptoms.
Children older than 12 months of age and adults at risk of exposure, such as those who travel to regions where the virus is endemic, engage in homogenous sexual activity or drug abuse, exposed at work, or have chronic liver illness, should have the hepatitis vaccine.
Epidemiology
The age group contracting hepatitis A has changed due to improved sanitation. There has been a decrease in the frequency of new infections in recent years. Low endemicity is present in the United States. People with anti-HAV antibodies with a history of infection are prevalent in Mexico.
States that are close to Mexico in the United States have a higher incidence of acute hepatitis. The reported incidence of hepatitis A has dropped by 90% to just 1.2 cases per 100,000 people.
Children and states where systematic immunization began in 1999 have experienced the highest declines. The average age of individuals with hepatitis A has increased over the last four decades.
Anatomy
Pathophysiology
Animal studies that found HAV (Hepatitis A virus) antigens in intestinal crypt epithelial cells and lamina propria cells in the small intestine imply that replication may also occur at these locations. When a virus is swallowed orally, the gastrointestinal system absorbs it, and the HAV particles are then transported via the portal circulation to the basolateral membrane of the hepatocyte.
Acute HAV infection causes hepatocellular damage that is mediated by several immunological systems. It has been demonstrated that individuals with acute HAV infection experience cytotoxic interferon-gamma production from virus-specific T cells. Recent mice models have shown that HAV causes inflammation and hepatocellular death linked to the innate immune response.
The diagnostic serologic assays are a result of the humoral immune response. HAV is eradicated in bile and discharged into the feces after replicating in the liver. The person is most contagious during the two weeks before the start of jaundice when the virus concentration in the stool is at its maximum. One week after jaundice first manifests, most individuals are not contagious, and virus is eliminated through stools and viremia is reduced.
Etiology
Infection with HAV is one of the most widespread causes of acute hepatitis around the world. According to the WHO, HAV infects over 1.5 million people every year. Endemic rates are high in developing nations with inadequate socioeconomic situations and poor sanitation and hygiene standards.
In these underdeveloped nations, exposure typically happens during childhood. Infections are low in developed nations like Western Europe, the United States, and Canada. Intravenous drug users, males engaged in homogenous sexual intercourse, tourists visiting endemic areas, and isolated communities like nursing homes and even day-care facilities have been recognized as high-risk groups in low-endemicity countries.
The prevalence of HAV in a specific population is related to socioeconomic factors such as income, sanitation, and water quality. The prevalence of HAV in the United States has fallen after immunization was implemented. Most transmission cases occur from person to person and are limited to close interactions. An infrequent cause of hepatitis A is blood transfusion.
Genetics
Prognostic Factors
The majority of HAV patients have excellent outcomes. Long-term immunity is typical after an infection, and unlike other viral hepatitis infections, the return of symptoms is uncommon. Death is uncommon; however, it can occur in the elderly or those with an underlying liver condition.
Every year, around a hundred people die from HAV in the United States. A liver transplant has only been performed occasionally in children with fulminant illness. Age is the most important prognostic indicator; the more the person’s age, the more probable an adverse reaction or incident will occur. Long-term consequences are pretty unusual.
for the contacts of Household and institutional hepatitis A Â
 Persons traveling to areas where hepatitis A is common: Â
Dosing is divided based on the duration of stay to areas where hepatitis A is common Â
For one month stay: 0.1 mL/kg intramuscularly IM  Â
For two months stay: 0.2 mL/kg intramuscularly IM  Â
More than two months stay: 0.2 mL/kg intramuscularly IM every two months Â
Indicated as a proactive immunization for anyone looking for protection or who may be susceptible to contracting a HAV infection
At-risk populations such as those with chronic liver disease, homosexuals (men), abandoned persons, HIV infection, drug use (injection or oral), research subjects who have hepatitis A virus, traveling to endemic countries with high or medium HAV infection, close association with international individuals from countries of high or medium risk of HAV infection after their arrival within first two months of contact, risk of infection during pregnancy, exposure settings if any Subjects with international adoptee exposure contact need to get the first dose within two weeks before arrival from their country, which has a high or medium risk of HAV infection
Adults who are above 19 years should receive a single 1-mL dosage for their primary immunization, followed by a booster dose given at any time between six and twelve months later The deltoid region is where adults should receive the injection
Travelers who need protection against HAV infection pre-exposure should receive 1 mL IM two weeks before their travel to countries with a risk of HAV infection The primary dose needs to be administered to individuals who are not vaccinated once the travel is scheduled, and a two-dose series needs to be completed according to the regular schedule
For immunocompromised individuals such as those with chronic liver disease or who are above 40 years or older, immune globulin needs to be considered for administration as an adjunctive
Prophylaxis for post-exposure individuals for HAV infection is 1 mL via IM as a primary dose, and if ACIP guidelines follow, a two-dose series needs to be completed Above 40 years, individuals need to get an additional immunoglobulin Immunocompromised individuals need to get a two-dose vaccine series along with immunoglobulin
Dose Adjustments
For immunocompromised individuals such as those with chronic liver disease or who are above 40 years or older, immune globulin needs to be considered for administration as an adjunctive
Age: 12 months-40 yearsÂ
0.1 mL/kg intramuscularly IM for the contacts of Household and institutional hepatitis A Â
Dosing is divided based on the duration of stay to areas where hepatitis A is common. Â
For one month stay: 0.1 mL/kg intramuscularly IM  Â
For two months stay: 0.2 mL/kg intramuscularly IM  Â
More than two months stay: 0.2 mL/kg intramuscularly IM every two months
Recommended as a regular immunization for kids who are at least 12 months old (ACIP guidelines)
Less than 12 months: Not recommended; if given, does not count toward the standard 2-dose series
In children between 12 months and 18 years old, a two-dose series is recommended, with a primary dose of 0.5 mL administered IM and a booster dose given six or 12 months after the first dose (Havrix) The booster dose is given either six or 18 months after the first dose
Those who are not immune to HAV infections must adhere to a catch-up regimen that calls for a 6-to 18-month gap between doses in order to receive vaccinations The recommended dosing interval of six months must be adhered to at minimum
In order to protect themselves against HAV infection prior to travel, travellers should receive immunoglobulin if they are younger than six months old and should not receive a conventional two-dose series For children between six and eleven months, they should receive 0.5 mL of immunoglobulin Children who have not received a prior vaccination and are between the ages of one and eighteen must receive 0.5 mL and finish a two-dose series Immunoglobulin and vaccination administration is recommended for immunocompromised patients
If ACIP recommendations be followed, a two-dose series must be finished as prophylaxis for HAV infection in post-exposure individuals aged 1 to 18 years who have not received a prior vaccination The initial dose is 0.5 mL by intramuscular injection Immunocompromised people require immunoglobulin in addition to a two-dose vaccination schedule
International traveling individuals to endemic countries with high or medium risk for HAV infection who are 6 and 11 months should receive a dose before travel, and after six months, between 1 year and two years, individuals revaccination with the next dose Children above one year need to get the first dose ASAP when travel is scheduled and 2nd dose after six months if not vaccinated previously
Globally, acute hepatitis is frequently caused by the hepatitis A virus. Unlike hepatitis B and C, the hepatitis A virus does not induce chronic liver damage. Fulminant hepatitis is a rare complication of acute hepatitis; it often manifests as a self-limiting sickness.
An acute infection’s typical symptoms include nausea, abdominal discomfort, vomiting, low appetite, exhaustion, malaise, and fever; supportive treatment is used to treat these symptoms.
Children older than 12 months of age and adults at risk of exposure, such as those who travel to regions where the virus is endemic, engage in homogenous sexual activity or drug abuse, exposed at work, or have chronic liver illness, should have the hepatitis vaccine.
The age group contracting hepatitis A has changed due to improved sanitation. There has been a decrease in the frequency of new infections in recent years. Low endemicity is present in the United States. People with anti-HAV antibodies with a history of infection are prevalent in Mexico.
States that are close to Mexico in the United States have a higher incidence of acute hepatitis. The reported incidence of hepatitis A has dropped by 90% to just 1.2 cases per 100,000 people.
Children and states where systematic immunization began in 1999 have experienced the highest declines. The average age of individuals with hepatitis A has increased over the last four decades.
Animal studies that found HAV (Hepatitis A virus) antigens in intestinal crypt epithelial cells and lamina propria cells in the small intestine imply that replication may also occur at these locations. When a virus is swallowed orally, the gastrointestinal system absorbs it, and the HAV particles are then transported via the portal circulation to the basolateral membrane of the hepatocyte.
Acute HAV infection causes hepatocellular damage that is mediated by several immunological systems. It has been demonstrated that individuals with acute HAV infection experience cytotoxic interferon-gamma production from virus-specific T cells. Recent mice models have shown that HAV causes inflammation and hepatocellular death linked to the innate immune response.
The diagnostic serologic assays are a result of the humoral immune response. HAV is eradicated in bile and discharged into the feces after replicating in the liver. The person is most contagious during the two weeks before the start of jaundice when the virus concentration in the stool is at its maximum. One week after jaundice first manifests, most individuals are not contagious, and virus is eliminated through stools and viremia is reduced.
Infection with HAV is one of the most widespread causes of acute hepatitis around the world. According to the WHO, HAV infects over 1.5 million people every year. Endemic rates are high in developing nations with inadequate socioeconomic situations and poor sanitation and hygiene standards.
In these underdeveloped nations, exposure typically happens during childhood. Infections are low in developed nations like Western Europe, the United States, and Canada. Intravenous drug users, males engaged in homogenous sexual intercourse, tourists visiting endemic areas, and isolated communities like nursing homes and even day-care facilities have been recognized as high-risk groups in low-endemicity countries.
The prevalence of HAV in a specific population is related to socioeconomic factors such as income, sanitation, and water quality. The prevalence of HAV in the United States has fallen after immunization was implemented. Most transmission cases occur from person to person and are limited to close interactions. An infrequent cause of hepatitis A is blood transfusion.
The majority of HAV patients have excellent outcomes. Long-term immunity is typical after an infection, and unlike other viral hepatitis infections, the return of symptoms is uncommon. Death is uncommon; however, it can occur in the elderly or those with an underlying liver condition.
Every year, around a hundred people die from HAV in the United States. A liver transplant has only been performed occasionally in children with fulminant illness. Age is the most important prognostic indicator; the more the person’s age, the more probable an adverse reaction or incident will occur. Long-term consequences are pretty unusual.
https://www.ncbi.nlm.nih.gov/books/NBK459290/
medtigo
Hepatitis A
Updated :
February 6, 2024
Globally, acute hepatitis is frequently caused by the hepatitis A virus. Unlike hepatitis B and C, the hepatitis A virus does not induce chronic liver damage. Fulminant hepatitis is a rare complication of acute hepatitis; it often manifests as a self-limiting sickness.
An acute infection’s typical symptoms include nausea, abdominal discomfort, vomiting, low appetite, exhaustion, malaise, and fever; supportive treatment is used to treat these symptoms.
Children older than 12 months of age and adults at risk of exposure, such as those who travel to regions where the virus is endemic, engage in homogenous sexual activity or drug abuse, exposed at work, or have chronic liver illness, should have the hepatitis vaccine.
The age group contracting hepatitis A has changed due to improved sanitation. There has been a decrease in the frequency of new infections in recent years. Low endemicity is present in the United States. People with anti-HAV antibodies with a history of infection are prevalent in Mexico.
States that are close to Mexico in the United States have a higher incidence of acute hepatitis. The reported incidence of hepatitis A has dropped by 90% to just 1.2 cases per 100,000 people.
Children and states where systematic immunization began in 1999 have experienced the highest declines. The average age of individuals with hepatitis A has increased over the last four decades.
Animal studies that found HAV (Hepatitis A virus) antigens in intestinal crypt epithelial cells and lamina propria cells in the small intestine imply that replication may also occur at these locations. When a virus is swallowed orally, the gastrointestinal system absorbs it, and the HAV particles are then transported via the portal circulation to the basolateral membrane of the hepatocyte.
Acute HAV infection causes hepatocellular damage that is mediated by several immunological systems. It has been demonstrated that individuals with acute HAV infection experience cytotoxic interferon-gamma production from virus-specific T cells. Recent mice models have shown that HAV causes inflammation and hepatocellular death linked to the innate immune response.
The diagnostic serologic assays are a result of the humoral immune response. HAV is eradicated in bile and discharged into the feces after replicating in the liver. The person is most contagious during the two weeks before the start of jaundice when the virus concentration in the stool is at its maximum. One week after jaundice first manifests, most individuals are not contagious, and virus is eliminated through stools and viremia is reduced.
Infection with HAV is one of the most widespread causes of acute hepatitis around the world. According to the WHO, HAV infects over 1.5 million people every year. Endemic rates are high in developing nations with inadequate socioeconomic situations and poor sanitation and hygiene standards.
In these underdeveloped nations, exposure typically happens during childhood. Infections are low in developed nations like Western Europe, the United States, and Canada. Intravenous drug users, males engaged in homogenous sexual intercourse, tourists visiting endemic areas, and isolated communities like nursing homes and even day-care facilities have been recognized as high-risk groups in low-endemicity countries.
The prevalence of HAV in a specific population is related to socioeconomic factors such as income, sanitation, and water quality. The prevalence of HAV in the United States has fallen after immunization was implemented. Most transmission cases occur from person to person and are limited to close interactions. An infrequent cause of hepatitis A is blood transfusion.
The majority of HAV patients have excellent outcomes. Long-term immunity is typical after an infection, and unlike other viral hepatitis infections, the return of symptoms is uncommon. Death is uncommon; however, it can occur in the elderly or those with an underlying liver condition.
Every year, around a hundred people die from HAV in the United States. A liver transplant has only been performed occasionally in children with fulminant illness. Age is the most important prognostic indicator; the more the person’s age, the more probable an adverse reaction or incident will occur. Long-term consequences are pretty unusual.
https://www.ncbi.nlm.nih.gov/books/NBK459290/
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