Hepatitis A vaccine is a

vaccine A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified.

that prevents

hepatitis A Hepatitis A is an infectious disease of the liver caused by ''Hepatovirus A'' (HAV); it is a type of viral hepatitis. Many cases have few or no symptoms, especially in the young. The time between infection and symptoms, in those who develop them ...

.Lay summary
It is effective in around 95% of cases and lasts for at least twenty years and possibly a person's entire life. If given, two doses are recommended beginning after the age of one. It is given by

injection into a muscle Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles ha ...

. The first hepatitis A vaccine was approved in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

in 1991, and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

in 1995. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...

. The

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...

(WHO) recommends universal vaccination in areas where the disease is moderately common. Where the disease is very common, widespread vaccination is not recommended as all people typically develop immunity through infection during childhood. The

Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...

(CDC) recommends vaccinating: * All children aged 12–23 months * Unvaccinated children and adolescents aged 2–18 years * International travelers *

Men who have sex with men Men who have sex with men (MSM) are male persons who engage in sexual activity with members of the same sex. The term was created in the 1990s by epidemiologists to study the spread of disease among all men who have sex with men, regardless of ...

* People who use injection or non-injection drugs * People who have occupational risk for infection * People who anticipate close contact with an international adoptee * People experiencing homelessness * People with

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

* People with

chronic liver disease Chronic liver disease in the clinical context is a disease process of the liver that involves a process of progressive destruction and regeneration of the liver parenchyma leading to fibrosis and cirrhosis. "Chronic liver disease" refers to disease ...

* Any person wishing to obtain immunity In addition, a person who has not previously received hepatitis A vaccine and who has direct contact with someone with hepatitis A should get hepatitis A vaccine within two weeks after exposure. Severe side effects are very rare. Pain at the site of injection occurs in about 15% of children and half of adults. Most hepatitis A vaccines contain inactivated virus while a few contain weakened virus. The ones with weakened virus are not recommended during

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

or in those with

poor immune function Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reacti ...

. A few formulations combine hepatitis A with either

hepatitis B Hepatitis B is an infectious disease caused by the '' Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. ...

typhoid vaccine Typhoid vaccines are vaccines that prevent typhoid fever. Several types are widely available: typhoid conjugate vaccine (TCV), Ty21a (a live oral vaccine) and Vi capsular polysaccharide vaccine (ViPS) (an injectable subunit vaccine). They are ab ...

. Soreness or redness where the shot is given, fever, headache, tiredness, or loss of appetite can happen after hepatitis A vaccine. As with any medicine, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death.

Medical uses

Within the U.S., the vaccine "Vaqta" developed by

Maurice Hilleman Maurice Ralph Hilleman (August 30, 1919 – April 11, 2005) was a leading American microbiologist who specialized in vaccinology and developed over 40 vaccines, an unparalleled record of productivity. According to one estimate, his vaccines ...

and his team at Merck & Co. was licensed in 1995. The vaccine was phased in, around 1996, for children living in high-risk areas. In 1999, its usage was spread to areas with elevating levels of infection. In the U.S. , the vaccine is strongly recommended for all children 12 to 23 months of age in an attempt to eradicate the virus nationwide. Although the original

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) license for Havrix by GlaxoSmithKline is dated in 1995, it had been approved in Europe in 1991. The U.S.

(CDC), recommends vaccination of all children over one year of age, people whose sexual activity puts them at risk, people with chronic liver disease, people who are being treated with clotting factor concentrates, people working in close proximity to the virus, and people who are living in communities where an outbreak is present. Hepatitis A is the most common vaccine-preventable virus acquired during travel, so people traveling to places where the virus is common like the Indian subcontinent, Africa, Central America, South America, Asia, and Eastern Europe should be vaccinated. The vaccine is given in the muscle of the upper arm, in two doses for the best protection. The initial dose of the vaccine should be followed up by a booster six to twelve months later. Protection against hepatitis A begins approximately two to four weeks after the initial vaccination. Protection lasts at least 15 years and is estimated to last at least 25 years if the booster is administered. A

Cochrane review Cochrane (previously known as the Cochrane Collaboration) is a British international charitable organisation formed to organise medical research findings to facilitate evidence-based choices about health interventions involving health profes ...

found that both types of vaccines offer significant protection, for at least two years using the inactivated vaccine and at least five years with the attenuated vaccine. The review concluded that the inactivated vaccine is safe, but required more high quality evidence to assess the safety of the attenuated vaccine.

Commercial vaccines

Several commercial hepatitis A vaccines are available. The definition of (U)nits varies among manufacturers depending on how hepatitis A antigen is measured in their products. * Avaxim: made by

Sanofi Pasteur Sanofi Pasteur is the vaccines division of the French multinational pharmaceutical company Sanofi. Sanofi Pasteur is the largest company in the world devoted entirely to vaccines. It is one of four global producers of the yellow fever vaccine. ...

. Inactivated hepatitis A virus produced in

MRC-5 MRC-5 ( Medical Research Council cell strain 5) is a diploid cell culture line composed of fibroblasts, originally developed from the lung tissue of a 14-week-old aborted Caucasian male fetus. The cell line was isolated by J.P. Jacobs and colle ...

cells. Each dose contains 160U of antigen adsorbed on

aluminium hydroxide Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic an ...

(0.3 mg Al). * Epaxal: made by

Crucell Janssen Vaccines, formerly Crucell, is a biotechnology company specializing in vaccines and biopharmaceutical technologies. It was formed when Johnson & Johnson acquired the Dutch biotech company Crucell based in Leiden and placed it in their ph ...

. Also sold under the brand names HAVpur and VIROHEP-A. This vaccine consists of

virosome A virosome is a drug or vaccine delivery mechanism consisting of unilamellar phospholipid membrane (either a mono- or bi-layer) vesicle incorporating virus derived proteins to allow the virosomes to fuse with target cells. Viruses are infectious ...

s, artificial particles composed of synthetic

lipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

and influenza proteins in addition to the hepatitis A antigen. It does not contain

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

. * Havrix: made by GlaxoSmithKline. Inactivated hepatitis A virus produced in MRC-5 cells. Each adult dose contains 1440

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presen ...

units of viral antigen adsorbed on aluminium hydroxide (0.5 mg Al). The pediatric (child) doses contain half the amount of viral antigen and aluminium. * Healive: made by

Sinovac Sinovac Biotech Ltd. () is a Chinese biopharmaceutical company based in Haidian District, Beijing that focuses on the research, development, manufacture, and commercialization of vaccines that protect against human infectious diseases. The comp ...

. Inactivated hepatitis A virus cultured in human

diploid cell Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

, followed by harvest, purification, inactivation, and aluminium adsorption. Each adult dose contains 500U of viral antigen. The pediatric dose contains 250U of viral antigen. * Vaqta: made by

Merck Merck refers primarily to the German Merck family and three companies founded by the family, including: * the Merck Group, a German chemical, pharmaceutical and life sciences company founded in 1668 ** Merck Serono (known as EMD Serono in the Unite ...

. Inactivated hepatitis A virus produced in MRC-5 cells. An adult dose contains 50U of antigen adsorbed onto 0.45 mg of aluminium (as aluminium hydroxyphosphate sulfate); a child dose contains half the amounts of antigen and aluminium. * Biovac-A: made by Pukang, sold under the brand name Biovac-A in India and under the brand names Mevac-A in Guatemala, Philippines, Bangladesh, Nepal, Uzbekistan and Chile etc. It is a

freeze-dried Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product and lowering pressure, removing the ice by sublimation. This is in contrast to dehydration by most conve ...

live attenuated hepatitis A vaccine. Hepatitis A virus H2 strain is produced in human diploid cells. A pack of 0.5ml vial of Biovac-A and 0.5ml ampoule of SWFI (sterile water for injection), contains not be less than 6.5 Lg CCID50. Only a single dose is needed. It is recommended by the WHO. Long term persistence research data predicated that sero-conversion remained and antibody titre was not less than 128IU/ml, 15 years after vaccination.

Combination vaccines

* Hepatitis A and B vaccine is a vaccine against hepatitis A and

. * Hepatitis A and typhoid vaccine is a vaccine against hepatitis A and

typhoid Typhoid fever, also known as typhoid, is a disease caused by ''Salmonella'' serotype Typhi bacteria. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several d ...

References

External links

* {{DEFAULTSORT:Hepatitis A Vaccine Hepatitis A GSK plc brands Hepatitis vaccines Inactivated vaccines Merck & Co. brands Wikipedia medicine articles ready to translate World Health Organization essential medicines (vaccines)

Medical uses

Commercial vaccines

Combination vaccines

References

Further reading

External links