Twinrix
Encyclopedia
Twinrix is a vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

 against hepatitis A
Hepatitis A
Hepatitis A is an acute infectious disease of the liver caused by the hepatitis A virus , an RNA virus, usually spread the fecal-oral route; transmitted person-to-person by ingestion of contaminated food or water or through direct contact with an infectious person...

 and hepatitis B, manufactured by GlaxoSmithKline
GlaxoSmithKline
GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...

. Twinrix is administered over three doses.

The name was created because it is a mixture of two earlier vaccines - Havrix, an inactivated-virus Hepatitis A vaccine
Hepatitis A vaccine
Hepatitis A vaccine is a vaccine against the hepatitis A virus. The first successful vaccine against it was invented by Maurice Hilleman at Merck. The vaccine protects against the virus in more than 95% of cases and provides protection from the virus for at least ten years...

, and ENGERIX-B, a recombinant Hepatitis B vaccine
Hepatitis B vaccine
Hepatitis B vaccine is a vaccine developed for the prevention of hepatitis B virus infection. The vaccine contains one of the viral envelope proteins, hepatitis B surface antigen . It is produced by yeast cells, into which the genetic code for HBsAg has been inserted...

.

Twinrix first entered the market in early 1997.

Administration schedule

Twinrix can be administered on the same schedule as monovalent Hepatitis B vaccine: at 0- 1- and 6- months. In some circumstances, an accelerated dosing schedule of 0- 7- and 21-to 30- days followed by a booster at 12 months can be used and is believed to have similar efficacy as the traditional schedule.

Efficacy

The CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 reports that clinical trials found the following levels of protection against Hep A and Hep B one month after each dose:
A: 93.8%, 98.8%, 99.9%
B: 30.8%, 78.2%, 98.5%

GlaxoSmithKline claims that its studies found 70% of subjects had antibodies against hepatitis B a month after just the first dose, however.

Autoimmune concerns

Although Twinrix has enjoyed much success and has provided benefit for millions, there is one report concerning a putative exacerbation of autoimmune hepatitis
Autoimmune hepatitis
Autoimmune Hepatitis is a disease of the liver that occurs when the body's immune system attacks cells of the liver. Anomalous presentation of human leukocyte antigen class II on the surface of hepatocytes, possibly due to genetic predisposition or acute liver infection, causes a cell-mediated...

 possibly due to innoculation by Twinrix.. It must be noted, however, that since the vaccination for Hepatitis A is a killed vaccine, and Hepatitis B is a recombinant vaccine, that there is no possibility for the vaccination to mutate and cause Hepatitis A or B in an immunized individual.

Advertising

In order to promote this new vaccine, GlaxoSmithKline
GlaxoSmithKline
GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...

 launched a TV ad advertising, dramatizing that in Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 destinations like the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...

, a person can get Hepatitis A and/or Hepatitis B from an otherwise calm beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...

 setting, from the sand soil
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

 up to the swimming water.

TWINRIX, HAVRIX and ENGERIX-B are registered trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

s of GlaxoSmithKline; if the same vaccine is available from others, it will have another name.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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