
Georgia
Nov 30, 1919, 12:00 AM
Post #16 of 36
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A question about immunization
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If you are immunized against hepatitis A and you are exposed to it in tainted food, does it provide total protection or just reduce the severity of the disease? What about the typhoid vaccine? Same question.<p>: RexC writes: : "We sometimes do buy food from street vendors. That said, I would advise anyone that thinks they may ever be at risk of contracting Hepatitus to get the immunity shots for that disease.<p>: I am from Alaska. Hepatitus is endemic in the villages up there. My health care provider up there is The Alaska Native Hospital. I am eligible for Indian Health care, and The Native Hospital is a subcontractor for The Indian Health Service.<p>: About 20 years ago, they advised all patients to get the shots. It is one of the few programs that includes the non Indian, or non native, spouses of patients. At that time it took 3 or 4 visits to get the complete series of shots. First you are tested to see if you have ever had Hepatitus, and have developed a natural immunity. <p>: If you don't have immunity, you recieve a series of three shots. You are then tested again, to verify that the shots were efective, and that you are now immune. The immunity lasts for life, and it is effective for both Hepatitus A and B. Today, there may be a simpler method to administer the shots."<p>: You are meandering between two distinctly different diseases, Hepatitis A and Hepatitis B, and ending with an incorrect and potentially dangerous assertion "....and it is effective for both Hepatitus [sic] A and B." There are separate and distinctly different vaccinations for Hepatitis A and Hepatitis B; NEITHER CONFER CROSS-IMMUNITY AGAINST THE OTHER DISEASE. <p>: Hepatitis A, caused by the Hepatitis A Virus (HAV), is transmitted by the fecal/oral route. Common methods of transfer include ingestion of contaminated food or water, or close personal contact with an infected person. Hepatitis A is endemic in many parts of the world including Central and South America, the Caribbean, parts of Asia, Africa, and southern and eastern Europe. In the US Hepatitis A falls into the top 10 most common infectious diseases, along with such goodies as gonorrhea, chicken pox, syphilis, and HIV.<p>: Vaccines for Hepatitis A are a relatively recent development, coming onto the market approximately 10 years ago, and not actually coming into common use until the mid-90's. Prior to this time, persons who were thought to be exposed to Hepatitis A were often treated with gammaglobulin (Hepatitis A Immune Globulin, HAIG), which provided a short-term boost to the immune system. For adults, both of the two Hepatitis A vaccines on the market in the US (SmithKline Beecham's Havrix, and Merck's VAQTA) are administered in two doses, an initial dose, and a second "boosting" dose 6-12 months later (there's a single high-dose application that's been added in the past year or so apparently for use in post-exposure treatments). When the second boosting dose is used, immunity is expected to last for a lifetime. <p>: Blood testing (antibody titers) for Hepatitis A exposure and immunity is relatively uncommon and used mostly for research or during epidemiological investigations of local outbreaks. It would be unusual to perform a titer before immunization for prior Hepatitis A exposure, or post-immunization to verify immunity. <p>: Hepatitis B, caused by the Hepatitis B virus (HBV), is transmitted when the blood or body fluids from an infected person enters into the body of somebody who is not immune. Common means of transmission are unprotected sex and sharing of needles and equipment used for injecting drugs; needlesticks and other sharps contacts pose exposure hazards for a number of groups of workers including those in healthcare. Hepatitis B is NOT transmitted by fecal matter or sewage, and you cannot develop Hepatitis B from eating contaminated food or drinking contaminated water.<p>: Hepatitis B vaccines first came onto the market in the early 1980s. The current recombinant DNA-based vaccines (in the US GlaxoSmithKline's Engerix-B, and Merck's Recombivax HB) were introduced in the late 1980s. These vaccines are administered in three doses, an initial, one a month later, and one approximately six months following the initial (recently one of the manufacturers has had a two-dose regimen approved for adolescents). Although it's been found that serum levels of the HBV antibody decline over time, immunity from the full three vaccine series is expected to last a lifetime. Originally serological (blood) testing was conducted before vaccination to detect "latent" HBV infections, and 2-3 months following the third vaccine to verify immunity. In recent years, however, the use of blood titers has fallen off because of the increase in the percentage of the population which has been immunized, and confidence in the effectiveness of the vaccine (post-immunization titers are still generally recommended for health care professionals and others at high risk of HBV exposure).<p>: It should be noted that in addition to Hepatitis A and Hepatitis B, there's also Hepatitis C, D, and E/G. Currently there are no vaccines on the market to prevent infections from these somewhat rarer forms of Hepatitis.<p>
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