Introduction To A Hepatitis B Vaccine Biology Essay

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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 (HBsAG). It is produced by yeast cells, into which the genetic code for HBsAg has been inserted. A course of three vaccine injections are given with the second injection at least one month after the first dose and the third injection given six months after the first dose. Afterward an immune system  antibody to HBsAg is established in the bloodstream. The antibody is known as  anti-HBsAg. This antibody and immune system memory then provides immunity to hepatitis B infection. The first vaccine became available in 1981.

Babies born to mothers with active hepatitis B infections are recommended to receive treatment reducing the risk of mother-to-child transmission of the hepatitis B infection. As soon as possible and within 48 hours of birth, newborns are vaccinated with hepatitis B surface antigen (HBsAg) and injected with hepatitis B immunoglobulin (HBIG)

Following the primary course of 3 vaccination , a blood test may be taken after an interval of 1-4 months to establish if there has been an adequate response , which is defined as an anti-hepatitis B surface antigen antibody level above 100 mIU/ml. such a full response occurs in about 85-90 % of individuals.

An antibody level between 10 and 100 mIU/ml is considered a poor response , and these people should receive a single booster vaccination at this time, but do not need further testing.

People who fail to respond (anti-hbs antibody level below 10 10 mIU/ml) should be tested to exclude current or past Hepatitis infection, and given a repeat course of 3 vaccinations, followed by further testing 1-4 months after the second course. Those who still do not respond to a second course of vaccination may respond to a high dose of vaccine or to intradermal administration. Those who still fail to respond will require hepatitis b immunoglobulin if later exposed to the hepatitis B virus .

It is now believed that the hepatitis B vaccine provides indefinite protection .however , it was previously believed that the vaccination would only provide effective cover of between five and seven years,but subsequently it has been appreciated that long -term immunity derives from immunological memory which outlasts the loss of antibody levels and hence subsequent testing and administration of booster doses is not required in successfully vaccinated immunocompetent individuals.

UK guidelines now suggest that for initial responders who require ongoing protection, such as for healthcare workers, only a single booster is advocated at 5 years.


The most common cause of hepatitis b infection in hemodialytic patients is cross contamination to patients via environmental surfaces , equipments , and supplies.the incidence of hbv infection in centers have dropped markedly as a result of isolation strategy for HBsAG positive patints, the implementation of infection control measures and the introduction of HBV vaccine, Prevention of HBV transmission is augmented by correct implementation of isolation strategies and the universal vaccination of susceptible patients.

To prevent mother-to-child HBV transmission , we have to administer postexposure prophylaxis of hepatitis B vaccine (HepB) and hepatitis B immunoglobulin (HBIG) to infants born to HBV-infected women within 12 hours of delivery, followed by completion of the HepB series.

A study was done to determine the rate of hepatitis b surface antibody decay in hemodialysis and peritoneal dialysis patients, The decay rate of anti-HBs titers in the PD group was faster than that in the HD group. Hepatitis B vaccination could not offer long-term protection in HD or PD patients. Post-vaccination testing every 6-12 months is necessary and revaccination may be protective in dialysis patients.

A study was done to determine the efficacy of Hepatitis B vaccination in human immunodeficiency virus-infected adults receiving hemodialysis. Several studies have shown that the development of protective antibody titers after HBV vaccination is much lower in HD patients.

And our study showed that Hepatitis B vaccination should be offered to all HIV-infected End Stage Renal Disease patients because over half of the patients with HIV and End Stage Renal Disease can develop protective antibodies.

A study was done to determine the immunogenicity and the immune memory for hepatitis A and hepatitis B vaccine, ten years post vaccination, all subjects were anti-HAV seropositive (≥15 mIU/mL), 81.7% had anti-HBs antibody concentrations ≥10 mIU/mL. All subjects with anti-HBs concentrations <10 mIU/mL, mounted a vigorous anamnestic response to an HBV vaccine challenge dose indicating the presence of immunologic memory against hepatitis B.

. Many countries now routinely vaccinate infants against hepatitis B. In countries with high rates of hepatitis B infection, vaccination of newborns has not only reduced the risk of infection, but has also led to marked reduction in liver cancer. This was reported in Taiwan  where the implementation of a nationwide hepatitis B vaccination program in 1984 was associated with a decline in the incidence of childhood hepatocellular carcinoma. In many areas, vaccination against hepatitis B is also required for all health-care and laboratory staff.