Tuesday, May 28, 2024

How Hepatitis B Vaccine Works

Persons New To Canada

HBV Vaccine – Creative Biolabs

Health care providers who see persons newly arrived in Canada should review the immunization status and update immunization for these individuals, as necessary. In many countries outside of Canada, HB vaccine is in limited use.

All persons from a country that is endemic for HB should be assessed and vaccinated against HB if not immune and not infected. Individuals born in developing countries are more likely to be carriers of HB, necessitating vaccination of their sexual and household contacts based on review of their serologic test results. HB vaccine is recommended for all household contacts whose families have immigrated to Canada from areas in which there is a high prevalence of HB and who may be exposed to HB carriers through their extended families or when visiting their country of origin.

Children adopted from countries in which there is a high prevalence of HB infection should be screened for HBsAg and, if positive, household or close contacts in the adopting family should be immunized before adoption or as soon as possible thereafter. Adults going to pick-up children from these countries should be vaccinated before departure. Refer to Immunization of Persons New to Canada in Part 3 for additional information.

What Are The Side Effects

The most common of the hepatitis B vaccine are mild and include:

  • Low fever or,
  • Sore arm from the shot.

Prepare for your child’s vaccine visit and learn about how you can:

  • Research vaccines and ready your child before the visit
  • Comfort your child during the appointment
  • Care for your child after the shot

Why Is The Hepb Vaccine Recommended

People who dont know they’re infected can spread the hepatitis B virus. So it cant be avoided just by being careful. That’s why health experts recommend that all babies get the vaccine right from birth.

The HepB injection usually creates long-term immunity. Most infants who get the HepB series are protected from hepatitis B infection beyond childhood, into their adult years.

Eliminating the risk of infection also decreases risk for cirrhosis of the liver, chronic liver disease, and liver cancer.

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The Impact Of Worldwide Hepatitis B Vaccination Programs: Model Of Success

A, Immunization coverage with third dose of hepatitis B in infants in 2019. B, Global immunization 19892019 HepB3 coverage in infants. Global coverage was 84% in 2019. Abbreviations: AFR,African region AMR,Americas region EMR,Eastern Mediterranean region EUR,European region SEAR,South-East Asia region WPR,Western Pacific region. Source: United Nations Children’s Fund /World Health Organization.

The success of HBV vaccination programs has been clearly demonstrated over the recent years in several regions around the world. Countries that have adopted the recommendation had a marked reduction in carrier rates as well as complications from HBV, including HCC. The low prevalence of chronic HBV infection in children younger than 5 years, reducing from 4.7% in the prevaccine era to less than 1% in 2019, can be attributed to the widespread use of hepatitis B vaccine. Due to the implementation of routinely birth-dose vaccination the greatest decrease appears to be in the Western Pacific region, from 8.3% HBsAg prevalence in the prevaccine era to 0.93% in 20022015 . Among health care workers, hepatitis B vaccination is highly effective for the prevention of healthcare associated HBV infection and chronic infection. Using mathematical models, it was estimated that since their implementation, HBV vaccination programs have averted 210 million new HBV infections globally .

Hbig In Liver Transplantation

Hepatitis B in Kiribati: an island epidemic

HBIG is indicated to prevent reinfection in individuals who are undergoing liver transplantation due to hepatitis. If the HBIG is developed with indication for prevention of hepatitis B recurrence following liver transplantation then the clinical development to evaluate efficacy should be done in patients who have undergone liver transplant for liver failure caused by hepatitis B. In the same setting, additional data like antigen-driven complement fixation, opsonisation, phagocytosis, antibody-dependent cell mediated cytotoxicity may also be submitted. The new immunoglobulin for the above-said indication should be studied with at least 25 participants and also with the intended mode and route for administration. The European Medicines Agency accepts open-label uncontrolled studies for clinical development and also recommends to use end-points measuring the proportion of patients who develop a recurrence of hepatitis B as demonstrated by positive results for HBsAg and/or HBeAg, titer of anti-HBs, titer of circulating hepatitis B virus DNA, time to recurrence of hepatitis B, and overall survival.

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If I Already Have Hepatitis B Can The Vaccine Treat It

No. The hepatitis vaccine prevents hepatitis, but doesnt cure it if you already have it. If you have hepatitis B, there are other treatment options.

However, if you recently got exposed to the hepatitis B virus and you havent had the vaccine yet, tell your doctor right away. The vaccine and possibly other treatment can reduce your chances of getting hepatitis B if you get it within 2 weeks after you came into contact with the virus. The sooner you seek care after being exposed to hepatitis B, the better, so try to get there right away.

Babies And Hepatitis B Vaccination

Pregnant women have a routine blood test for hepatitis B as part of their antenatal care.

Babies born to mothers infected with hepatitis B need to be given a dose of the hepatitis B vaccine within 24 hours of their birth, followed by further doses at 4, 8, 12 and 16 weeks of age, plus a final dose when they’re 1 year old.

Babies of mothers identified by the blood test as particularly infectious might also be given an injection of HBIG at birth on top of the hepatitis B vaccination to give them rapid protection against infection.

All babies born to mothers infected with hepatitis B should be tested at 1 year of age to check if they have become infected with the virus.

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British Columbia Specific Information

Hepatitis B is a virus that attacks the liver. It can cause serious disease, including permanent liver damage , and is also the main cause of liver cancer.

The hepatitis B vaccine provides immunity for at least 10 years and likely for a lifetime when completing the full series. There are currently no recommendations for a healthy person to receive a booster for this vaccine if they have completed the full series.

For more information on hepatitis B and the hepatitis B vaccine, see:

You may also call 8-1-1 to speak to a registered nurse or pharmacist. Our nurses are available 24 hours a day, 7 days a week and our pharmacists are available every night from 5:00 p.m. to 9:00 a.m.

Raising Awareness About Hepatitis B And Its Vaccine

Hepatitis B Vaccine

We are seeking funds to build a public engagement platform to foster a better understanding of hepatitis B and the science behind its vaccine. Our platform will be centred around an online digital exhibition that will use historical sources, film footage and 3D animations to tell the story behind the hepatitis B vaccine. This is a compelling story because the HBV vaccine not only dramatically reduced the global burden of hepatitis B, it was also the first vaccine to provide prevention against a human cancer. In addition its development transformed the safety and efficacy of vaccines overall.

Engagement with key stakeholder groups including patients, families, practitioners, scientists, advocacy groups and charities lies at the heart of our project. We will invite these different groups to share their experiences and get involved in guiding the development of the digital exhibition and to participate in conversations around its content when it goes live online. The exhibition will be hosted free online permanently on WhatIsBiotechnology.org.

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How Hepatitis Is Spread

Hepatitis A: About 20,000 people in the U.S. contract hepatitis A each year. The hepatitis A virus is found in the stool of the infected person. It is spread through contaminated food or water or by certain types of sexual contact.

Children who get hepatitis A often don’t have symptoms, so they can have the virus and not know it. However, they can still spread it easily. Fortunately, children are now routinely vaccinated against hepatitis A.

Most people who get hepatitis A recover completely within two weeks to six months and don’t have any liver damage. In rare cases, hepatitis A can cause liver failure and even death in older adults or people with underlying liver disease.

Hepatitis B: Every year, about 40,000 people in the U.S. become infected with hepatitis B. Acute hepatitis lasts from a few weeks to several months. Many infected people are able to clear the virus and remain virus-free after the acute stage. However, for others, the virus remains in the body, and they develop chronic hepatitis B infection, which is a serious, lifelong condition. About 1.2 million people in the U.S. have chronic hepatitis B. Of these, 15% to 25% will develop more serious health problems, such as liver damage, cirrhosis, liver failure, and liver cancer, and some people die as a result of hepatitis B-related disease.

Hepatitis B cannot be spread by contaminated water, food, cooking, or eating utensils, or by breastfeeding, coughing, sneezing, or close contact such as kissing and hugging.

Approaches By Virus Life Cycle Stage

consist of a and sometimes a few stored in a capsule made of , and sometimes covered with a layer . Viruses cannot reproduce on their own and instead propagate by subjugating a host cell to produce copies of themselves, thus producing the next generation.

Researchers working on such “” strategies for developing antivirals have tried to attack viruses at every stage of their life cycles. Some species of mushrooms have been found to contain multiple antiviral chemicals with similar synergistic effects.Compounds isolated from fruiting bodies and filtrates of various mushrooms have broad-spectrum antiviral activities, but successful production and availability of such compounds as frontline antiviral is a long way away. Viral life cycles vary in their precise details depending on the type of virus, but they all share a general pattern:

  • Attachment to a host cell.
  • Release of viral genes and possibly enzymes into the host cell.
  • Replication of viral components using host-cell machinery.
  • Assembly of viral components into complete viral particles.
  • Release of viral particles to infect new host cells.
  • Before cell entry

    This stage of viral replication can be inhibited in two ways:

  • Using agents which mimic the virus-associated protein and bind to the cellular receptors. This may include VAP , natural of the receptor and anti-receptor antibodies.
  • Uncoating inhibitor

    Inhibitors of uncoating have also been investigated.

    During Viral Synthesis

    Reverse transcription

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    Immunogenicity In Healthy Adults And Adolescents:

    Clinical trials in healthy adult and adolescent subjects have shown that following a course of 3 doses of 20 mcg ENGERIX-B given according to the ACIP-recommended schedule of injections at months 0, 1, and 6, the seroprotection rate for all individuals was 79% at month 6 and 96% at month 7 the GMT for seroconverters at month 7 was 2,204 mIU/mL. On an alternate schedule designed for certain populations , 99% of all individuals were seroprotected at month 3 and remained protected through month 12. On the alternate schedule, an additional dose at 12 months produced a GMT for seroconverters at month 13 of 9,163 mIU/mL.

    Who Should Get A Hepatitis B Vaccine


    Vaccination against hepatitis B is recommended for everyone. But, some groups are at an increased risk. These include the following individuals:

    • Men who have sex with men
    • Inject drugs or share needles
    • Live with a person with chronic hepatitis B
    • Hemodialysis patients
    • Travellers to regions with hepatitis B transmission.

    Those who are allergic to products within the vaccine and some individuals with certain health conditions. Consult with a travel health specialist to learn if the vaccine is right for you and your situation.

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    Implementing Strategies For Hepatitis B Vaccination

    When hepatitis B vaccines became available, strategies for HBV control were initially focused on vaccination of high-risk groups . However, high-risk individuals are mostly difficult to reach and are often infected before vaccination . Consequently, coverage of 3 doses of hepatitis B vaccine remained low in most high-risk groups due to low compliance and logistic reasons . In addition, as many as 30% or more people with acute hepatitis B infection do not have identifiable risk factors and are therefore missed by only a high-risk group approach .

    Hence it was clear that an additional global strategy was required as the high-risk strategy made little impact and the global burden of hepatitis B diseases became more and more obvious. Decision makers and health professionals worldwide started to discuss a strategy of universal hepatitis B immunization for a certain age cohort, even in low-endemicity countries. In 1991, the WHOs Global Advisory Group of the Expanded Programme on Immunization recommended that hepatitis B vaccine be integrated into national immunization programs in all countries by 1997 . This 1991 recommendation was endorsed by the World Health Assembly in 1992 . Progressively, it has become more widely used and recommendations for HBV vaccination have been extended in an attempt to achieve maximum protection .

    Reduced Risk Of Hepatocellular Carcinoma:

    According to the CDC, the hepatitis B vaccine is recognized as the first anti-cancer vaccine because it can prevent primary liver cancer.3

    A clear link has been demonstrated between chronic hepatitis B infection and the occurrence of hepatocellular carcinoma. In a Taiwanese study, the institution of universal childhood immunization against hepatitis B virus has been shown to decrease the incidence of hepatocellular carcinoma among children.4 In a Korean study in adult males, vaccination against hepatitis B virus has been shown to decrease the incidence of, and risk of, developing hepatocellular carcinoma in adults.5

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    Immunogenicity In Pediatric Patients:

    In clinical trials with 242 children aged 6 months to, and including, 10 years given 10 mcg at months 0, 1, and 6, the seroprotection rate was 98% 1 to 2 months after the third dose the GMT of seroconverters was 4,023 mIU/mL.

    In a separate clinical trial including both children and adolescents aged 5 to 16 years, 10 mcg of ENGERIX-B was administered at 0, 1, and 6 months or 0, 12, and 24 months . Immediately before the third dose of vaccine, seroprotection was achieved in 92.3% of subjects vaccinated on the 0-, 1-, and 6-month schedule and 88.8% of subjects on the 0-, 12-, and 24-month schedule . One month following the third dose, seroprotection was achieved in 99.5% of children vaccinated on the 0-, 1-, and 6-month schedule compared to 98.1% of those on the 0-, 12-, and 24-month schedule. GMTs were higher for children receiving vaccine on the 0-, 1-, and 6-month schedule compared to those on the 0-, 12-, and 24-month schedule . The clinical relevance of this finding is unknown.

    Who Should Be Immunised Against Hepatitis B

    Hepatitis B vaccine for grade 7 students

    Hepatitis B immunisation is recommended and funded for the following groups:

    • all children up to their 18th birthday
    • babies born to mothers with hepatitis B infection
    • people who live in close contact with someone infected with hepatitis B
    • anyone undergoing renal dialysis
    • people who have hepatitis C infection, or who are HIV positive, or who have had a needle stick injury.
    • anyone who has received immunosuppression therapy of at least 28 days or has had solid organ or bone marrow transplant.

    Hepatitis B immunisation is also recommended, but not funded, for:

    • workers who are likely to come into contact with blood products, or who are at increased risk of needlestick injuries, assault, etc.
    • people who change sex partners frequently such as sex workers
    • people who regularly receive blood transfusions such as people with haemophilia
    • prison inmates
    • current or recent injecting drug users
    • migrants and travellers from or to areas with intermediate or high rates of hepatitis B such as the Asia and Pacific region.

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    Who Strategy For Hepatitis B Immunization

    Although major progress has been achieved in hepatitis B immunization, a number of challenges remain. That is why the WHO called for comprehensive prevention and control of HBV infection and the development of time-specific immunization goals in its member states. The strategy includes the following: universal vaccination of infants within 24 hours of birth, full immunization of infants by routine immunization programs, catch-up vaccination of unimmunized cohorts, and monitoring progress and assessing the impact of immunization .

    Universal Vaccination of Infants Within 24 Hours of Birth: a Real Challenge

    Full Immunization of Infants by Routine Immunization Programs and Catch-Up Vaccination of Unimmunized Cohorts

    Wider provision of the existing, safe and effective HBV vaccine, through universal childhood vaccination and by catch-up vaccination of unimmunized cohorts, will further reduce new hepatitis B infections, reducing rates of chronic illness and death. However, to achieve and/or sustain high coverage, stronger and resilient immunization delivery systems will be needed. Still, some countries adopt risk-grouptargeted vaccination only, instead of adding a universal vaccination program. However, changing demography, increasing immigration, and the current vaccine costs make the cost-benefit ratios in these remaining low-endemicity countries strongly in favor of universal HBV vaccination.

    Monitoring Progress and Assessing the Impact of Immunization

    Origin Of Antiviral Resistance

    The genetic makeup of viruses is constantly changing, which can cause a virus to become resistant to currently available treatments. Viruses can become resistant through spontaneous or intermittent mechanisms throughout the course of an antiviral treatment. Immunocompromised patients, more often than immunocompetent patients, hospitalized with are at the highest risk of developing oseltamivir resistance during treatment. Subsequent to exposure to someone else with the flu, those who received oseltamivir for “post-exposure prophylaxis” are also at higher risk of resistance.

    Multiple strains of one virus can be present in the body at one time, and some of these strains may contain mutations that cause antiviral resistance. This effect, called the , results in immense variation in any given sample of virus, and gives the opportunity for natural selection to favor viral strains with the highest fitness every time the virus is spread to a new host. Also, recombination, the joining of two different viral variants, and , the swapping of viral gene segments among viruses in the same cell, play a role in resistance, especially in influenza.

    Antiviral resistance has been reported in antivirals for herpes, HIV, hepatitis B and C, and influenza, but antiviral resistance is a possibility for all viruses. Mechanisms of antiviral resistance vary between virus types.

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