Monday, January 23, 2023

History Of Hepatitis B Vaccine

Persons With Inadequate Immunization Records

The History Of Vaccines And Why Sales Are Rising

Evidence of long term protection against HB has only been demonstrated in individuals who have been vaccinated according to a recommended immunization schedule. Independent of their anti-HBs titres, children and adults lacking adequate documentation of immunization should be considered susceptible and started on an immunization schedule appropriate for their age and risk factors. Refer to Immunization of Persons with Inadequate Immunization Records in Part 3 for additional information.

Why A Variety Of Hepatitis B Vaccine Schedules Have Been Used

Generally, the recommended number of doses of hepatitis B vaccine required to induce protective immunity varies by product and with the age of the recipient. Historically, the standard 3-dose hepatitis B vaccine series has consisted of 2 priming doses administered 1 month apart and a third dose administered 6 months after the first dose. Today, the WHO recommends multiple options for adding hepatitis B vaccine to existing infant immunization schedules. Several options are considered to be appropriate for infants: 1 birth dose followed by either 2 doses of monovalent or hepatitis B containing combination vaccine at 1 and 6 months of age or at 2, 4, and 6 months of age or at 3, 5, and 11 months of age or at 8, 12, 16 weeks and 12 or 15 months or at 6, 10, and 14 weeks of age, according to the WHOs Expanded Programme on Immunization schedule . Currently, a variety of hepatitis B vaccine schedules have been used successfully worldwide. In general, preference is given to effective options that require minimal additional visits for immunization, to increase compliance and to reduce the logistics burden.

Acute Hepatitis B Infection

An acute hepatitis B infection may last up to six months and infected persons are able to pass the virus to others during this time. A simple blood test can let a person know if the hepatitis B virus is in their blood or if they have successfully gotten rid of the virus. The doctor should periodically test your blood over the six-month period to monitor the health of your liver and check progress towards recovery. In a person who has recovered from an acute hepatitis B infection, a taken six-months after initial diagnosis will show that there is no more hepatitis B virus in your blood.

Being diagnosed with acute hepatitis B can be difficult. As you move through the initial six-month period, there are tips and strategies to help.

Until your health care provider confirms that the blood test shows that there is no more hepatitis B virus in your blood, it is important to protect others from a possible infection.

It is also important to have your sexual partner and family members get tested for hepatitis B. If they have not been infected and have not received the hepatitis B vaccine then they should also start the hepatitis B vaccine series.

Be sure to follow-up with your health care provider for any additional blood tests that are needed to confirm your recovery from an acute infection.

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Detection Of Antiviral Resistance

National and international surveillance is performed by the CDC to determine effectiveness of the current FDA-approved antiviral flu drugs. Public health officials use this information to make current recommendations about the use of flu antiviral medications. further recommends in-depth epidemiological investigations to control potential transmission of the resistant virus and prevent future progression. As novel treatments and detection techniques to antiviral resistance are enhanced so can the establishment of strategies to combat the inevitable emergence of antiviral resistance.

Discovery Of The Dane Particle

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AuAg, however, was not a prion-like agent. While inspecting AuAg immune complexes under the EM in 1970, David S. Dane discovered that AuAg appeared not only on the small pleomorphic particles, but also on larger, virus-like objects 42nm in size with a clearly visible inner core . Shortly thereafter, in 1971, his British colleague June Almeida was able to release the core particles from the so-called Dane particles by treatment with mild detergent, and showed by immune EM that hepatitis B patients formed antibodies against this core antigen . This strongly suggested that the Dane particles were the actual virus causing hepatitis B. AuAg was obviously the surface antigen of the virus envelope, and was named HBsAg thereafter. The infected hepatocyte forms the HBsAg protein in large surplus and secretes it in addition to the complete virus as round or filamentous noninfectious particles of about 20nm in diameter into the blood leading to an approximately three-thousand fold excess of these subviral particles .2). This was the reason that the Dane particles could not be recognized in AuAg preparations purified by ultracentrifugation or size chromatography.

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How Is The Hepatitis B Vaccine Made

People are protected against hepatitis B virus infection by making an immune response to a protein that sits on the surface of the virus. When hepatitis B virus grows in the liver, an excess amount of this surface protein is made. The hepatitis B vaccine is made by taking the part of the virus that makes surface protein and putting it into yeast cells. The yeast cells then produce many copies of the protein that are subsequently used to make the vaccine. When the surface protein is given to children in the vaccine, their immune systems make an immune response that provides protection against infection with the hepatitis B virus.

The first hepatitis B vaccine was made in the 1980s by taking blood from people infected with hepatitis B virus and separating or purifying the surface protein from the infectious virus. Because blood was used, there was a risk of contaminating the vaccine with other viruses that might be found in blood, such as HIV. Although contamination with HIV was a theoretical risk of the early, blood-derived hepatitis B vaccine, no one ever got HIV from the hepatitis B vaccine. That is because the blood used to make vaccine was submitted to a series of chemical treatments that inactivated any possible contaminating viruses. Today, there is no risk of contaminating the vaccine with other viruses because the surface protein is manufactured in the laboratory.

How Is Hepatitis B Diagnosed

Because clinical manifestations of hepatitis B are indistinguishable from other causes of viral hepatitis, a definitive diagnosis requires serological testing . This testing uses different serologic markers to identify different phases of HBV infection and to conclude whether a person has acute or chronic HBV infection, or is immune to HBV as a result of prior HBV infection or vaccination, or is susceptible to infection . In Table 1 an interpretation of hepatitis B serologic test results is given.

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Why Should I Vaccinate My Newborn Child If I Know That I Am Not Infected With Hepatitis B Virus

Before the hepatitis B vaccine, every year in the United States about 18,000 children were infected with hepatitis B virus by the time they were 10 years old. This statistic is especially important because people are much more likely to develop liver cancer or cirrhosis if they are infected early in life, rather than later in life .

About 9,000 of the 18,000 children infected in the first 10 years of life caught the virus from their mother during birth. However, many young children didn’t catch the disease from their mother. They caught it from either another family member or someone else who came in contact with the child. Because hepatitis B can be transmitted by relatively casual contact with items contaminated with the blood of an infected person, and because many people who are infected with hepatitis B virus don’t know that they have it, it is virtually impossible to be “careful enough” to avoid this infection.

For these reasons, all young children are recommended to receive the hepatitis B vaccine. The best time to receive the first dose is right after birth. This will ensure that the child will be protected as early as possible from catching hepatitis B from people who dont know that they are infected with the virus.

Listen to Dr. Offit explain why newborns get the hepatitis B vaccine by watching this short video, part of the series Talking About Vaccines with Dr. Paul Offit.

Pathogenesis Of Chronic Hepatitis B

Hepatitis B: Update 2021 Webinar

During acute hepatitis B, HBsAg disappears by definition within six months. A longer persistence of HBsAg is considered a marker for chronic HBV infection. Infection of newborns or infants typically results in a persistent infection because for unknown reasons an effective immune response does not begin for years or decades. Infection of immunocompromised patients also leads to persistence even if the immune impairment is mild as in hemodialysis patients. However, after a long anergic phase, immune defense may emerge and lead to selection of escape mutants. As soon as cellular immune responses against HBcAg appear, HBeAg has lost its immunomodulatory function and is a useless side product. HBeAg-negative variants with enhanced HBcAg expression and viral replication usually take over and partially compensate for the loss of destroyed HBV infected cells. Variants with mutated T cell epitopes of HBcAg and HBsAg may be selected, non-essential epitopes of the preS domain may be deleted. The main point is now whether the immune response is strong enough to keep HBV DNA replication low. If so, the course may be benign although expression of HBsAg may still occur . Finally, the immune control will even suppress HBsAg to undetectable levels in many chronic carriers. On the opposite, co-existence of cytotoxic immune responses with ongoing strong HBV DNA replication results in inflammatory disease, progressive fibrosis of the liver and potentially in hepatocellular carcinoma.

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Treatment Options For Antiviral Resistant Pathogens

If a virus is not fully wiped out during a regimen of antivirals, treatment creates a bottleneck in the viral population that selects for resistance, and there is a chance that a resistant strain may repopulate the host. Viral treatment mechanisms must therefore account for the selection of resistant viruses.

The most commonly used method for treating resistant viruses is combination therapy, which uses multiple antivirals in one treatment regimen. This is thought to decrease the likelihood that one mutation could cause antiviral resistance, as the antivirals in the cocktail target different stages of the viral life cycle. This is frequently used in retroviruses like HIV, but a number of studies have demonstrated its effectiveness against influenza A, as well. Viruses can also be screened for resistance to drugs before treatment is started. This minimizes exposure to unnecessary antivirals and ensures that an effective medication is being used. This may improve patient outcomes and could help detect new resistance mutations during routine scanning for known mutants. However, this has not been consistently implemented in treatment facilities at this time.

Pregnant Women At Risk For Infection Or An Adverse Infection

Lin and Vickery searched for large, high-quality studies related to hepatitis B screening in pregnancy that have been published since the 2004 USPSTF recommendation. English-language studies indexed in PubMed and the Cochrane Database of Systematic Reviews and published between January 1, 2001 and March 5, 2008 were included in this study. For benefits of screening and newborn prophylaxis, these investigators included systematic reviews meta-analyses and RCTs. For harms of screening, they included systematic reviews meta-analyses RCTs cohort studies case-control studies and case series of large, multi-site databases. Abstracts and full articles were independently reviewed for inclusion by both reviewers. Data on the benefits of screening, including benefits of hepatitis B immune globulin and hepatitis B vaccine prophylaxis of newborns of HBsAg-positive mothers, were extracted by 1 reviewer. No new studies met inclusion criteria. A 2006 systematic review of RCTs found that newborn prophylaxis reduced peri-natal transmission of HBV infection all relevant trials were published in 1996 or earlier. The authors concluded that no new evidence was found on the benefits or harms of screening for HBV infection in pregnant women. Previously published RCTs support the 2004 USPSTF recommendation for screening.

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Treatment Methods And Observation Indicators

Treatment Methods:

The patients in Group A received a 20 g/time injection of recombinant Saccharomyces cerevisiae-derived hepatitis B vaccine subcutaneously/intramuscularly at weeks 0, 4, and 24, according to standard vaccination procedures. Patients in Group B served as blank control.

Observation Indicators:

At weeks 0, 12, 24, and 36, the patients were observed, and the following data were collected: 1) Epidemiological and clinical information, such as a family history of hepatitis B, clinical symptoms, and signs. 2) Biochemistry, including blood tests, liver function , renal function, and AFP. 3) Virological indicators: serum HBV DNA, HBcrAg, HBsAg, HBeAg, anti-HBs, anti-HBe, and anti-HBc 4) Immunological indicators: total lymphocytes , CD3+T, CD4+T, CD8+T, and B lymphocytes in peripheral blood 5) Imaging data: color Doppler ultrasound of the upper abdomen/CT enhanced scan/MRI enhanced scan, liver transient elastography, and liver fat content detection. .

Persons With Chronic Diseases

Vaccine, Hepatitis B, Engerix

Refer to Immunization of Persons with Chronic Diseases in Part 3 for additional general information about vaccination of people with chronic diseases.

Chronic renal disease and patients on dialysis

People with chronic renal disease may respond sub-optimally to HB vaccine and experience more rapid decline of anti-HBs titres, and are therefore recommended immunization with a higher vaccine dose. Individuals undergoing chronic dialysis are also at increased risk for HB infection. In people with chronic renal disease anti-HBs titre should be evaluated annually and booster doses using a higher vaccine dose should be given as necessary.

Neurologic disorders

People with conditions such as autism spectrum disorders or demyelinating disorders should receive all routinely recommended immunizations, including HB-containing vaccine.

Chronic liver disease

HB immunization is recommended for non-immune persons with chronic liver disease, including those infected with hepatitis C, because they are at risk of more severe disease if infection occurs. Vaccination should be completed early in the course of the disease, as the immune response to vaccine is suboptimal in advanced liver disease. Post-immunization serologic testing may be used to confirm vaccine response.

Non-malignant hematologic disorders

Persons with bleeding disorders and other people receiving repeated infusions of blood or blood products are considered to be at higher risk of contracting HB and should be offered HB vaccine.

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Study Population And Setting

In the Islamic Republic of Iran, which has a population of 80 million, public health services are delivered through a nation-wide network. The public sector offers primary, secondary, and tertiary health services for the whole country population. The focus of the government on primary health care over the last three decades has made the public sector the main provider of primary health care services throughout the country. Some primary health care services such as prenatal care and vaccination programs are provided free of charge in public health care systems. Shiraz is the capital of Fars province in southern Iran with a population of 1,400,000, in the urban area and 650,000, in rural parts. In the urban area, nearly 100% of the population has been immunized with precise registries of vaccination data.1919 World Health Organization . WHO vaccine-preventable diseases: monitoring system.global summary. Available on-line at, http://apps.who.int/immunization_monitoring/globalsummary/countries?countrycriteria%5Bcountry%5D%5B%5D=IRN.

Other Reported Adverse Events And Conditions

While serious events and chronic illnesses such as chronic fatigue syndrome, multiple sclerosis, Guillain-Barré syndrome, rheumatoid arthritis and sudden infant death syndrome have been alleged or reported following HB vaccination, no evidence of a causal association has been demonstrated in a number of studies.

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Antiviral Medication For Hepatitis B

Doctors may recommend antiviral medication for people with chronic hepatitis B, which occurs when the virus stays in your body for more than six months.

Antiviral medication prevents the virus from replicating, or creating copies of itself, and may prevent progressive liver damage. Currently available medications can treat hepatitis B with a low risk of serious side effects.

NYU Langone hepatologists and infectious disease specialists prescribe medication when they have determined that without treatment, the hepatitis B virus is very likely to damage the liver over time. People with chronic hepatitis B may need to take antiviral medication for the rest of their lives to prevent liver damage.

There are many different types of antiviral medications available, and your doctor recommends the right type for you based on your symptoms, your overall health, and the results of diagnostic tests. A doctor may take a wait-and-see approach with a person who has a healthy liver and whose blood tests indicate a low viral load, the number of copies of the hepatitis B virus in your bloodstream.

Someone with HIV infection or AIDS may have a weakened immune system and is therefore more likely to develop liver damage. The U.S. Centers for Disease Control and Prevention strongly recommends that people with HIV infection who are diagnosed with hepatitis B immediately begin treatment with antiviral medication.

How Many People Have Hepatitis B

Jan 12, 2022 ACIP Meeting – Hepatitis Vaccines

In the United States, an estimated 862,000 people were chronically infected with HBV in 2016. New cases of HBV infection in the United States had been decreasing until 2012. Since that time, reported cases of acute hepatitis B have been fluctuating around 3,000 cases per year. In 2019, 3,192 cases of acute hepatitis B were reported however, because of low case detection and reporting, the Centers for Disease Control and Prevention estimates that there were 20,700 acute hepatitis B infections. New HBV infections are likely linked to the ongoing opioid crisis in the United States.

Globally, HBV is the most common blood-borne infection with an estimated 296 million people infected according to the World Health Organization .

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Hbv Vaccination Doses And Formulations

Given differences in the manufacturing processes and populations vaccinated, the quantity of HBsAg protein per dose that will induce a protective immune response differs in various vaccine products. Currently, hepatitis B vaccines are formulated to contain 540 g of recombinant HBsAg protein and an aluminum phosphate or aluminum hydroxide adjuvant . In general, based on immunogenicity data with different vaccine dosages in different age groups, the vaccine dosages to provide protection for infants, children, and adolescents are 50% lower than that required for adults . Marketed hepatitis B vaccines are to be administered by intramuscular injection on the anterolateral site of the thigh or into the deltoid muscle . The WHO has developed recommendations to ensure the quality, safety, and efficacy of recombinant hepatitis B vaccines and keeps a list of current hepatitis B vaccines prequalified by the WHO .

Hepatitis B vaccines are available as monovalent formulations for birth doses or for vaccination of adult persons at risk, and as combination vaccines . Major progress in the global response to viral hepatitis has been achieved through the introduction of routine hepatitis B vaccination via the WHOs Expanded Programme on Immunization, which was facilitated by the introduction of combination vaccines . Hepatitis B vaccines are generally stable for 3 to 4 years from the date of manufacture if stored between 2°C and 8°C.

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