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.
Despite their successes, in the United States there exists plenty of stigma surrounding vaccines that cause people to be incompletely vaccinated. These “gaps” in vaccination result in unnecessary infection, death, and costs. There are two major reasons for incomplete vaccination:
How Is The Hepatitis A And B Vaccine Given
- This vaccine is given as a course of two or three injections, depending on the brand of vaccine used. The injections are usually given over a period of six months, but an accelerated schedule given over one month is also possible.
- The injections are administered into the muscle of the upper arm in adults, adolescents and older children, and the thigh in younger children.
- If you’re at risk of bleeding after an injection into the muscle, for example if you have a blood clotting disorder such as haemophilia, or low levels of platelets in your blood , you may be given the injection under the skin rather than into the muscle. However, the vaccine may be less effective when administered this way.
- Some vaccines remain effective for a lifetime, while others have to be updated after a few years. This vaccine protects against hepatitis A for 10 years and hepatitis B for 5 years. A booster injection can be given 5 years after the first course to provide continued protection against both viruses. Alternatively, booster vaccines can be given separately hepatitis B after 5 years and hepatitis A after 10 years.
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:
Before cell entry
This stage of viral replication can be inhibited in two ways:
Inhibitors of uncoating have also been investigated.
During Viral Synthesis
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What Type Of Vaccine Is Hepatitis
There are two types of hepatitis A vaccine. The first type, the single-dose hepatitis A vaccine, is given as two shots, 6 months apart, and both shots are needed for long-term protection against hepatitis A. The other type is a combination vaccine that protects people against both hepatitis A and hepatitis B.
What Else Should I Know About Hepatitis B/hepatitis A Vaccine
What preparations of hepatitis B/hepatitis A vaccine are available?
- Hepatitis A/B vaccine is available as sterile, preservative-free, intramuscular injections.
- Hepatitis A/B vaccine injections are available in 1 ml single-dose vials and 1 ml single-dose pre-filled disposable syringes.
- Each 1 ml dose of vaccine contains 720 ELISA Units of inactivated Hepatitis A virus and 20 mcg of recombinant Hepatitis B antigen protein.
How should I keep hepatitis B/hepatitis A vaccine stored?
Store hepatitis A/B vaccine under refrigeration between 2 C and 8 C . Do not freeze hepatitis A/B vaccine vaccines and discard if they have been frozen.
Who Should Be Vaccinated With Hepatitis A
- Any person who desires protection from hepatitis A
- Men who have sex with men
- People who use injection or non-injection illegal drugs
- People traveling to areas with a high or intermediate occurrence of hepatitis A
- People with chronic liver disease
- People who receive clotting factor concentrates
- People working with HAV-infected primates or with HAV in a research laboratory
- People who will have close personal contact with an international adoptee during the first 60 days after arriving in the US from a country with a high or intermediate occurrence of hepatitis A
Who Should Get The Hepatitis B Vaccine
The CDC recommends it for all babies, who should get their first dose as newborns.
Other people who need it include:
- People younger than age 19 who haven’t been vaccinated
- Anyone who has a sex partner with hepatitis B
- People who are sexually active but arenât in a long-term relationship in which both partners are monogamous
- Anyone being evaluated or treated for an STD
- Men who have sex with men
- People who share needles used to inject drugs
- Anyone who lives with someone who has hep B
- Anyone whose job routinely puts them at risk for coming in contact with blood or blood-contaminated body fluids
- People with end-stage kidney disease
- People who live and work in facilities for people who are developmentally disabled
- Travelers to regions with moderate to high rates of hepatitis B
- People with chronic liver disease
- People with HIV infections
You should not get the vaccine if you had a severe allergic reaction to an earlier dose or are allergic to yeast, because yeast is used to make the vaccine.
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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.
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.
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Us Infant Hepatitis B Vaccine Schedules
*Please note that the first dose should be given as soon as possible. Additional doses require minimum time intervals between doses in order for the vaccine to be effective.
3-Dose Vaccine Series for Infants
Since 1991, ALL medically stable infants with a birth weight of at least 2,000 g in the U.S. are recommended to receive the first dose of hepatitis B vaccine within 24 hours of birth. The additional 2 doses are given at 1 month and 6 months of age.
4-Dose Vaccine Combination Series for Infants
Combination vaccines, such as the pentavalent and hexavalent vaccines, include protection against 5 or 6 diseases, including hepatitis B. The first shot is usually given at 6 weeks of age, but in order to protect infants from hepatitis B beginning at birth, a monovalent or single dose of the hepatitis B vaccine is also recommended within 24 hours of birth. The hepatitis B vaccine series can then be completed with the pentavalent or hexavalent vaccine with the recommended schedule.
Hepatitis A And B Vaccine
Twinrix is a vaccine against hepatitis A and hepatitis B, manufactured by GlaxoSmithKline Biologicals. The full generic name ishepatitis A inactivated & hepatitis B vaccine. 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, and Engerix-B, a recombinant Hepatitis B vaccine. Twinrix first entered the market in early 1997.
In the United States, Twinrix is approved by the Food and Drug Administration for those aged 18 and older. In some countries outside the United States, notably Canada and Europe, Twinrix is known as Twinrix Adult or Ambirix and a pediatric formulation, called Twinrix Junior or Twinrix Paediatric, is available.
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What Is The Hepatitis A And B Vaccine Used For
The hepatitis A and B vaccine is not given routinely. It is recommended for people who are at high risk of contracting both hepatitis A and B, for example:
- travellers to high risk areas
- laboratory staff who work directly with the viruses
- healthcare workers who have direct contact with blood or body fluids
- people with haemophilia
- people with severe liver disease
- people who are at risk due to their sexual behaviour
- staff and residents of homes for those with severe learning difficulties
- intravenous drug abusers.
Persons With Inadequate Immunization Records
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.
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What Is Hepatitis A
Hepatitis A is a liver infection caused by the hepatitis A virus. Unlike other forms of hepatitis, A is not a life-long infection. The majority of infections are in travellers.
The virus spreads through contaminated food and water. It is found in some of the most popular destinations like Mexico, Brazil and South Africa. But, a few hundred cases occur every year in Canada. Make sure youre protected at home and abroad with a vaccine against this disease.
Hepatitis A vaccination recommended for food service, healthcare and other fields where the infection could easily spread. Many hepatitis A outbreaks are linked to food service workers having the disease or not following proper precautions.
Visit our hepatitis A page to learn more.
Hepatitis A And B Vaccination
Effective and well-tolerated hepatitis A and B vaccines are available either as monovalent formulations or in various combinations. Although the benefits of a full primary vaccination course are clearprotection against potentially life-threatening diseasesthe requirement for a booster varies in different countries. Recommendations for the administration of hepatitis boosters in the United States, the United Kingdom, and Germany illustrate this. In the United States, a hepatitis B booster is not recommended for children and adults with a normal immune status , whereas in the United Kingdom, administration of a single booster dose 5 years after completion of the primary course is deemed necessary . In Germany, for example, Empfehlungen der Ständigen Impfkommission recommendations published in July 2004 state that immune response should be checked for persons who are immunodeficient and suggest the same for persons aged > 40 years. For persons with antihepatitis B surface antigen titers of < 100 mIU/mL, 1 extra dose is recommended, followed by an additional antibody test. In vaccinees with anti-HBs titers of > 100 mIU/mL, a booster is recommended after 10 years when the potential for risk continues . The World Health Organization has recognized that almost all children are protected against hepatitis B after vaccination, without a requirement for boosters, and that the protection is most likely lifelong .
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Hepatitis A & B Combination Vaccine
Hepatitis A & B combination vaccineHepatitis A & B Quick facts4 doses 0, 7, 2130 days and 12 months apart at least 21 days prior to travel
Hepatitis A and B are two viruses that affect your liver’s ability to function.
Hepatitis A is usually spread through ingesting contaminated food or water or close contact with an infected person. The hepatitis A virus can cause a flu-like illness, a yellowing of the skin or eyes along with severe stomach pains and diarrhea.
Hepatitis B is a highly contagious, serious liver disease caused by the hepatitis B virus. It spreads through contact with the blood or other body fluids of an infected person, including contact with objects that could have blood or body fluids on them such as toothbrushes and razors. It can cause a short-term flu-like illness, or long-term infection that can lead to liver damage, liver cancer or death. Babies and young children infected with hepatitis B are more likely to get this chronic form of the disease.
The hepatitis A & B combination vaccine contains both hepatitis A and hepatitis B vaccines to prevent these two forms of hepatitis. Its administered either as 3 doses over 6-month period or 3 shots administered over 1 month with the addition of a booster shot after 1 year.
Learn more about the hepatitis A & B vaccines from the CDC:
Will I Need A Hepatitis A/b Booster Shots
Like the hepatitis A and B vaccines, the hepatitis A/B vaccine does require booster shots to be fully effective. One booster is needed at a month and another after six months. A hepatitis A/B booster vaccines are not needed in order to travel as the vaccine is effective within two weeks of the first dose. But, the injections should be given for lifetime immunity to both hepatitis A and B.
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Study To Show That The Combined Hepatitis A And B Vaccine Is Non
|The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.|
|First Posted : January 29, 2008Last Update Posted : March 14, 2017|
|Biological: TwinrixBiological: Engerix-BBiological: HavrixBiological: HBVAXPROBiological: Vaqta||Phase 4|
|Study Type :|
|Official Title:||Evaluate the Effect of Risk Factors That Influence the Immunogenicity of GSK Biologicals’ Twinrix Compared to Hepatitis A and Hepatitis B Vaccines Given Separately and to Show the Non-inferiority Between the Vaccines in Adults|
|Study Start Date :|
Persons New To Canada
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.
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