USMLE Forum Archives - USMLE Step 3 - Pr Med: Varicella Zoster
Pr Med: Varicella Zoster
meduploader - 05-16-09 13:40
Causes Chickenpox and Herpes Zoster
Chicken pox – primary infection. Shingles is an activation of latent virus
Varicella Vaccine
Popular brand – Varivax
Live virus vaccine
Indications ( CDC 1999)
Children > 1 year of age without prior infection
In adults who never have been vaccinated or never had chicken pox- for Post chicken pox exposure vaccination within 3-5 days à can reduce the incidence of chickenpox
Non Pregnant women of childbearing age who are not immune (Pregnant women should wait until after they give birth to receive the vaccine. Women should not get pregnant until four weeks after the vaccine)
Susceptible family members and other contacts of HIV-infected or immunodeficient persons should receive the chickenpox vaccine, because of the risk that natural chickenpox and its complications present for these patients.
persons who live or work in environments in which transmission of VZV is likely (e.g., teachers of young children)
day care employees, and residents and staff members in institutional settings)
persons who live and work in environments in which transmission can occur (e.g., college students, inmates and staff members of correctional institutions, and military personnel)
international travelers
adolescents and adults living in households with children.
CDC (2007) à RECOMMENDS VACCINATION FOR ALL ADULTS AND ADOLESCENTS WITHOUT EVIDENCE OF IMMUNITY ( Check antibody, if not present just immunize)
Many states have mandatory requirement of chicken pox immunization prior to attending child care centers, students in all grade levels, persons attending college or other postsecondary educational institutions à evidence of immunization needs to be submitted before entering the institution eg: evidence of immunity includes – see next slide
Evidence of immunity includes
Documentation of two doses of varicella vaccine
Blood tests that show you are immune to varicella or laboratory confirmation of prior disease
Born in the United States before 1980, excluding health-care workers, pregnant women, and immunocompromised persons. These individuals need to meet one of the other criteria for evidence of immunity.
Receipt from a healthcare provider of a) a diagnosis of chickenpox or b) verification of a history of chickenpox
Receipt from a healthcare provider of a) a diagnosis of herpes zoster (shingles) or b) verification of a history of herpes zoster (shingles).
No need for the chickenpox vaccine, if any of the above criteria for evidence of immunity is met
Varicella Vaccine
in pregnancy ( to prevent congenital varicella). Also, women should not get pregnant for four weeks following vaccination
Anaphylactic reaction to neomycin
Active Tuberculosis.
Should not be given for 5 months following the receipt of antibody-containing (e.g., blood transfusion) products ( as it can inactivate vaccine virus)
Hx of congenital immune deficiency in a first degree relative
Immunosuppressed patients eg: AIDS (remember mild HIV is not a contraindication. Should be considered for HIVinfected children with age specific CD4+ T-lymphocyte lymphocyte percentages >15% and may also be considered in adults with CD4 > 200), high dose steroids
May be safe in Lactation
Realize that low grade fever, pregnant family member are not a contraindication
Vaccine protocol ( CDC – 2007 recommendations require 2 doses for all age groups listed)
Age under 13 years – Administer 2 doses recommended
- 1st dose at age 12–15 months
- 2nd dose at age 4–6 years
If giving after age over 13 years – give 2 doses , 4–8 weeks apart
If giving in early HIV – give 2 doses 3 months apart
VZIG
Varicella zoster immune globulin (VZIG) used to prevent disease after exposure to chickenpox à But it is costly and only provides temporary protection à hence, VZIG is recommended only for those at high risk of developing severe disease who are not eligible to receive chickenpox vaccine. (All other patients should get varivax in 3-5 days post exposure) The groups that cannot get Varivax and hence, the need for VZIG :
Newborns whose mothers have developed chickenpox 5 days prior to 2 days after delivery ( un vaccinated newborns of these mothers may develop fatal varicella)
Premature babies exposed to varicella in the first month of life
Children with leukemia or lymphoma who have not been vaccinated
Persons with cellular immunodeficiencies or other immune system problems eg: Advanced HIV
Persons receiving immunosuppressive medications – high dose steroids, immunosuppressants etc
Pregnant women
VZIG à best effective only if given within 96 hrs of exposure to Varicella (chickenpox) or to Zoster. Rx after 96 hrs is of uncertain value.
Varicella vaccine and VZIG never given together ( varicella is a live vaccine and will be ineffective)
Contraindications : hx of prior serious reaction to human immunoglobulin or severe thrombocytopenia
Varicella Zoster Vaccine
Popular brand – Zostavax
A live attenuated vaccine of VZV
Indicated in elderly patients age equal to or greater than 60 to prevent herpes zoster and to reduce its sequelae such as post herpetic neuralgia.
Dose : given 0.65ml sub cutaneous in deltoid
Contraindications : ( Realize that the virus load injected here is 14 times greater than in Varivax)
Hx of anaphylactic reaction to Gelatin, Neomycin or any other vaccine components.
Hx of immunodeficiency eg: leukemia, lymphoma, advanced HIV
Persons with active, untreated tuberculosis
Persons receiving immunosuppressive therapy, including high dose steroids.
Concomitant acute febrile illness with fever > 102
Side effects : Rash similar to chicken pox or Shingles can commonly occur after vaccine.
Immunity lasts for 4 years
VZV vaccine – Why important?
Vaccine reduces incidence of herpes zoster by 50% ( Number needed to treat = 60 i.e; 60 patients need to be treated to prevent one case. NNT = 1/incidence à so realize that higher incidence can mean lower NNT, making the successful intervention more cost effective.) à so, since shingles is more common in age > 60, vaccine is most cost effective in this age group.
Post herpetic neuralgia is the most debilitating complication of Herpes Zoster à VZV vaccine reduces PHN by 66% ( NNT = 360)
meduploader - 05-16-09 13:40
Causes Chickenpox and Herpes Zoster
Chicken pox – primary infection. Shingles is an activation of latent virus
Varicella Vaccine
Popular brand – Varivax
Live virus vaccine
Indications ( CDC 1999)
Children > 1 year of age without prior infection
In adults who never have been vaccinated or never had chicken pox- for Post chicken pox exposure vaccination within 3-5 days à can reduce the incidence of chickenpox
Non Pregnant women of childbearing age who are not immune (Pregnant women should wait until after they give birth to receive the vaccine. Women should not get pregnant until four weeks after the vaccine)
Susceptible family members and other contacts of HIV-infected or immunodeficient persons should receive the chickenpox vaccine, because of the risk that natural chickenpox and its complications present for these patients.
persons who live or work in environments in which transmission of VZV is likely (e.g., teachers of young children)
day care employees, and residents and staff members in institutional settings)
persons who live and work in environments in which transmission can occur (e.g., college students, inmates and staff members of correctional institutions, and military personnel)
international travelers
adolescents and adults living in households with children.
CDC (2007) à RECOMMENDS VACCINATION FOR ALL ADULTS AND ADOLESCENTS WITHOUT EVIDENCE OF IMMUNITY ( Check antibody, if not present just immunize)
Many states have mandatory requirement of chicken pox immunization prior to attending child care centers, students in all grade levels, persons attending college or other postsecondary educational institutions à evidence of immunization needs to be submitted before entering the institution eg: evidence of immunity includes – see next slide
Evidence of immunity includes
Documentation of two doses of varicella vaccine
Blood tests that show you are immune to varicella or laboratory confirmation of prior disease
Born in the United States before 1980, excluding health-care workers, pregnant women, and immunocompromised persons. These individuals need to meet one of the other criteria for evidence of immunity.
Receipt from a healthcare provider of a) a diagnosis of chickenpox or b) verification of a history of chickenpox
Receipt from a healthcare provider of a) a diagnosis of herpes zoster (shingles) or b) verification of a history of herpes zoster (shingles).
No need for the chickenpox vaccine, if any of the above criteria for evidence of immunity is met
Varicella Vaccine
in pregnancy ( to prevent congenital varicella). Also, women should not get pregnant for four weeks following vaccination
Anaphylactic reaction to neomycin
Active Tuberculosis.
Should not be given for 5 months following the receipt of antibody-containing (e.g., blood transfusion) products ( as it can inactivate vaccine virus)
Hx of congenital immune deficiency in a first degree relative
Immunosuppressed patients eg: AIDS (remember mild HIV is not a contraindication. Should be considered for HIVinfected children with age specific CD4+ T-lymphocyte lymphocyte percentages >15% and may also be considered in adults with CD4 > 200), high dose steroids
May be safe in Lactation
Realize that low grade fever, pregnant family member are not a contraindication
Vaccine protocol ( CDC – 2007 recommendations require 2 doses for all age groups listed)
Age under 13 years – Administer 2 doses recommended
- 1st dose at age 12–15 months
- 2nd dose at age 4–6 years
If giving after age over 13 years – give 2 doses , 4–8 weeks apart
If giving in early HIV – give 2 doses 3 months apart
VZIG
Varicella zoster immune globulin (VZIG) used to prevent disease after exposure to chickenpox à But it is costly and only provides temporary protection à hence, VZIG is recommended only for those at high risk of developing severe disease who are not eligible to receive chickenpox vaccine. (All other patients should get varivax in 3-5 days post exposure) The groups that cannot get Varivax and hence, the need for VZIG :
Newborns whose mothers have developed chickenpox 5 days prior to 2 days after delivery ( un vaccinated newborns of these mothers may develop fatal varicella)
Premature babies exposed to varicella in the first month of life
Children with leukemia or lymphoma who have not been vaccinated
Persons with cellular immunodeficiencies or other immune system problems eg: Advanced HIV
Persons receiving immunosuppressive medications – high dose steroids, immunosuppressants etc
Pregnant women
VZIG à best effective only if given within 96 hrs of exposure to Varicella (chickenpox) or to Zoster. Rx after 96 hrs is of uncertain value.
Varicella vaccine and VZIG never given together ( varicella is a live vaccine and will be ineffective)
Contraindications : hx of prior serious reaction to human immunoglobulin or severe thrombocytopenia
Varicella Zoster Vaccine
Popular brand – Zostavax
A live attenuated vaccine of VZV
Indicated in elderly patients age equal to or greater than 60 to prevent herpes zoster and to reduce its sequelae such as post herpetic neuralgia.
Dose : given 0.65ml sub cutaneous in deltoid
Contraindications : ( Realize that the virus load injected here is 14 times greater than in Varivax)
Hx of anaphylactic reaction to Gelatin, Neomycin or any other vaccine components.
Hx of immunodeficiency eg: leukemia, lymphoma, advanced HIV
Persons with active, untreated tuberculosis
Persons receiving immunosuppressive therapy, including high dose steroids.
Concomitant acute febrile illness with fever > 102
Side effects : Rash similar to chicken pox or Shingles can commonly occur after vaccine.
Immunity lasts for 4 years
VZV vaccine – Why important?
Vaccine reduces incidence of herpes zoster by 50% ( Number needed to treat = 60 i.e; 60 patients need to be treated to prevent one case. NNT = 1/incidence à so realize that higher incidence can mean lower NNT, making the successful intervention more cost effective.) à so, since shingles is more common in age > 60, vaccine is most cost effective in this age group.
Post herpetic neuralgia is the most debilitating complication of Herpes Zoster à VZV vaccine reduces PHN by 66% ( NNT = 360)
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Re: Pr Med: Varicella Zoster mtniharika - 10-05-09 15:38 an exhaustive information....
varicella vaccine is a very safe and effective vaccine...Possible side effects are generally mild and include redness, stiffness, and soreness at the injection site. the only consideration is the development of shingles in the elderly(herpes zoster).
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