HERPES ZOSTER VACCINE

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HERPES ZOSTER VACCINE
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Behavioral Objectives

• Discuss the pathogenesis of Herpes Zoster.
• Discuss the benefits of immunizing the elderly
  with Zostavax vaccine.
• Describe how genetic reassortment is used to make
  rotavirus vaccine.
• Discuss the recommendations, precautions and
  contra-indications for the use of rotavirus
  vaccine.

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Varicella Zoster Virus

• Herpes virus
• Primary infection results in varicella
  (chickenpox)
• Recurrent infection results in herpes zoster
  (shingles)
• Short survival in environment

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Herpes Zoster (Shingles)

• Reactivation of varicella zoster virus
• Can occur years or even decades after illness
  with chickenpox
• Generally associated with normal aging and with
  anything that causes reduced immunocompetence
• Lifetime risk of 20 percent in the United States
• Estimated 500,000- 1 million cases of zoster
  diagnosed annually in the U.S

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Varicella Vaccines

• All three vaccines contain the same live
  Oka-Merck varicella vaccine virus but in
  different concentrations
• Varivax - 1,400 pfu
• ProQuad - 9,800 pfu (7x Varivax)
• Zostavax - 19,000 pfu (14x Varivax)

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Herpes Zoster Vaccine (Zostavax)

• Contains the same live attenuated varicella virus
  as Varivax but at a much higher titer of vaccine
  virus
• Approved by FDA for persons 60 years of age and
  older
• Administered by the subcutaneous route

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Herpes Zoster Vaccine Efficacy

• Compared to the placebo group the vaccine group
  had
• 51 fewer episodes of zoster
• Less severe disease
• 66 less postherpetic neuralgia
• No significant safety issues were identified

NEJM 2005352(22)2271-84.
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Herpes Zoster Vaccine

• Approved for a single dose among persons 60 years
  and older whether or not they report a prior
  episode of shingles
• Persons with a chronic medical condition may be
  vaccinated unless a contraindication or
  precaution exists for the condition

provisional recommendations as of January 2007
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Herpes Zoster VaccineStorage and Handling

• Store frozen at 5F (-15C ) or lower at all
  times
• Protect from light
• Discard if not used within 30 minutes of
  reconstitution

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• Rotavirus and Rotavirus Vaccine

Epidemiology and Prevention of Vaccine-Preventable
Diseases National Immunization Program Centers
for Disease Control and Prevention
Revised January 2007
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Rotavirus

• First identified as cause of diarrhea in 1973
• Most common cause of severe diarrhea in infants
  and children
• Nearly universal infection by 5 years of age
• Responsible for up to 500,000 diarrheal deaths
  each year worldwide

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Rotavirus

• Reovirus (RNA)
• VP7 and VP4 antigens define virus serotype and
  induce neutralizing antibody
• 5 predominant strains in U.S. (G1-G4, G9) and
  account for 90 of isolates
• Strain G1 accounts for 73 of infections
• Very stable and may remain viable for weeks or
  months if not disinfected

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Rotavirus Pathogenesis

• Entry through mouth
• Replication in epithelium of small intestine
• Replication outside intestine and viremia
  uncommon
• Infection leads to isotonic diarrhea

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Rotavirus Immunity

• Antibody against VP7 and VP4 probably important
  for protection
• First infection usually does not lead to
  permanent immunity
• Reinfection can occur at any age
• Subsequent infections generally less severe

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Rotavirus Clinical Features

• Incubation period 1-3 days
• Clinical manifestations depend on whether it is
  the first infection or reinfection
• First infection after age 3 months generally most
  severe
• May be asymptomatic or result in severe
  dehydrating diarrhea with fever and vomiting
• Gastrointestinal symptoms generally resolve in 3
  to 7 days

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Rotavirus Complications

• Severe diarrhea
• Dehydration
• Electrolyte imbalance
• Metabolic acidosis
• Immunodeficient children may have more severe or
  persistent disease

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Rotavirus Disease Burden in the United States

• Estimated 2.7 million cases per year
• 95 of children infected by 5 years of age
• The most severe disease occurs among children
  3-24 months of age
• Highest incidence among children 3 to 35 months
  of age
• Responsible for 5-10 of all gastroenteritis
  episodes among children younger than 5 years of
  age

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Rotavirus Disease in the United States

• Annually responsible for
• More than 400,000 physician visits
• More than 200,000 emergency dept visits
• 55,000-70,000 hospitalizations
• 20-60 deaths
• Annual direct and indirect costs are estimated at
  approximately 1 billion

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Rotavirus Epidemiology

• Reservoir Human-GI tract
• Transmission Fecal-oral, fomites
• Temporal Fall and winter pattern (temperate
  areas)
• Communicability 2 days before to 10 days
  after onset

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Risk Groups for Rotavirus Diarrhea

• Groups with increased exposure to virus
• Children in child care centers
• Children in hospital wards (nosocomial rotavirus)
• Caretakers, parents of these children
• Children, adults with immunodeficiency related
  diseases (e.g. SCID, HIV, bone marrow transplant)

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Rotavirus Vaccine

• Created by genetic reassortment
• Causes nonhuman rotavirus strains to express
  human rotavirus antigens on their surface
• Nonhuman rotaviruses have low pathogenicity
  for humans
• Replicate but do not cause disease

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Rotavirus Vaccine (Rota)
Human
Animal
Reassortant
Tissue Culture
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Rotavirus Vaccine (RotaTeq)

• Approved by FDA in February 2006
• Contains five reassortant rotaviruses developed
  from human and bovine parent rotavirus strains
• Vaccine viruses suspended in a solution of buffer
  (sodium citrate and phosphate) and stabilizer
• Contains no preservatives or thimerosal

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Rotavirus Vaccine Efficacy

• Phase III trials included more than 70,000
  infants in 11 countries
• Efficacy
• All rotavirus disease - 74
• Severe rotavirus disease - 98
• Physician visits for diarrhea-86 reduction
• Rotavirus-related hospitalization-96 reduction
• Efficacy of fewer than 3 doses is not known

N Eng J Med 200635423-33
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Rotavirus VaccineRecommendations

• Routine immunization of all infants without
  contraindications
• Administered at 2, 4, and 6 months of age
• Minimum age of first doses is 6 weeks
• First dose should be administered between 6 and
  12 weeks of age (until age 13 weeks)
• Do not initiate series after 12 weeks of age

MMWR 200655(RR-12)1-13.
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Rotavirus VaccineRecommendations

• Minimum interval between doses is 4 weeks
• Maximum age for ANY dose is 32 weeks
• Do not administer on or after age 32 weeks, even
  if fewer than three doses have been administered

MMWR 200655(RR-12)1-13.
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Rotavirus VaccineRecommendations

• Administer simultaneously with all other
  indicated vaccines
• Breastfeeding infants should be vaccinated on
  usual schedule
• Vaccinate infants who have recovered from
  documented rotavirus infection
• Do not repeat dose if infant spits out or
  regurgitates vaccine- administer remaining doses
  on schedule

MMWR 200655(RR-12)1-13.
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Rotavirus Vaccine and Intussusception
Vaccine Recipients 6 cases 13 cases
Placebo Recipients 5 cases 15 cases
Within 42 days of vaccination Within 1 year of
vaccination
New Eng J Med 200635423-33
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Rotavirus VaccineAdverse Reactions

• Vomiting 15
• Diarrhea 24
• Nasopharyngitis 7
• Fever 43
• No serious adverse reactions reported

MMWR 200655(RR-12)1-13.
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Rotavirus VaccineContraindications

• Severe allergic reaction to a vaccine component
  or following a prior dose of vaccine

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Rotavirus VaccinePrecautions

• Altered immunocompetence
• Recent receipt of blood product
• Acute, moderate to severe gastroenteritis or
  other acute illness
• Pre-existing chronic GI disease
• Infants with history of intussusception

the decision to vaccinate if a precaution is
present should be made on a case-by-case risk and
benefit basis
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Rotavirus Vaccine and Preterm Infants

• Few data available
• ACIP supports the vaccination of a preterm infant
  if
• the infant is at least 6 weeks of age and
• is being or has been discharged from the
  hospital and
• is clinically stable

MMWR 200655(RR-12)1-13.
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Immunosuppressed Household Contacts of Rotavirus
Vaccine Recipients

• Protection of the immunocompromised household
  member afforded by vaccination of young children
  in the household outweighs the small risk for
  transmitting vaccine virus to the
  immunocompromised household member
• Household should employ measures such as good
  hand washing after contact with the feces of the
  vaccinated infant