# Presentation: 064986

## Varicella and Varicella Vaccine

**Epidemiology and Prevention of Vaccine-Preventable Diseases**
**National Immunization Program**
**Centers for Disease Control and Prevention**

**Revised December 2004**

## Note to presenters:

**Images of vaccine-preventable diseases are available from the Immunization Action Coalition website at ****http://www.vaccineinformation.org/photos/index.asp**

## Varicella

**Acute viral illness**
**Zoster described in premedieval times**
**Varicella not differentiated from smallpox until end of 19th century**
**Infectious nature demonstrated in 1875**

## Varicella Zoster Virus

**Herpesvirus (DNA)**
**Primary infection results in varicella (chickenpox)**
**Recurrent infection results in herpes zoster (shingles)**
**Short survival in environment **

## Varicella Pathogenesis

**Respiratory transmission of virus**
**Replication in nasopharynx and regional lymph nodes**
**Repeated episodes of viremia**
**Multiple tissues, including sensory ganglia, infected during viremia**

## Varicella Clinical Features

**Incubation period 14-16 days (range 10-21 days)**
**Mild prodrome for 1-2 days**
**Generally appear first on head; most concentrated on trunk**
**Successive crops (2-4 days) of pruritic vesicles**** **

## Herpes Zoster

**Reactivation of varicella zoster virus**
**Associated with:**
** ****aging**
** ****immunosuppression**
** ****intrauterine exposure**
** ****varicella at <18 month of age**

## Varicella Complications

**Bacterial infection of lesions**
**CNS manifestations**
**Pneumonia (rare in children)**
**Hospitalization ~3 per 1,000 cases**
**Death ~1 per 60,000 cases**

## Groups at Increased Risk of Complications of Varicella

**Healthy adults**
**Immunocompromised persons**
**Newborns of mothers with rash onset within 5 days before to 48 hours after delivery**

## Varicella Fatality Rate in Healthy Persons

***Deaths per 100,000 cases**

## Congenital Varicella Syndrome

**Results from maternal infection during pregnancy**
**Period of risk may extend through first 20 weeks of pregnancy**
**Atrophy of extremity with skin scarring, low birth weight, eye and neurologic abnormalities**
**Risk appears to be small (< 2%)**

## Varicella Laboratory Diagnosis

**Isolation of varicella virus from clinical specimen**
**Rapid varicella virus identification using direct fluorescent antibody (DFA) testing**
**Significant rise in varicella IgG by any standard serologic assay (e.g., enzyme immunoassay)**

## Varicella Epidemiology

**Reservoir****	****	**** Human**** **
**Transmission****	****	**** Airborne droplet****	****	****	****	**** Direct contact with lesions**
**Temporal pattern****	**** Peak in winter–early****	****	****	****	**** spring (U.S.)****	****	****	**
**Communicability****	**** 1-2 days before to 4-5****	****	****	****	**** days after onset of rash****	****	****	****	**** May be longer in****	****	****	****	****	****  ****	**** immunocompromised**

## Varicella Age-Specific Incidence United States, 1990-1994

***Rate per 100,000 population.  National Health Interview Survey data**

## Active Varicella Surveillance

**3 sites conducting active surveillance for varicella since 1995**
**Combined population 1.2 million**
**Combined birth cohort 21,000**
**2000 varicella vaccine coverage 74%-84%**

**Seward JF, et al.  JAMA 2002;287:606-11**

**Notes:**
Travis County (Austin), TX, West Philadelphia, Antelope Valley, CA

## Varicella Cases by Month -- Antelope Valley, CA, 1995–2002

**1995**

**1997**

**1998**

**1996**

**1999**

**2000**

**2001**

**2002**

## Reduction of Reported Varicella by Age, Active Surveillance Sites, 1995 to 2001

- _Age_

- Antelope
- _Valley, CA_

- West
- _Phila., PA_

- Travis _County, TX*_

**< 1 year**

**73%**

**87%**

**87%**

**1–4 years**

**88%**

**91%**

**87%**

**5–9 years**

**71%**

**80%**

**87%**

**10–14 years**

**51%**

**78%**

**89%**

**15–19 years**

**60%**

**85%**

**78%**

_**>**_**20 years**

**77%**

**74%**

**54%**

**Overall**

**76%**

**86%**

**86%**

**------------Surveillance Area------------**

***Travis County: 1995 vs. 2000**

## Varicella Vaccine

**Composition****	****	****Live virus (Oka/Merck strain)**
**Efficacy****	****	****	****95%  (Range, 65%-100%)**** **
**Duration of ****	****	****>7 years****Immunity**** **
**Schedule****	****	****1 Dose (<13 years of age)****May be administered simultaneously with measles-mumps-rubella (MMR) vaccine**

## Breakthrough Infection

**Immunity appears to be longlasting for most recipients**
**Breakthrough disease much milder than in unvaccinated persons**
**No consistent evidence that risk of breakthrough infection increases with time since vaccination**

## Breakthrough Infection

**Retrospective cohort study of 115,000 children vaccinated in 2 HMOs during January 1995 through December 1999**
**Risk of breakthrough varicella 2.5 times higher if varicella vaccine administered less than 30 days following MMR**
**No increased risk if varicella vaccine given simultaneously or more than ****30 days after MMR**

***MMWR***** 2001;50(47):1058-61**

## Varicella Vaccine RecommendationsChildren

**Routine vaccination at 12-18 months of age**
**Recommended for all susceptible children by the 13th birthday**

## Varicella Vaccine RecommendationsAdolescents and Adults

**Persons **_**>**_**13 years of age without history of varicella**
**Two doses separated by 4-8 weeks**
**Up to 90% of adults immune**
**Serologic testing may be cost-effective**

## Varicella Vaccine RecommendationsAdolescents and Adults

**Susceptible persons at high risk of exposure or severe illness**
** ****Teachers of young children**
** ****Institutional settings**
** ****Military**
** ****Women of childbearing age**
** ****International travelers**** **

## Varicella Vaccine RecommendationsAdolescents and Adults

**Susceptible persons likely to expose persons at high risk for severe illness**
** ****Healthcare workers**
** ****Family members of immuno-****	****  compromised persons**

## Vaccination of Healthcare Workers

**Recommended for all susceptible healthcare workers**
**Prevaccination serologic screening probably cost-effective**
**Postvaccination testing not necessary or recommended**

## Varicella VaccinePostexposure Prophylaxis

**Varicella vaccine is recommended for use in susceptible persons after exposure to varicella**
**70%-100% effective if given within 72 hours of exposure**
**not effective if >5 days but will produce immunity if not infected**

## Varicella Vaccine Adverse Reactions

**Injection site complaints – 20%**
**Rash – 3%-4%**
**May be maculopapular rather****than vesicular**
**Average 5 lesions**
**Systemic reactions not common**

## Zoster Following Vaccination

**Most cases in children**
**Risk from vaccine virus less than from wild virus**
**Usually a mild illness without complications**

## Varicella VaccineContraindications and Precautions

**Severe allergic reaction to vaccine component or following prior dose**
**Pregnancy**
**Immunosuppression**
**Moderate or severe acute illness**
**Recent blood product**

## Varicella Vaccination in Pregnancy Registry

- 800.986.8999

## Varicella VaccineUse in Immunocompromised Persons

**Most immunocompromised persons should not be vaccinated**
**Vaccinate persons with isolated humoral immunodeficiency**
**Consider varicella vaccination for asymptomatic HIV-infected children with CD4% >25% (CDC class A1 and N1)**

## Transmission of Varicella Vaccine Virus

**Transmission of vaccine virus not common**
**Asymptomatic seroconversion may occur in susceptible contacts**
**Risk of transmission increased if vaccinee develops rash**

## Vaccine Storage and Handling

**Store frozen at +5****°****F (-15****°****C ) or lower**
**Generally should not be refrozen**
**Store diluent at room temperature or refrigerate**
**Discard if not used within 30 minutes of reconstitution**

## Varicella Vaccine Information

- 800-9VARIVAX

## Varicella Zoster Immune Globulin (VZIG)

**May modify or prevent disease if given <96 hours after exposure**
**Indications**
**immunocompromised persons**
**newborn of mothers with onset 5 days before to 48 hours after birth**
**premature infants with postnatal exposure**
**susceptible adults and pregnant women**

## Varicella Antiviral Therapy

**Not recommended for routine use among otherwise healthy infants and children with varicella**
**Consider for persons age >13 years**
**Consider for persons with chronic cutaneous or pulmonary disorders, long-term salicylate therapy, or steroid therapy**
**IV in immunocompromised children and adults with viral-mediated complications**
**Not recommended for post-exposure prophylaxis**

**2003 AAP Red Book**

## National Immunization Program

**Hotline****	****	****800.232.2522**** **
**Email****	****	****nipinfo@cdc.gov**** **
**Website****	****	****www.cdc.gov/nip**