RISK FACTORS:
β’ No prior history of varicella
β’ Immunosuppressed (especially children with leukemia / lymphoma in remission or on high-dose corticosteroids)
* - VZV is a common virus that carries risk for both mother and fetus during pregnancy. Morbidity and mortality rates are much higher in adults than in children. If the mother develops primary varicella during pregnancy, especially in the third trimester, she is at risk for varicella pneumonia. Subclinical infection also may play a role in neonatal morbidity (Mustonen, 2001). The mortality rate was 36%; the rate is now closer to 10%. Congenital varicella syndrome (CVS) results in spontaneous abortion, chorioretinitis, cataracts, limb atrophy, cerebral cortical atrophy, and neurological disability. Spontaneous abortion has been reported in 3-8% of first-trimester infections, and CVS has been reported in 12% (Sauerbrei, 2000). Acquisition of infection by the mother in the perinatal period poses a risk of severe neonatal varicella, with a mortality rate of 30%.
MEDICAL TT :
* - ACYCLOVIR IS DRUG OF CHOICE.
. Antipyretics for fever
. Avoid aspirin because of its link to Reye syndrome
. Local and/or systemic antipruritic agents for itching . In immunocompromised host - varicella-zoster immune
globulin (VZIG) available for passive immunization. VZIG must be given within 96 hours after exposure
to be benefi cial. After 4th day postexposure, wait for rash to develop then give acyclovir 500 mg/m2/day
intravenously every 8 hours for 7 days.
. Acyclovir - decreases duration of fever and shortens time of viral shedding. Recommended for adolescents,
adults and high-risk patients. Most benefi cial if initiated early in the disease (. 24 hours).
. 2-16 yr: 20 mg/kg/dose (max. 800 mg/dose), qid for 5 days
. Adults: 800 mg, 5 times daily.
ALTERNATIVE DRUGS:
β’ Famciclovir 500 mg tid x 7-10 days
β’ Valacyclovir 1 gm tid x 7-10 days
β’ Vidarabine
β’ Interferon
PATIENT MONITORING: Usually none in mild cases. If complications occur, intensive supportive
care may be required.
PREVENTION/AVOIDANCE:
. Exposed, susceptible individuals considered infectious for 21 days
. Isolation of hospitalized patients
. Passive immunization with ZIG, VZIG, or the intravenous formulation of ZIP. Both ZIG and VZIG should
be given within 96 hours (preferably within 72 hours) of exposure to ensure effi cacy. ZIP can be given
somewhat later. Recommended for persons exposed to chickenpox or shingles within 96 hours who are
immunocompromised, .15 years old without prior history of chickenpox, newborns of mothers with onset of chickenpox < 5 days before delivery or < 2 days after delivery. Exposure criteria: continued household
contact, prolonged face-to-face contact (same room), or indoor playmate > 1 hour.
. Varicella vaccine effectiveness decreases significantly after 1 year (most cases of breakthrough disease are
mild). If administered at younger than 15 months, the vaccines effectiveness was lower in the fi rst year after
vaccination, but the difference in effectiveness was not statistically signifi cant for subsequent years.
. Varicella-Virus vaccine (Varivax) - a live attenuated vaccine approved by the FDA and recommended by
ACIP for immunization of healthy individuals, 12 months and above, who have not had chickenpox
. 12m-12y: single dose 0.5 mL SC. Cumulative efficacy 70-90%.
. 13y and above: two 0.5 mL SC doses 4-8 weeks apart. Efficacy 70%.
. Has been shown to prevent or signifi cantly reduce the severity of varicella if given within 72 hours and
possibly up to 5 days, postexposure in several studies
. May be considered for a subset of HIV positive children in CDC Class I with CD4 > 25%
. Vaccine recipients should avoid contact with immunocompromised people, and pregnant women who have
never had chickenpox and their newborns, for up to 6 weeks after vaccination
POSSIBLE COMPLICATIONS:
. Secondary bacterial infection - cellulitis, abscess, erysipelas, sepsis, septic arthritis/osteomyelitis, staphylococcal pyomyositis
. Pneumonia (20-30% of adults with chickenpox have lung involvement)
. Encephalitis (the most common CNS complication)
. Reye syndrome
. Purpura
. Lymphadenitis
. Nephritis
EXPECTED COURSE/PROGNOSIS:
. In the healthy child, chickenpox is rarely a serious disease and recovery is complete
. Confers long immunity
. Second attack rare, but subclinical infection common
. Infection latent and may recur years later as herpes zoster in adults (and sometimes in children)
. Fatalities rarely occur from complications
AGE-RELATED FACTORS:
Pediatric:
β’ Neonates born to mothers who develop chickenpox 5 days before or 2 days after delivery are at risk for serious disease. Must give VZIG.
β’ Varicella bullosa seen mainly in children under two. Lesions appear as bullae instead of vesicles. Clinical
course unchanged. β’ Case-fatality (in USA) 2/100,000
β’ Most common cause of death: septic complications and encephalitis
Geriatric:
β’ Infection more severe than in children
β’ Latent varicella infection may reactivate and cause the exanthem shingles or zoster
β’ Case-fatality 30/100,000
β’ Most common cause of death: primary viral pneumonia