Chickenpox in Children, Adults and Pregnancy: What to do?

•Dr. Nayyar Raza Kazmi

•Community Pediatrics Project

•Department of Health, Government of NWFP

BACKGROUND• > 90% of population infected by 15 yrs

• attack rates 90% for household contacts

• morbidity

– bacterial skin infections

– pneumonia

– encephalitis, post varicella cerebritis

– days from school/work

– hospitalizations (<1%)

BACKGROUND

• risk of death:– lower for children than infants

– increases with age for adolescents/adults• 30% for perinatally exposed infants• 2/100,000 aged 1-14• 2.7/100,000 aged 15-19• 25.2/100,000 aged 30-49

STRATEGIES

Prevent infection?– infection control

– passive vaccination (VZIG)

– active vaccination (live attenuated)

Treat infection?– who to treat?

– what to treat with?

VARICELLA IN CHILDREN

Prevention Options

-vaccination

-school omission

Treatment Options

-symptomatic

-antiviral medications

VARICELLA VACCINE: Efficacy

• 96-100% seroconversion within 4-6 weeks post vaccination

• > 90% with high titers after 20 years

• < 2% breakthrough of varicella 2 years out– attenuated disease

• Not available in Pakistan

VARICELLA VACCINE:Side Effects

• fever (12%)

• pain at site (2%)

• rash at injection site (1.5%)

• generalized rash (1.5%)

• transmission of vaccine virus– higher if vaccinees are immunocompromised

WHO SHOULD BE VACCINATED?

YES• > 1 year of age• varicella susceptible

– no history of chicken pox

• no contraindications

NO• < 1 year of age• immunedeficient in

household• pregnancy• mild natural

chickenpox

VARICELLA IN CHILDREN

Usually previously well children develop malaise and low grade fever which rises once the rash appears. The rash begins along the hairline on face as macules which progresses to tiny vesicles with surrounding erythema.(Dew drops on rose petal appearance) . Rash then appears in successive crops over the trunk and extremities. They heal in 7-10 days. Sometimes hemorrhage may occur within the vesicles which may be mistaken as Meningococcemia.

SCHOOL WITHDRAWALSThe Evidence

• contagious 1-2 days before the rash until all lesions crusted

• documented transmission of infection to classmates prior to rash (AJDC 1989-Brunell)

* RCT Randomized Control Trial

ACYCLOVIR IN CHILDRENThe Evidence

Balfour et al J Peds 1990 & Dunkle et al NEJM 1991

• RCT of 102 and 815 children

• acyclovir (20mg/kg/dose) qid vs placebo

lesions, fever, itching

• no change in complications or titers

ACYCLOVIR IN CHILDREN

• no serious adverse drug reactions noted

• cost of medications needs to be considered!!!!

** acyclovir is not routinely recommended for the treatment of chickenpox in healthy children

PROPHYLACTIC ACYCLOVIR IN CHILDREN

• 40 mg/kg/day after exposure symptomatic cases with acyclovir vs

placebo (16% vs 100%) (Asano et al Pediatrics 1993)

• 79-85% still had serologic evidence of infection

PROPHYLACTIC ACYCLOVIR IN CHILDREN

severity if acyclovir given for two weeks (Suga et al Arch Dis Child 1993, PIDJ 1998)

• development of resistance is a concern

**routine acyclovir prophylaxis not recommended in otherwise healthy children

VARICELLA IN HEALTHY ADULTS

38 yo healthy man with no previously documented chicken pox develops fever and vesicular rash 18 days after his son recovers from chickenpox.

Has lesions in mouth and urethra and increasing cough.

VARICELLA IN HEALTHY ADULTS

incidence of pneumoniahospitalization rates (10%)mortality compared to childrentime from work/school

VARICELLA IN ADULTSThe Evidence

• RCT’s in adults with acyclovir given within 24 hours of onset– 800mg qid x 5 days duration, severity of illness (Wallace et al An n Int Med; 1992, Feder Arch Intern Med;1990)

• No studies to date with valacyclovir or famciclovir

VARICELLA IN PREGNANCY

• pregnancy alters cellular immunity needed to fight viral infections

pneumonitis mortalitymaternal complications in 2nd and 3rd

trimester– premature labour/delivery, IUGR

• small risk of fetal infection

VARICELLA IN PREGNANCY-What To Do?

• prevent infection– VZIG

– infection control

• diagnose early

• treat infection

VARICELLA IN PREGNANCY-The Evidence

• no evidence to suggest that maternal acyclovir prevents fetal infection

• no evidence of teratogenic effect of acyclovir at therapeutic doses

• high doses have in vitro effects

VARICELLA IN PREGNANCY

• treat based on maternal status 800mg qid x 5 days IV therapy if pneumonia

VARICELLA IN FETUS

• 2.2% transmission to fetus (1.2%-4.9%) (Pastuszak et al NEJM 1994)

• intrauterine infection more common in 1st trimester

• congenital infection– scarring, limb deformities, cataracts,

CNS involvement, chorioretinitis

• neonatal or childhood zoster (0.8% -1%)

VARICELLA IN NEONATES

• during maternal varicella 24% of fetuses get transplacentally infected

• critical times – is 5 days before to 2 days after birth– neonates < 28 weeks gestation or <1000gm– 1st month of life if mother non-immune and in

NICU, immunedeficiency etc

• infant mortality up to 30%

VARICELLA IN NEONATES

Infant born at full term following uncomplicated delivery. Mother noticed to have varicella lesions 2 days prior to delivery with low grade fever.

Infant is completely well with no skin lesions, no fever etc.

VARICELLA IN NEONATES The Evidence

• VZIG if peripartum maternal infection (Hanngren K et al Scand J Infect Dis 1985)

• attack rate still 51%

• incubation period of 11 days• attenuates infection (Miller et al. Lancet 1989 )

mortality rate (1-2%), lesions

• no literature regarding the use of acyclovir for prevention of disease in this group

VARICELLA IN NEONATES

Perinatal Exposure– treat with acyclovir due to high mortality

< 4 weeks of age– treat if mother is not immune, if infant

born < 28 weeks gestation, < 1000gm, sick in NICU

• no clinical trials to date however good studies with acyclovir in other neonatal infections