What is the recommended management for varicella (chickenpox) in children?

Management of Varicella (Chickenpox) in Children

Primary Prevention: Two-Dose Vaccination Strategy

All children should receive two doses of varicella vaccine: the first dose at 12-15 months of age and the second dose at 4-6 years of age (before kindergarten entry), as this provides 98% efficacy against any varicella disease and 100% efficacy against severe disease. 1

Vaccination Schedule

• Children 12 months through 12 years: Two 0.5-mL doses administered subcutaneously, separated by at least 3 months 1
• If the second dose is inadvertently given between 28 days and 3 months after the first dose, it does not need to be repeated 1
• Adolescents ≥13 years: Two 0.5-mL doses separated by at least 28 days 1

Available Vaccines

• Monovalent varicella vaccine (Varivax): approved for children ≥12 months 1
• Quadrivalent MMRV vaccine (ProQuad): approved only for children 12 months through 12 years 1
• Combination vaccines are preferred when all components are indicated to minimize injections 1

Post-Exposure Prophylaxis

For susceptible children exposed to varicella, administer varicella vaccine within 3 days of exposure for >90% effectiveness in preventing disease, or within 5 days for 70% effectiveness in preventing disease and 100% effectiveness in modifying severe disease. 2

Household Exposure Management

• Household contacts have the highest risk of infection, with approximately 85% (range 65-100%) of susceptible contacts developing varicella 2
• Both susceptible household contacts should receive immediate vaccination if they lack immunity 2, 3
• No contraindications exist for vaccinating healthy children after household exposure 2

High-Risk Exposures Requiring VZIG (Not Routine Vaccination)

• Immunocompromised patients 2
• Neonates with specific maternal exposure timing 2
• Premature infants 2
• Note: VZIG is NOT indicated for otherwise healthy children 2

Treatment of Active Varicella Infection

Supportive Care (Primary Management for Healthy Children)

For otherwise healthy children with uncomplicated varicella, supportive care is the primary treatment, as oral acyclovir is not routinely recommended due to marginal therapeutic benefit. 3, 4

Symptomatic Management

• Relieve itching with lukewarm baths containing colloidal oatmeal 3
• Avoid salicylates (aspirin) for 6 weeks after varicella due to Reye syndrome risk 2
• Most cases resolve without complications within 5-7 days 3

Isolation Requirements

• Keep child isolated until all lesions have crusted over (typically 5-7 days) 3
• Infected hosts are contagious from 1-2 days before rash onset until all lesions are crusted 1

Antiviral Therapy: When to Consider Acyclovir

Oral acyclovir should be considered for specific high-risk groups if initiated within 24 hours of rash onset, but is NOT routinely recommended for otherwise healthy children. 4

Indications for Acyclovir Treatment

• Otherwise healthy individuals ≥13 years of age 4
• Children >12 months with chronic cutaneous or pulmonary disorders 4
• Children receiving long-term salicylate therapy 4
• Immunocompromised children (requires IV acyclovir, not oral) 3, 5

Acyclovir Dosing (FDA-Approved)

• Children ≥2 years and ≤40 kg: 20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days 6
• Children >40 kg and adults: 800 mg orally 4 times daily for 5 days 6
• Immunocompromised patients: IV acyclovir is indicated 6

Evidence Limitations for Routine Acyclovir Use

• Oral acyclovir typically results in only a 1-day reduction in fever and 15-30% reduction in symptom severity 4
• Has not been shown to reduce acute complications, pruritus, spread of infection, or duration of school absence 4
• Therapy initiated >24 hours after illness onset loses therapeutic effect 4
• The certainty of evidence for reducing complications is very low 7

Recognition and Management of Complications

Most Common Complications Requiring Immediate Recognition

Secondary bacterial skin infections (44% of hospitalized cases), CNS involvement (23%), and pneumonia (18%) are the most critical complications, with bacterial superinfections primarily caused by Staphylococcus aureus and Streptococcus pyogenes. 8

Bacterial Superinfections (Most Common)

• Account for 44% of varicella-related hospitalizations 8
• Primary pathogens: S. aureus (75% of positive cultures) and S. pyogenes (25%) 8
• Treatment: Early surgical intervention for invasive infections; appropriate antibiotics based on culture 2

CNS Complications

• Account for 23% of hospitalizations 8
• Age >8 years is significantly associated with CNS complications (p=0.019) 8
• Leading cause of varicella-related deaths along with pneumonia 2

Pneumonia

• Accounts for 18% of hospitalizations 8
• Leading cause of varicella-related mortality 2

High-Risk Populations

• Infants <1 year: 6 times more likely to be hospitalized than children aged 5-9 years 2
• Immunocompromised children: Require IV acyclovir; oral acyclovir prevents dissemination when given early 5

Mortality Considerations

• Case-fatality rate: approximately 2.2% in hospitalized children 8
• Deaths primarily from pneumonia, CNS complications, and invasive bacterial infections (S. aureus septicemia, streptococcal toxic shock syndrome) 8
• Mortality is rare in immunocompetent children 2

Evidence of Immunity (Who Does NOT Need Vaccination)

Children with documented history of varicella disease verified by a healthcare professional do not require vaccination, as prior infection provides natural immunity. 9

Acceptable Documentation of Immunity

1. Documentation of 2 appropriately timed vaccine doses 1
2. Laboratory evidence of immunity or laboratory-confirmed disease 1
3. Varicella diagnosed by a healthcare professional or verified history 1
4. History of herpes zoster diagnosed by a healthcare professional 1

Verification Requirements

• For typical disease: any healthcare professional can verify (nurse, NP, PA, physician) 1
• For atypical/mild cases: physician assessment recommended with either epidemiologic link to confirmed case OR laboratory confirmation 1

Special Populations and Contraindications

Immunocompromised Children

• Do NOT routinely vaccinate children with congenital or acquired T-lymphocyte immunodeficiency, leukemia, lymphoma, or those receiving long-term immunosuppressive therapy 1
• Exception: certain HIV-infected children may be vaccinated with expert guidance 1
• If vaccine-related varicella develops in high-risk patients, treat with acyclovir (Oka vaccine strain remains acyclovir-susceptible) 1

Pregnancy-Related Considerations

• Prenatal screening for VZV immunity is recommended for pregnant adolescents 1
• Varicella vaccine should NOT be administered to pregnant women 1
• Postpartum women without immunity should receive monovalent vaccine before hospital discharge, with second dose ≥28 days later 1
• Counsel women to avoid conception for 1 month after each vaccine dose 1
• Pregnant household members are NOT a contraindication for vaccinating other children in the household 1
• Nursing mothers without immunity should receive monovalent varicella vaccine 1

Key Clinical Pitfalls to Avoid

• Do not delay post-exposure vaccination: Efficacy drops significantly after 3 days, though some benefit remains up to 5 days 2
• Do not prescribe oral acyclovir for healthy children with uncomplicated varicella: Marginal benefit does not justify routine use 4
• Do not start acyclovir >24 hours after rash onset in otherwise healthy patients: Therapeutic effect is lost 4
• Do not use aspirin or salicylates: Risk of Reye syndrome 2
• Do not assume mild atypical rashes were varicella without proper verification: Other diseases can mimic mild varicella 1
• Do not withhold vaccination from household contacts of immunocompromised individuals: Family immunodeficiency is not a contraindication for vaccinating healthy siblings 1