Varicella Prevention and Treatment Recommendations
The recommended method for varicella prevention is a two-dose vaccination schedule for all susceptible individuals, with the first dose at 12-15 months and second dose at 4-6 years of age for children, and two doses 4-8 weeks apart for individuals ≥13 years without evidence of immunity. 1, 2
Vaccination Recommendations
Children (12 months to 12 years)
- Routine two-dose vaccination schedule is recommended with:
- The minimum interval between doses is 3 months, but if the second dose was administered ≥28 days after the first dose, it is considered valid 1
- MMRV (measles-mumps-rubella-varicella) combination vaccine may be used when all components are indicated 1
Adolescents and Adults (≥13 years)
- Two doses of single-antigen varicella vaccine administered 4-8 weeks apart for those without evidence of immunity 1, 2
- If >8 weeks elapse between doses, the second dose should still be administered without restarting the schedule 1
High-Risk Groups Requiring Special Consideration
- Healthcare personnel without evidence of immunity 1, 2
- Household contacts of immunocompromised persons 2
- Persons who live or work in environments where transmission is likely (teachers, daycare employees, institutional residents and staff) 1
- College students, inmates and staff of correctional institutions, and military personnel 1
- Nonpregnant women of childbearing age 1
- International travelers 1
Post-Exposure Prophylaxis
- Varicella vaccine is effective when administered within 3 days, and possibly up to 5 days, after exposure to prevent or modify disease severity 1, 2
- For susceptible exposed persons with contraindications to vaccination, VariZIG should be administered as soon as possible, ideally within 96 hours of exposure 2
Treatment of Active Varicella Infection
- For children with chickenpox (2 years and older): Acyclovir 20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days 3
- For adults and children over 40 kg with chickenpox: Acyclovir 800 mg 4 times daily for 5 days 3
- Treatment should be initiated at the earliest sign or symptom of chickenpox; efficacy is not established if started >24 hours after onset 3
- For immunocompromised patients with varicella-zoster infections, intravenous acyclovir is indicated 3, 4
- Valacyclovir is indicated for treatment of chickenpox in immunocompetent pediatric patients aged 2 to <18 years, initiated within 24 hours after rash onset 5
Evidence of Immunity to Varicella
Evidence of immunity to varicella includes any of the following 1, 2:
- Documentation of age-appropriate vaccination
- Laboratory evidence of immunity or laboratory confirmation of disease
- Birth in the United States before 1980 (not valid for healthcare workers)
- Physician diagnosis or verification of a history of varicella disease
- History of herpes zoster verified by a healthcare provider
Implementation Strategies
- All states should require children entering child care facilities and elementary schools to have received varicella vaccine or have other evidence of immunity 1
- School and college entry requirements should be established at all grade levels 2
- Healthcare institutions should assess immunity status of all personnel and vaccinate those without evidence of immunity 2
Effectiveness and Impact of Vaccination
- Two-dose vaccination is significantly more effective than a single dose, with vaccine efficacy of 98% for two doses compared to 94% for one dose over a 10-year observation period 6
- Recipients of two doses are 3.3-fold less likely to develop breakthrough varicella compared to those who receive one dose 7, 6
- High vaccination coverage (>88%) has resulted in 71-84% decrease in reported varicella cases, 88% decrease in hospitalizations, 59% decrease in ambulatory care visits, and 92% decrease in varicella-related deaths in young children 1