What are the recommendations for varicella (chickenpox) prophylaxis?

Varicella Prophylaxis Recommendations

Varicella prophylaxis should include vaccination of all susceptible individuals without evidence of immunity, with post-exposure vaccination within 3-5 days of exposure and VariZIG administration for high-risk individuals with contraindications to vaccination. 1

Vaccination Recommendations by Age Group

Children 12 months to 12 years

• Routine two-dose vaccination schedule with the first dose at 12-15 months and second dose at 4-6 years 1
• For children who previously received only one dose, a catch-up second dose is recommended with a minimum interval of 3 months between doses 1
• MMRV (ProQuad®) or single-antigen varicella vaccine (VARIVAX®) may be used for children in this age group 1

Persons 13 years and older

• Two doses of single-antigen varicella vaccine administered 4-8 weeks apart for those without evidence of immunity 1
• Only single-antigen varicella vaccine should be used (MMRV is not licensed for use in persons >13 years) 1

Priority Groups for Vaccination

Susceptible individuals at high risk for exposure or transmission should receive special consideration for vaccination:

• Healthcare personnel 1
• Household contacts of immunocompromised persons 1
• Teachers, daycare employees, and staff in institutional settings 1
• College students, inmates and staff of correctional institutions, and military personnel 1
• Nonpregnant women of childbearing age 1
• Adolescents and adults living in households with children 1
• International travelers 1

Post-Exposure Prophylaxis

Vaccination as Post-Exposure Prophylaxis

• Varicella vaccine is effective when administered within 3 days of exposure, and possibly up to 5 days post-exposure 1
• Vaccine effectiveness is approximately 70-90% in preventing varicella when given post-exposure 1, 2, 3
• For persons who have received one dose previously, a second dose can be administered post-exposure 1, 2
• Post-exposure vaccination is most effective when administered within 3 days of exposure (77% effectiveness) compared to >3 days (64% effectiveness) 2

VariZIG for High-Risk Individuals

• VariZIG (Varicella-Zoster Immune Globulin) should be administered to susceptible persons at high risk for severe disease and complications who have contraindications for vaccination 1
• VariZIG provides maximum benefit when administered as soon as possible after exposure, but may be effective if given within 96 hours of exposure 1
• Candidates for VariZIG include:
  • Immunocompromised patients 1
  • Pregnant women without evidence of immunity 1
  • Newborns of mothers with varicella onset within 5 days before or 2 days after delivery 1
  • Premature infants 1
  • Infants <1 year of age 1

Evidence of Immunity to Varicella

Evidence of immunity to varicella includes any of the following:

• Documentation of age-appropriate vaccination 1
• Laboratory evidence of immunity or laboratory confirmation of disease 1
• Birth in the U.S. before 1980 (except for healthcare workers, pregnant women, and immunocompromised persons) 1
• Diagnosis or verification of a history of varicella disease by a healthcare provider 1
• Diagnosis or verification of a history of herpes zoster by a healthcare provider 1

Special Considerations

Pregnant Women

• Prenatal assessment of women for evidence of varicella immunity is recommended 1
• Birth before 1980 is not considered evidence of immunity for pregnant women 1
• Vaccination should be deferred during pregnancy 1
• Women without evidence of immunity should receive the first dose of vaccine before discharge after delivery and the second dose 4-8 weeks later 1

HIV-Infected Individuals

• Vaccination may be considered for HIV-infected children with age-specific CD4+ T-lymphocyte percentages of 15-24% 1
• Vaccination may be considered for HIV-infected adolescents and adults with CD4+ T-lymphocyte counts >200 cells/μL 1

Implementation Strategies

• School and college entry requirements should be established to ensure students at all grade levels are protected against varicella 1
• Healthcare institutions should assess immunity status of all personnel and vaccinate those without evidence of immunity 1
• Catch-up vaccination can be implemented during routine healthcare visits 1
• For outbreak control, state and local health departments should consider offering vaccination to exposed susceptible individuals 1

Common Pitfalls and Caveats

• Do not administer MMRV to persons aged >13 years 1
• Do not restart the vaccination schedule if >8 weeks elapse after the first dose; simply administer the second dose 1
• Do not consider birth before 1980 as evidence of immunity for healthcare workers, pregnant women, or immunocompromised persons 1
• VariZIG effectiveness decreases significantly when administered >96 hours after exposure 1
• Vaccine effectiveness as post-exposure prophylaxis decreases when administered >3 days after exposure 2