Varicella Management

• Avoidance of varicella is the only guaranteed method of preventing complications
  
  • Patients infected with varicella-zoster virus (VZV) are contagious for 24-48 hours prior to the emergence of clinical signs until 5-6 days after onset of rash, during which vesicles have evolved into dried crusts

Active Prophylaxis

Herpes Zoster Vaccine

• A high-dose live-attenuated vaccine of the Oka strain; 14 times more potent than VZV vaccine
• Several studies have shown that this vaccine can reduce the incidence of herpes zoster, the burden of illness, and the incidence of postherpetic neuralgia (PHN)
• The recombinant adjuvanted zoster vaccine is recommended for patients aged ≥50 years old
• Should not be used in the presence of acute febrile illness, active untreated tuberculosis, or pregnancy

Varicella-Zoster Virus Vaccine (Varicella-Zoster Virus, Live Attenuated)

• Live attenuated vaccine of the Oka strain that provides long-lasting resistance against varicella
  
  • The vaccine strain causes subclinical VZV infection in vaccinees and leads to immunity
  • As a live herpes virus, it may establish latency and reactivate later on
• May be given to immunocompetent individuals >12 months of age who do not have a history of VZV infection
  • 1st dose is given at age 12-15 months and 2nd dose at age 4-6 years
  • Non-immunized adults and adolescents >12 years are recommended to have 2 doses given 4-8 weeks apart
  • Children >12 months infected with human immunodeficiency virus (HIV) with age-specific CD4+ T-lymphocyte percentages of ≥15% should receive 2 doses given 3 months apart
  • HIV-infected individuals >8 years old with CD4 counts of ≥200 cells/microL should also receive 2 doses given 3 months apart
• A high-titer VZV vaccine can be given to adults ≥50 years old which will decrease incidence of herpes zoster infection, disease burden, and PHN
• Contraindicated in immunocompromised or pregnant patients and infants <12 months

Passive Prophylaxis

Varicella-Zoster Virus Immunoglobulin G (VZV IgG/VZIG)

• A high-titer preparation of VZV IgG antibodies
  
  • Improves symptoms of chickenpox in high-risk individuals
• May be given to susceptible high-risk individuals including immunocompromised children without a history of VZV infection and pregnant women without history of VZV and no antibody to VZV who have had a close exposure to an individual with varicella or herpes zoster
  • <28 weeks age of gestation (AOG)-born hospitalized premature infants regardless if the mother is with or without VZV infection 
  • May also be considered in newborn infants born to mothers with signs and symptoms of infection within 5 days before to 2 days after delivery
  • May also be considered in premature infants born at ≥28 weeks of gestation with postnatal exposure and whose mothers have no evidence of immunity
  • Individuals with contraindications to vaccine and who lack evidence of immunity to varicella, whose exposure is likely to result in infection, and are at high risk for severe varicella
• Not generally recommended in healthy susceptible adults since these patients can be given oral antivirals if varicella infection develops
• Administer within 10 days post-exposure; ideally within 96 hours (4 days) post-exposure
• Effects: Patients may still develop varicella despite VZIG but the risk of varicella pneumonia is significantly reduced if passive prophylaxis is used

Post-exposure Prophylaxis

Varicella-Zoster Virus Vaccine (Varicella-Zoster Virus, Live Attenuated)

• Varicella vaccine is recommended in susceptible individuals after exposure to varicella
• Varicella vaccine is effective in preventing illness or modifying varicella severity if given within 3 days and potentially up to 5 days after exposure
• If the exposure did result in infection, the administration of varicella vaccine during prodromal stage does not appear to increase the risk for vaccine-related adverse effects
• Contraindicated in immunocompromised or pregnant patients

Breakthrough Varicella

• A wild-type VZV that occurs >42 days post-vaccination against varicella
  • More common in individuals given 1 dose than those who have received 2 doses
• Persons with breakthrough varicella remain contagious until no new lesions have appeared within 1 day
• Symptoms are usually mild, presenting with low fever and significantly lesser (<50) skin lesions
  • Rashes are predominantly maculopapular and rarely progresses to vesicular lesions

• Further evaluation is needed especially in immunocompromised patients
• Observe for the following in varicella-zoster virus (VZV) infection:
  
  • Other bacterial, neurologic, respiratory, hepatic, hematologic complications
  • Appearance of rash in dermatomal distribution that is predictive of herpes zoster which usually follows latent period of many years
• Observe for the following in herpes zoster:
  • Other bacterial, neurologic, ophthalmic, respiratory, hepatic, hematologic complications
  • Persistent pain after 1-3 months of rash resolution is suggestive of postherpetic neuralgia