varicella-zoster%20virus%20infection
VARICELLA-ZOSTER VIRUS INFECTION
Varicella, also known as chickenpox, is a self-limited benign disease caused by primary varicella-zoster virus (VZV) infection characterized by fever, malaise, and generalized pruritic vesicular rash.
The average incubation period is 14-16 days. It is transmitted via direct contact with vesicular fluid or inhalation of aerosolized respiratory secretions or via droplet route during face-to-face contact.
Hallmark sign is pruritic rash that begins in the scalp and face which eventually spreads to the trunks and extremities.

Prevention

  • 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 that VZV vaccine
  • Several studies have shown that this vaccine can reduce the incidence of herpes zoster, the burden of illness, and the incidence of post-herpetic neuralgia (PHN)
  • Recommended for patients aged >60 years old
  • Should not be used in the presence of acute febrile illness, active untreated tuberculosis, or pregnancy

Varicella Zoster Virus Vaccine

  • 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 with CD4 counts ≥200 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 postherpetic neuralgia (PHN)
  • Contraindicated in immunocompromised or pregnant patients & 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
    • 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
    • <28 weeks age of gestation (AOG)-born hospitalized premature infants regardless if the mother is with or without VZV infection
    • 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 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

Further Evaluation

  • 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
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Infectious Diseases - Malaysia digital copy today!
DOWNLOAD
Editor's Recommendations
Most Read Articles
09 Oct 2017
Pleural fluid lactic dehydrogenase (LDH) and glucose are useful parameters for evaluating severity of paediatric community acquired complicated pneumonia (PCACP), according to a study. Measurements of both parameters strongly correlate with prolonged hospitalization as an indirect indicator of disease severity.
5 days ago
Use of systemic antibiotics, in conjunction with performance of incision and drainage, in the management of paediatric acute skin and soft tissue infection (SSTI) appears to reduce Staphylococcus aureus colonization and the likelihood of infection recurrence, a prospective study has found.
6 days ago
Retreatment with ledipasvir and sofosbuvir with add-on ribavirin appears to be effective and well tolerated in genotype 1 hepatitis C virus (HCV)-infected patients who have failed to respond to daclatasvir/asunaprevir combination therapy, according to a study.
Elaine Tan, 14 Aug 2017

Complicated and uncomplicated urinary tract infections (UTIs) in adults and children should be managed by identifying and treating predisposing or underlying risk factors, with antimicrobial treatment, if needed, based on urine culture results and regional antibiotic resistance patterns, according to new guidelines of the Urological Association of Asia (UAA) and Asian Association of UTI and STD (AAUS).