Varicella Vaccination and Post-Exposure Prophylaxis

Vaccination Guidelines

• The Centers for Disease Control and Prevention (CDC) recommends administering a second dose of varicella vaccine within 3-5 days of exposure, if the individual is at least 4 weeks past their first dose, with no subsequent work or school restrictions necessary after receiving the second dose 1
• For healthy, non-pregnant individuals 12 months of age or older, the CDC suggests administering the first dose of varicella vaccine within 3-5 days of exposure, with a second dose scheduled as age-appropriate, typically 3 months later for children during outbreaks, or per routine schedule 2
• Healthcare workers with one dose of vaccine should receive a second dose within 3-5 days of exposure, if at least 4 weeks have passed since the first dose, according to the CDC 1

Post-Exposure Prophylaxis

• Post-exposure vaccination is effective in preventing infection or reducing severity, with an effectiveness of over 90% within 3 days and approximately 70% within 5 days, as stated by the CDC 2
• Individuals receiving a second dose as post-exposure prophylaxis can return to school or work immediately, as recommended by the CDC 1, 2
• Patients without evidence of immunity to varicella should receive post-exposure prophylaxis with VariZIG as soon as possible (but within 10 days) after exposure to a person with varicella or shingles, as recommended by the CDC and supported by the Infectious Diseases Society of America (IDSA) 3, 4, 1, 5
• The recommended dose of VariZIG based on patient weight is as follows:

• Immunocompromised individuals, pregnant women, newborns, and premature infants without evidence of immunity should receive VariZIG, as recommended by the IDSA and the CDC 3, 4, 1, 6, 8
• For healthy, non-pregnant individuals ≥12 months of age without evidence of immunity, varicella vaccine can be administered within 3-5 days of exposure, with an effectiveness of 70-90% in preventing infection or reducing severity, as recommended by the Advisory Committee on Immunization Practices (ACIP) and the CDC 3, 4, 1, 6, 2
• When VariZIG is unavailable or administration window has passed, acyclovir prophylaxis may be considered, with a dosage of 20 mg/kg body weight (maximum 800 mg) per dose orally 4 times daily for 5-7 days, as suggested by the CDC and the American Academy of Pediatrics (AAP) 9, 2

Monitoring and Precautions

• Monitor closely for 28 days for development of varicella, and initiate antiviral treatment immediately if symptoms develop, as recommended by the AAP and the CDC 3, 4, 1, 6, 2
• VariZIG can extend the incubation period from 10-21 days to >28 days, and patients receiving VariZIG should be monitored closely for signs of varicella, as recommended by the IDSA and the CDC 3, 4, 6, 2
• Implement airborne and contact precautions for patients with varicella or disseminated herpes zoster, and only healthcare personnel with evidence of immunity should care for patients with confirmed or suspected VZV infection, maintaining precautions until all lesions are dry and crusted, as recommended by the CDC 1
• Patients with varicella or herpes zoster should cover all lesions with clean, dry bandages or clothing until they are completely dry, and susceptible individuals should avoid direct contact with lesions, as recommended by the CDC 10

Special Considerations

• Healthcare workers exposed to shingles should be monitored daily during days 8-21 post-exposure, and those with 1 dose of vaccine should receive a second dose within 3-5 days (if ≥4 weeks since first dose), as recommended by the CDC and the Occupational Safety and Health Administration (OSHA) 3, 4, 1
• Unvaccinated healthcare workers without immunity should be furloughed during days 8-21 post-exposure and vaccinated, as recommended by the CDC and OSHA 3, 4, 1
• VariZIG is generally well-tolerated, with the most common adverse reactions being pain at injection site (2%) and headache (2%), as reported by the CDC 6
• Contraindications include history of anaphylactic or severe systemic reactions to human immune globulins and IgA-deficient patients with antibodies against IgA and history of hypersensitivity, as stated by the CDC 6