Can a 3-Month-Old Catch Shingles?
A 3-month-old infant cannot "catch" shingles from someone else, but can develop shingles if they were exposed to varicella-zoster virus (VZV) in utero during pregnancy. 1
Understanding the Distinction
What Infants Can Catch from Exposure
- A 3-month-old exposed to someone with shingles can develop chickenpox (varicella), not shingles. 2, 3
- Shingles is caused by reactivation of latent VZV that already exists in the body's nerve ganglia—it is not a primary infection that can be transmitted directly. 1, 4
- The virus can be transmitted from shingles lesions to susceptible contacts, but this results in chickenpox, not shingles. 1
- The risk of VZV transmission from someone with shingles is approximately 20% of the risk from someone with active chickenpox. 1
How Infants Can Develop Shingles
Infants can develop shingles only if they had prior VZV infection, which occurs through:
- In utero exposure during pregnancy: When mothers have varicella during pregnancy (particularly at 13-36 weeks gestation), the virus can cross the placenta and establish latent infection in the fetus. 1
- The prospective data shows herpes zoster occurred in 0.8% of infants exposed to VZV at 13-24 weeks' gestation and 1.7% of those exposed at 25-36 weeks' gestation. 1
- Neonatal varicella: Infants born to mothers who develop varicella from 5 days before to 2 days after delivery can develop severe neonatal varicella, which can later reactivate as shingles. 1
Risk Factors for Infant Shingles
Initial infection with varicella in utero or during early childhood (age <18 months) is a recognized risk factor for developing herpes zoster. 1
- This occurs because the immature immune system may not adequately control viral latency. 1
- Immunosuppression also increases risk for shingles at any age. 1
Clinical Implications
If Exposure to Shingles Occurs
- The infant is at risk for developing chickenpox, not shingles. 1, 2
- Varicella-zoster immune globulin (VZIG) should be considered for high-risk exposed infants without immunity within 96 hours of exposure. 1, 5
- Infants under 12 months cannot receive varicella vaccine, so passive immunization with VZIG is the only preventive option for susceptible exposed infants. 1
If Infant Develops Chickenpox
- Supportive care is the primary treatment for otherwise healthy infants with uncomplicated varicella. 5
- Antiviral therapy with acyclovir should be considered if the infant is immunocompromised or receiving immunosuppressive therapy. 5
- Isolation until all lesions have crusted over (typically 5-7 days) is recommended. 5
Important Caveats
- Maternal shingles during pregnancy does not cause congenital varicella syndrome—no cases occurred among 366 infants whose mothers had herpes zoster during pregnancy. 1
- This is in stark contrast to maternal chickenpox during pregnancy, which carries significant fetal risk. 1
- The distinction between chickenpox and shingles exposure is critical for counseling families about transmission risk and expected outcomes. 1, 2