Can an 8-month-old infant contract chickenpox?

Chickenpox in 8-Month-Old Infants

Yes, an 8-month-old infant can contract chickenpox (varicella), as infants who have not been vaccinated and lack maternal antibodies are susceptible to the infection. 1

Susceptibility in Infants

• Chickenpox is a highly contagious disease caused by the varicella zoster virus (VZV) that can affect individuals of any age, including infants 2
• Before the varicella vaccine was available, approximately 4 million cases of chickenpox occurred annually in the United States, with 90% of cases occurring in children 2
• Infants under 12 months of age are not eligible for varicella vaccination, as the vaccine is only approved for children 12 months of age and older 2
• Infants may have some protection from maternal antibodies, particularly in the first few months of life, but this protection wanes over time 3

Disease Severity in Infants

• The severity of chickenpox varies by age, with disease progression typically being:
  • Mild in newborns (first month) due to maternal antibodies (only 10% develop complications) 3
  • Increasingly severe as age increases: 42% develop complications at 1-2 months, 66% at 3-5 months, 70% at 6-8 months, and 79% at 9-12 months 3
• Infants, along with adolescents, adults, and immunocompromised persons, are at higher risk for complications from chickenpox 2
• Among hospitalized children with chickenpox complications, approximately one-third are younger than 1 year of age 4

Clinical Presentation in Infants

• Chickenpox typically presents with fever, malaise, and a generalized vesicular rash consisting of 250-500 lesions 2
• In infants, common complications requiring hospitalization include:
  • Gastrointestinal disorders (30% of hospitalized cases) 4
  • Respiratory tract infections including pneumonia and bronchitis 4
  • Neurological complications (15% of hospitalized cases) 4
  • Bacterial skin infections 4

Management of Chickenpox in Infants

• For otherwise healthy 8-month-old infants with uncomplicated chickenpox, supportive care is the primary recommended treatment 1
• Supportive measures include:
  • Keeping the child comfortable and preventing scratching 1
  • Maintaining hydration and managing fever 1
• Antiviral therapy with acyclovir should be considered if the infant is immunocompromised or shows signs of severe disease 1
• The child should be isolated until all lesions have crusted over (typically 5-7 days) to prevent spread of the virus 1

Prevention

• Since varicella vaccine is not approved for children under 12 months of age, prevention relies on:
  • Avoiding exposure to individuals with active chickenpox or shingles 1
  • Ensuring household contacts are vaccinated (community immunity) 2
• Once the child reaches 12 months of age, varicella vaccination is recommended to prevent future infection 2
• For exposed susceptible infants, varicella-zoster immune globulin (VZIG) may be indicated for high-risk individuals 1

Important Considerations

• Chickenpox acquired in the first year of life increases the risk of developing herpes zoster (shingles) later in childhood 5
• Most cases of chickenpox in otherwise healthy infants resolve without complications within 5-7 days 1
• Hospitalization may be necessary for infants with severe disease or complications 3, 4

Remember that while chickenpox is often more severe in the first year of life compared to older children, the presence of maternal antibodies in the first few months can provide some protection, with disease severity typically increasing as these antibodies wane 3.