What is the appropriate site for administering the varicella vaccine in a 15‑month‑old child?

Varicella Vaccine Administration Site in a 15-Month-Old Child

The varicella vaccine should be administered subcutaneously in the anterolateral thigh or deltoid region in a 15-month-old child. 1

Recommended Route and Site

• The FDA-approved route for varicella vaccine (VARIVAX) is subcutaneous or intramuscular administration, with subcutaneous being the standard recommended route. 1

• For children aged 12-15 months, the preferred injection sites are:

  • Anterolateral thigh (most common site for this age group) 1
  • Deltoid muscle (acceptable alternative) 1

• The anterolateral thigh is typically preferred in younger toddlers (12-15 months) because it provides adequate subcutaneous tissue and muscle mass for safe vaccine administration. 1

Dose and Volume Specifications

• Each dose of varicella vaccine is 0.5 mL administered subcutaneously. 1, 2

• The vaccine should be injected into the subcutaneous tissue, which lies between the dermis and muscle layer. 1

Evidence Supporting Subcutaneous Administration

• While the FDA label specifies that varicella vaccine may be given either subcutaneously or intramuscularly, subcutaneous administration is the recommended standard route. 1

• A comparative study demonstrated that both subcutaneous and intramuscular routes produce excellent immunogenicity, with 97% seroconversion via subcutaneous route versus 100% via intramuscular route—a difference that is not clinically significant. 3

• Inadvertent intramuscular administration does not require revaccination, as immunogenicity remains excellent by either route. 3

Practical Administration Technique

• Use a 5/8-inch to 3/4-inch needle at a 45-degree angle for subcutaneous injection in the anterolateral thigh of a 15-month-old child. 1

• Pinch the subcutaneous tissue to ensure the needle enters the subcutaneous space rather than muscle. 1

• The vaccine must be administered immediately after reconstitution and discarded if not used within 30 minutes. 1

Common Pitfalls to Avoid

• Do not administer intradermally—this is not an approved route and may result in inadequate immune response. 1

• Do not use preservatives, antiseptics, or detergents when reconstituting or administering the vaccine, as these substances may inactivate the live attenuated virus. 1

• Do not combine varicella vaccine with any other vaccine through reconstitution or mixing in the same syringe. 1

• Ensure the child has no contraindications before administration, including severe immunodeficiency, pregnancy (not applicable at this age), or history of anaphylactic reaction to vaccine components such as neomycin or gelatin. 2

Vaccination Schedule Context

• This 15-month-old child is receiving the first dose of varicella vaccine, which is routinely recommended at 12-15 months of age. 2, 1

• The second dose should be administered at 4-6 years of age, with a minimum interval of 3 months between doses. 2, 1

• At least 99% of children achieve protective antibody levels after completing the two-dose series, compared to only 76-85% after a single dose. 4, 2