Is it okay if a 15-month-old infant barely received any vaccine due to movement during administration?

Incomplete Vaccine Administration Due to Infant Movement

If a substantial amount of vaccine was not delivered due to infant movement during injection, the dose should be repeated immediately at the same visit, or if discovered later, a full dose should be administered as soon as the child can return. 1

Immediate Action Required

The Advisory Committee on Immunization Practices (ACIP) provides clear guidance for this exact scenario:

• If the error is discovered while the child is still present, administer the remaining volume needed to complete a full dose during the same visit. 1
• If measuring the exact remaining volume is challenging, administering a complete repeat dose at full volume is acceptable and preferred. 1
• If the error is discovered after the child has left, a full dose should be administered as soon as the recipient can return to the clinic. 1

Why This Dose Must Be Repeated

ACIP strongly discourages any variations from recommended vaccine dosing:

• Administering volumes smaller than recommended can result in inadequate protection against vaccine-preventable diseases. 1
• Any vaccination using less than the standard dose should not be counted as a valid dose in the child's immunization record. 1
• The child should be revaccinated according to age-appropriate schedules, treating this as if the dose was never given. 1

Safety of Repeating the Dose

There is minimal risk associated with repeating a vaccine dose that may have been partially administered:

• Studies of inadvertent vaccine administration errors in children show that adverse reactions are rare and, when they occur, are non-serious and resolve without sequelae. 2
• The primary concern with vaccine errors is inadequate protection from disease, not safety from re-administration. 1

Documentation and Follow-Up

• Do not count the incomplete dose in the child's vaccination record. 1
• Document the incident and the corrective action taken (repeat dose administered). 1
• Ensure the repeat dose is given with proper technique to avoid recurrence—consider having an assistant gently stabilize the injection site. 1

Common Pitfall to Avoid

Do not assume "some vaccine got in" is sufficient. The ACIP explicitly states that split doses or reduced volumes have not been adequately studied for serologic response or clinical efficacy, and such practices are not endorsed. 1 When in doubt about whether a full dose was delivered, always err on the side of re-administering the complete dose to ensure adequate protection.