Will administering a third dose of varicella (chickenpox) vaccine within 21 days of the second booster dose, given 5 years after the initial dose at 1 year of age, cause any issues?

From the Guidelines

Giving a third dose of varicella vaccine within 21 days after the second dose is unnecessary and not recommended. The standard varicella vaccination schedule consists of two doses: the first at 12-15 months of age and the second between 4-6 years of age, as recommended by the Advisory Committee on Immunization Practices (ACIP) 1. Once these two doses are completed, no additional boosters are currently recommended for routine immunization. The third dose given so soon after the second dose would not provide additional immunity because the immune system needs time to respond fully to the previous dose.

Key Points to Consider

• The two-dose series provides long-lasting immunity against chickenpox for most individuals, with the vaccine being approximately 85% effective in preventing varicella and >95% effective in preventing severe varicella disease 1.
• While this extra dose is unlikely to cause harm beyond possible local injection site reactions, it offers no clinical benefit and represents an unnecessary medical intervention.
• If the third dose was already administered, no corrective action is needed, but future doses should follow standard recommendations.
• For special populations like immunocompromised individuals, different schedules may apply, and a healthcare provider should be consulted for personalized guidance.

Evidence-Based Recommendations

The American Academy of Pediatrics recommends that children 12 months through 12 years of age should receive two 0.5-mL doses of varicella vaccine administered subcutaneously, separated by at least 3 months 1. This recommendation is based on the effectiveness of the vaccine in preventing varicella and its complications, as well as the need to minimize the number of injections by using combination vaccines whenever possible.

Conclusion Not Needed, Direct Answer Provided Above

From the Research

Administering a Third Dose of Varicella Vaccine

• The available evidence does not directly address the administration of a third dose of varicella vaccine within 21 days of the second booster dose, given 5 years after the initial dose at 1 year of age 2, 3, 4, 5, 6.
• Studies have investigated the effectiveness of second-dose varicella vaccination as post-exposure prophylaxis 2, the optimal timing of the second dose 3, and the immunogenicity and safety of varicella vaccines in different populations 4, 5, 6.
• However, the specific scenario of administering a third dose within 21 days of the second booster dose is not explicitly discussed in the provided studies.
• As a result, there is no clear evidence to determine whether administering a third dose of varicella vaccine in this manner would cause any issues 2, 3, 4, 5, 6.

Relevant Findings

• A study on the immunogenicity and safety of a live-attenuated varicella vaccine in healthy adolescents and adults found that a two-dose schedule with an interval of 10 weeks induced high immune responses without increased safety risk 4.
• Another study on the immunogenicity and safety of a booster dose of live attenuated varicella vaccine in children aged 2 to 6 years found that a booster dose recalled specific immune response to varicella-zoster virus with no safety concerns increased 6.
• However, these findings do not directly apply to the scenario of administering a third dose within 21 days of the second booster dose.

Limitations

• The available evidence does not provide sufficient information to determine the safety and efficacy of administering a third dose of varicella vaccine within 21 days of the second booster dose 2, 3, 4, 5, 6.
• Further research would be necessary to investigate this specific scenario and provide evidence-based guidance.