Global Varicella Vaccine Effectiveness: A Meta-analysis

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Varicella vaccines are globally available, with national programs typically employing 1- or 2-dose schedules.
• Understanding vaccine effectiveness is crucial for public health policy and disease prevention strategies.

Purpose of the Study:

• To evaluate postlicensure estimates of varicella vaccine effectiveness (VE) in healthy children.
• To synthesize existing data on the efficacy of varicella vaccination schedules.

Main Methods:

• A systematic review and meta-analysis of studies published between 1995 and 2014.
• Inclusion criteria focused on original data of dose-specific varicella VE in immunocompetent children.
• Random effects models were used to pool estimates by disease severity and dose number.

Main Results:

• One dose of varicella vaccine showed 81% effectiveness against all varicella and 98% against moderate/severe cases.
• Effectiveness did not significantly vary by vaccine type or study design for a single dose.
• The pooled two-dose VE against all varicella was 92%.

Conclusions:

• One dose of varicella vaccine is moderately effective against all varicella and highly effective against moderate to severe varicella.
• A second dose of the vaccine provides enhanced protection against all forms of varicella.
• Findings support the use of both one and two-dose varicella vaccination schedules.