Reactogenicity of a three-dose pertussis acellular vaccine catch-up in children 21-40 months of age

Area of Science:

• Pediatrics
• Immunology
• Public Health

Background:

• Pertussis remains a concern in populations with low vaccination rates.
• Acellular pertussis (aP) vaccines offer a safer alternative to whole-cell vaccines.
• Evaluating catch-up immunization strategies is crucial for disease control.

Purpose of the Study:

• To assess the reactogenicity of a three-dose catch-up acellular pertussis (aP) immunization schedule.
• To identify factors associated with adverse events following immunization in young children.

Main Methods:

• A cohort of children aged 21-40 months received a three-dose catch-up aP vaccination.
• Adverse events, including fever and local reactions, were monitored.
• Statistical analysis was performed to identify risk factors for reactogenicity.

Main Results:

• The aP vaccination was well-tolerated, with fever (≥38°C) occurring in 5% of doses and local reactions in 14-15%.
• Adverse event onset was not linked to age, dose interval, or prior pertussis antibodies.
• Non-buttock injection sites and prior similar symptoms increased reactogenicity.

Conclusions:

• Catch-up aP immunization demonstrates a favorable safety profile in children over one year old.
• These findings support the consideration of catch-up vaccination campaigns to reduce pertussis circulation in under-vaccinated areas.
• Targeted strategies can enhance the safety and effectiveness of pertussis control efforts.