Increased reactions to pediatric influenza vaccination following concomitant pneumococcal vaccination

Area of Science:

• Pediatric immunology
• Vaccinology
• Public health

Background:

• Influenza in children leads to significant illness, hospitalizations, and mortality, especially in those under five.
• Pediatric influenza vaccination programs have faced challenges, including a suspension in Western Australia due to observed febrile convulsions.
• Previous vaccination campaigns, like the 2009 H1N1 vaccine in New Brunswick, highlighted the need for ongoing safety monitoring.

Purpose of the Study:

• To conduct enhanced post-marketing surveillance of seasonal influenza vaccines in children.
• To monitor local and general reactions following pediatric influenza vaccination.
• To establish a baseline for rapid assessment of vaccine safety in children.

Main Methods:

• Parents of children receiving influenza vaccine at dedicated clinics were provided with survey kits.
• Surveys collected data on local and general symptoms experienced by children up to three days post-vaccination.
• Enhanced surveillance focused on monitoring reactions in a pediatric population.

Main Results:

• Fever (≥ 38°C) occurred in less than 10% of children receiving their first dose of seasonal influenza vaccine (n=660).
• Severe febrile incidents (≥ 39°C) were uncommon, and no cases of febrile convulsions were reported.
• Concurrent administration with other vaccines, such as conjugated pneumococcal vaccine, was associated with increased reactogenicity.

Conclusions:

• Seasonal influenza vaccines are safe for pediatric use.
• Parents should be informed about the potential for increased fever, especially when other vaccines are administered concurrently.
• Consideration of antipyretics may be beneficial for managing post-vaccination fever in children.