Influenza vaccine effectiveness in primary school children in Japan: a prospective cohort study using rapid...

Area of Science:

• Public Health
• Epidemiology
• Vaccinology

Background:

• Influenza poses a significant public health burden, necessitating effective vaccination strategies.
• Estimating vaccine effectiveness (VE) is crucial for assessing vaccine performance and informing public health policy.
• School-aged children are a key demographic for influenza transmission and vaccination campaigns.

Purpose of the Study:

• To estimate the influenza vaccine effectiveness (VE) in school children aged 6-12 years.
• To utilize a low-cost prospective cohort study design incorporating rapid diagnostic tests.
• To analyze VE for overall influenza, influenza A, and influenza B.

Main Methods:

• Prospective cohort study involving 2607 primary school children in Tsuchiura City, Japan.
• Data collection via baseline questionnaires for vaccination status and risk factors.
• Influenza diagnosis confirmed by rapid diagnostic tests for symptomatic children during the 2006-2007 winter season.
• Logistic regression analysis to adjust for confounders and calculate VE.

Main Results:

• The attack rate for influenza A was 5.4% and for influenza B was 11.9%.
• Overall influenza VE was estimated at 21% (95% CI: -8 to 42).
• VE for influenza A was 44% (95% CI: 8 to 66), while VE for influenza B was 5% (95% CI: -37 to 34).

Conclusions:

• The study demonstrated a low-cost method for estimating influenza VE using readily available data from rapid diagnostic tests.
• Potential factors contributing to the observed low VE include the sensitivity of rapid tests and differential healthcare-seeking behaviors.
• Further research is needed to address limitations and improve the accuracy of VE estimates in similar settings.