Non-pharmaceutical interventions (NPIs) to control influenza spread among children in primary school and kindergarten: class-suspension or symptom-based isolation?

Background Non-pharmaceutical interventions (NPIs) are critical for influenza control and prevention, however, the data about such interventions are insufficient among students in grades below middle school. Hence, this study aims to explore the effectiveness of NPIs (class-suspension and symptom-based isolation) on the control of influenza spread among children in primary school and kindergarten. Findings will support evidence-based strategies for influenza control among children enrolled in primary schools and kindergartens. Methods We purposively selected two regions (Zigong and Nanan) in Southwest China as study places, and class-suspension and symptom-based isolation was conducted in the two regions, respectively. RT (effective reproduction number) value, incidence cases, and attack rate were considered as outcome indicators. R4.1.2 software was used to conduct statistical analysis, and p < 0.05 (two-tailed) was considered as statistically significant. Results In total, 593 students in the Nanan district received symptom-based isolation while 1340 students in Zigong city received class-suspension. The vaccination rate of Zigong (21.27%) was much greater than Nanan (8.26%) (p < 0.001). Parents in the Nanan were more highly educated, with undergraduate, master and above degrees, compared to parents in the Zigong (p < 0.05). Though there was no statistical significance difference in RT between Nanan (1.23) and Zigong (1.16) after quarantine and control measures were conducted, the RT value in the two regions was sharply decreased. The incident cases after class-suspension was much higher than symptom-based isolation in both kindergarten and primary school. The attack rate had a significant difference between class-suspension and symptom-based isolation in primary school (p < 0.05). Conclusions Both symptom-based isolation and class-suspension are effective measures in control of influenza spread, and symptom-based isolation are more effective than class-suspension in primary school. Health education and daily surveillance are needed in the control and prevention of influenza.