EPIDEMIOLOGICAL FEATURES OF ACUTE AIRBORNE INFECTIONS IN PRESCHOOL CHILDREN ATTENDING ORGANIZED CHILDCARE FACILITIES

Abstract

Objective: To characterize the epidemiology, etiological structure, and key risk factors for acute airborne infections (AAIs) among preschool children attending organized childcare facilities. Methods: We conducted a prospective cohort study in 12 municipal childcare centers in [City, Country] over a 12-month period (September 2023 – August 2024). A cohort of 510 children aged 3-6 years was enrolled. Active surveillance for AAIs (defined as new onset of fever, cough, rhinitis, or pharyngitis) was maintained via parental reporting and weekly checks by a research nurse. Nasopharyngeal swabs were collected during AAI episodes and analyzed using a multiplex RT-PCR panel for 18 respiratory pathogens. Baseline questionnaires captured data on risk factors (e.g., age, vaccination status, number of siblings, class size). Results: A total of 2,185 AAI episodes were recorded, corresponding to a high incidence rate of 4.28 episodes per child-year. The incidence was highest in winter (December-February; 7.1 episodes/child-year). At least one pathogen was identified in 71.5% of samples. The most common pathogens were Rhinovirus (39.0% of all episodes), Adenovirus (15.2%), Parainfluenza viruses (11.8%), and seasonal Influenza A/B (9.0%, highly seasonal). Vaccine-preventable diseases were detected: 5 cases of Varicella (chickenpox) and a 3-case outbreak of Measles were identified, all in unvaccinated or incompletely vaccinated children. Significant risk factors for increased AAI frequency included: younger age (3 years vs. 5 years, RR: 1.62), larger class size (>20 children, RR: 1.45), and the presence of older siblings (RR: 1.30). Conclusion: Preschool children in organized childcare settings experience a very high, polymicrobial burden of airborne infections, dominated by non-vaccine-preventable viruses like Rhinovirus. Daycare characteristics, such as class size, are significant predictors of infection risk. These findings underscore the critical importance of multi-pronged prevention: strict adherence to vaccination schedules (especially for Measles, Varicella, and Influenza), coupled with robust non-pharmaceutical interventions (hand hygiene, ventilation, and cohorting) in the childcare environment.