# Surge in macrolide dispensing to Swiss children in a period of increased incidence of Mycoplasma pneumoniae detection: an interrupted time-series analysis

## TL;DR

Swiss children saw a sharp rise in macrolide antibiotic use in late 2023, likely due to increased Mycoplasma pneumoniae infections.

## Contribution

This study provides empirical evidence of a surge in macrolide prescriptions in Swiss children linked to rising Mycoplasma pneumoniae cases.

## Key findings

- Macrolide use increased by 235% in Swiss children aged 0 to 11 years from October 2023.
- Amoxicillin use remained stable during the same period, suggesting a specific shift toward macrolides.
- The rise in macrolide prescriptions coincided with a global increase in Mycoplasma pneumoniae infections.

## Abstract

To evaluate the trend in macrolide ambulatory use among children in Switzerland following a global surge in Mycoplasma pneumoniae infections in late 2023.

We conducted a population-based interrupted time-series analysis of macrolide use in Swiss children aged 0 to 11 years from 2018 to 2023 using national ambulatory antibiotic claims data. The main outcome was the evolution of macrolide use in ambulatory setting, expressed as monthly defined daily doses (DDD) per 1000 children. We defined two time periods: (i) the pre-autumn 2023 period, before M. pneumoniae detections increased in Switzerland (1 January 2018 to 30 September 2023) and (ii) the autumn 2023 period, after M. pneumoniae detections increased in Switzerland (1 October 2023 to 31 December 2023). We built a quasi-Poisson regression model to estimate the changes in macrolide monthly DDD per 1000 children from October 2023 in Switzerland. The model accounted for temporal trends before the WHO alert and for the seasonal pattern of macrolide prescriptions. We analysed amoxicillin use as a control outcome.

We found a significant increase in macrolides use expressed in monthly DDD per 1000 children aged 0 to 11 years from October 2023 in Switzerland [+235% (95%CI +139%–+368%), P value < 0.001]. The use of amoxicillin remained stable in both age groups after October 2023.

We found a 3-fold increase in macrolide monthly DDD per 1000 children in autumn 2023 in the context of a global increase in M. pneumoniae infections. Monitoring macrolide resistance and promoting appropriate prescription practices are essential.