Regional Synchrony of COVID-19 Peaks and Mycoplasma Pneumoniae-Attributed Mortality Troughs and Rebounds in Children Aged 0–19 Years: a Systematic Analysis of the Global Burden of Disease Study 2023 in 204 Countries and Territories

Background: Mycoplasma pneumoniae, a leading cause of paediatric community-acquired pneumonia, nearly disappeared under COVID-19 non-pharmaceutical interventions and re-emerged with a delay relative to other respiratory pathogens. Whether its timing tracks national and regional COVID-19 waves has not been quantified globally. Methods: From the Global Burden of Disease Study 2023 Results Tool we extracted, for 204 countries and seven GBD super-regions, deaths and disability-adjusted life years (DALYs) at ages 0–19 years from lower respiratory infections attributable to Mycoplasma pneumoniae (2019–2023) and deaths and incident cases of COVID-19 (2020–2023; 2019 set to zero by definition). For each geography we located the COVID-19 peak year, the Mycoplasma trough (minimum 2020–2023) and the post-trough rebound maximum, computed the peak-to-peak interval, and tested Spearman correlations between COVID-19 peak intensity and trough depth or rebound amplitude, with lagged z-score cross-correlations and alternative COVID-19 calibres (all-ages deaths; 0–19-year incidence) as sensitivity analyses. Results: Globally, Mycoplasma-attributed deaths at ages 0–19 years fell from 27,388 in 2019 to a trough of 22,711 in 2021 (−17.1%) and partially recovered to 26,366 in 2023 (−3.7% versus 2019), while paediatric COVID-19 deaths peaked at 147,850 in 2021. The modal interval from the COVID-19 peak to the Mycoplasma rebound peak was +2 years in five of seven super-regions and in 115 of 204 countries (56%; median 2 years). COVID-19 peak intensity showed no significant correlation with trough depth or rebound amplitude (|r| ≤ 0.21; p ≥ 0.09). Because rebound maxima fell in 2023—the final data year—in six of seven super-regions, the +2-year interval is partly a right-censoring artefact. The pattern strengthened under all-ages COVID-19 mortality (64% of countries at +2 years), shifted to +1 year under 0–19-year incidence, and was unchanged under the DALY calibre. Conclusions: Paediatric Mycoplasma-attributed mortality troughs followed COVID-19 mortality peaks with a modal two-year lag, consistent with suppression and delayed re-emergence under pandemic interventions, but with no detectable intensity gradient. The timing signal is robust to all-ages mortality calibration, calibre-dependent for incidence, and bounded by right-censoring at 2023; continued surveillance is required to observe complete rebound cycles.