Heterogeneous rebound patterns of foodborne diseases after COVID-19 non-pharmaceutical interventions, South Korea, 2005-2024.

OBJECTIVES

To characterize pathogen-specific patterns of foodborne diseases across the full COVID-19 pandemic period, including post-non-pharmaceutical intervention (NPI) relaxation through 2024.

METHODS

We conducted interrupted time series analysis of 12 nationally notifiable foodborne diseases using 20 years of data (2005-2024) from South Korean surveillance systems. Segmented negative binomial regression models were applied with February 2020 as the intervention point.

RESULTS

Four distinct response patterns emerged: sustained decrease (typhoid fever), post-COVID rebound (7 diseases including norovirus), no significant effect (3 diseases), and paradoxical increase (Vibrio vulnificus). Seven diseases with declining pre-pandemic trends showed post-NPI rebounds, while diseases already increasing showed no significant changes. Norovirus demonstrated the strongest rebound pattern.

CONCLUSIONS

COVID-19 NPIs did not produce uniform foodborne disease reductions. Most declining diseases shifted to increasing post-pandemic trends, suggesting pandemic-era food delivery and consumption changes may have worsened trajectories. These heterogeneous patterns underscore the need for pathogen-specific surveillance strategies for future pandemic preparedness.