The epidemiology of Mycoplasma pneumoniae infections in 2023 and hypothesis of "Immunity Debt": A single-center correlation analysis of the post-COVID-19.

OBJECTIVE

To investigate the epidemiological characteristics of Mycoplasma pneumoniae (MP) infection in our hospital in 2023 and explore the relationship with underlying "immunity debt" by comparing positive rates before and after COVID-19 prevention and control measures.

METHODS

A total of 12504 patients with respiratory diseases were included, and age, gender, and month were analyzed for their association with MP infection. The effect of COVID-19 prevention and control was evaluated by comparing positive rates from 2018 to 2023.

RESULTS

In 2023, the MP-positivity rate peaked in October at 59.18% (390/659) and was predominantly seen in pediatric patients. In addition, comparison with previous years revealed a higher infection rate in children aged 0-3 years in 2023. A significant difference was observed in positive rates before, during, and after COVID-19 prevention and control, with the highest rate post-control; and females had a higher infection rate in all three periods. In a word, the 2023 MP-positive rates surge, the marked increase in susceptibility among children aged 0-3, and the consistently higher infection rate in females.

CONCLUSION

The study suggests a significant increase in MP positive rates, particularly in pediatric patients and females in 2023. The implementation of COVID-19 prevention and control measures may have contributed to the higher infection rate observed after its removal. In conclusion, the 2023 MP epidemic represents a significant shift in post-pandemic infectious disease dynamics. Understanding this surge may require a comprehensive view within a Multifactorial Framework which contain Natural Epidemic Cycle, The "Immunity Debt" Hypothesis and Behavioral and Ecological Factors.