Abstract:
Objective To understand the epidemiology of an outbreak of Mycoplasma pneumoniae pneumonia in a primary school in Shenzhen, Guangdong province, in 2023, provide evidence of field prevention and control of the similar epidemic in future.
Methods The information about basic characteristics, symptoms and signs of the cases were collected. The field hygienic investigation, field detection (air speed, temperature, humidity) and retrospective cohort study were carried out. Throat swabs were collected to detect M. pneumoniae DNA.
Results A total of 52 M. pneumoniae pneumonia cases were identified, and the attack rate was 4.80%. The main clinical manifestations were cough (98.08%) and fever (92.31%). The epidemic curve showed a value-added pattern, and the outbreak lasted 73 days. The first case occurred on April 16, 2023. The cases gathered in the 2nd floor and in the building A. Field detection displayed that the air speed of building A was significantly lower than that of building B (0.06±0.05 m/s vs. 0.12±0.09 m/s; t=−2.219, P=0.041). The differences in the air speed were significant (F=4.030, P=0.033) among different floors, the ventilation of the 2nd floor was the worst. Poor ventilation layout was fund in building A and the 2nd floor. Retrospective cohort studies suggested that chess game was the risk factor (relative risk= 4.00, 95% confidence interval: 1.08−14.82). In the 38 throat swabs, 8 were positive in the DNA detection of M. pneumoniae. The outbreak was effectively controlled after two closed-loop responses (risk analysis + proposed measures + tracking).
Conclusion This was an outbreak of M. pneumoniae pneumonia, which might be transmitted by droplets. It is suggested to carry out risk assessment, conduct timely case reporting and isolation and strengthen ventilation and personal protection.
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