Epidemiological characteristics and environmental contamination of monkeypox in Beijing's Chaoyang district: Field evidence from 2023 to 2024.

OBJECTIVES

The mpox outbreak in Beijing's Chaoyang District after late May 2023, this study aims to evaluate the epidemiological characteristics and environmental contamination of this outbreak.

METHODS

A field investigation was conducted to evaluate the epidemiological characteristics of mpox cases and their living environments in Chaoyang District, Beijing, between May 2023 and May 2024. Laboratory testing, epidemiological description, and statistical analysis were conducted subsequently.

RESULTS

The outbreak resulted in 43 non-fatal cases, 97.67 % were Men who have Sex with Men (MSM) and symptomatic, tracking a peak in August 2023 and declining thereafter. Travel history was reported in 27.91 % (12 of 43), and coinfections with both HIV and syphilis were among 16.28 % of mpox cases. MPXV-positive rates were 97.67 % for rash swabs, 55.81 % for throat swabs, and 59.38 % for environmental samples. Median cycle threshold (Ct) values were 20.45 (IQR: 4.57) for rash swabs, 31.59 (IQR: 5.64) for throat swabs, and 33.33 (IQR: 4.37) for environmental samples. Contact tracing revealed a 9.09 % prevalence among close contacts and a secondary attack rate of 10.26 %. High environmental contamination was found in bedrooms and items such as electronics and cups.

CONCLUSIONS

The mpox outbreak in Beijing's Chaoyang District predominantly affected MSM, that transmitted through diverse transmission routes. Environmental contamination in long-lived rooms or used items highlights the importance of targeted hygiene measures.