Hong Kong's Centre for Health Protection reported 12 community-acquired Legionnaires' disease cases for August 16 to 22, 2026, the Department of Health said on August 24. The cases involved eight males and four females aged between 37 and 93, with patients living across the Eastern, Tai Po, Sha Tin, Central and Western, Tuen Mun, Yuen Long, Kowloon City and Southern districts. Most had underlying illnesses.

An initial investigation found the cases were sporadic, and no epidemiological linkages had been established with other previously confirmed cases in Hong Kong. The CHP was conducting investigations to identify potential sources of infection and high-risk exposure.

The CHP said Legionnaires' disease incidence is linked to ambient temperature, with more cases in warmer summer months. As of August 22, 131 cases had been recorded in 2026, compared with 167 in 2025 and 135 in 2024.

The department reminded the public to maintain man-made water systems properly, noting that Legionella bacteria grow well in warm water of 20 to 45 degrees Celsius and may spread through contaminated droplets and mist. It advised susceptible groups, including immunocompromised people, to follow precautions such as using sterile or boiled water in humidifiers and avoiding mist-generating devices where possible.