Hong Kong's Centre for Health Protection reported one imported dengue fever case between September 18 and September 24; the patient had visited Malaysia during the incubation period. The city has recorded 32 dengue cases so far this year, comprising 30 imported and two local cases, compared with 59 cases last year, all imported, and 161 cases in 2024, including five local infections. Globally, the World Health Organization recorded over 14 million dengue cases in 2024, over five million cases and over 4,000 related deaths in 2025, and around 2.2 million cases and over 1,000 deaths from January to August 2026. Several nearby destinations have reported large caseloads this year, including Sri Lanka and Vietnam with over 90,000 cases each, and Cambodia, Indonesia and Malaysia with over 70,000 each. Guangdong Province recorded 431 cases as of August 31, 2026.

No new chikungunya cases were recorded in the same week. Hong Kong has confirmed three cases this year, two imported and one local, after 82 confirmed cases last year, of which 11 were local. For the local case involving a woman living in Tai Kok Tsui, the centre said that as of 5pm on September 25 it had assessed over 3,200 people residing or working in the district and identified no new cases. Three people with mild symptoms were arranged for blood tests, which were negative for the virus. The centre urged people who live in or visited the vicinity of Li Tak Street, Cherry Street Park and Lok Kwan Street Park to maintain hygiene and seek medical advice if they develop fever, rash or joint pain.