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• COVID-19 poses significant infection control challenges in psychiatric facilities. • Its impact varied across psychiatric specialties and according to age. • Psychogeriatric, specialized, and adolescent units experienced high infection rates. • Infection control strategies evolved in response to viral transmission trends. • Tailored infection control measures are essential for psychiatric settings. The coronavirus disease 2019 (COVID-19) pandemic posed unprecedented infection control challenges for psychiatric facilities. We examined 4-year COVID-19 infection control challenges in acute psychiatric care (general adult, closed, adolescent, and psychogeriatric units) and residential psychiatric care (medicalized and specialized facilities) from week 11 of 2020 to week 20 of 2024. RT-PCR and antigen rapid diagnostic tests (Ag-RDTs) were analyzed according to admission timing, age, sex, wave patterns, care settings, and outbreaks. Of the 6,552 RT-PCR tests and 3,314 Ag-RDTs, 502 (7.7%) and 38 (1.1%) were positive, respectively. In multivariable analysis adjusted for age, sex, and care setting, increasing age and admission to closed units were independently associated with SARS-CoV-2 positivity, whereas the psychogeriatric setting was not. Outbreak investigations accounted for 361 (66.9%) cases, while 179 (33.1%) were non-outbreak cases. Psychogeriatric units were the most affected (median of 4 outbreaks per unit), compared to 3 in closed units, 2 in adolescent, general adult, and medicalized care units, and 1 in specialized care units (p = 0.01). Outbreak infection rates were lower in general adult (25.0%, N = 193) and medicalized care units (28.6%, N = 127), and higher in adolescent (76.9%, N = 21), specialized (72.5%, N = 78), and psychogeriatric units (50.0%, N = 225) (p < 0.01), with closed units showing intermediate rates (39.0%, N = 244). Nosocomial COVID-19 is common in psychiatric settings, and effective risk management strategies for airborne diseases must be tailored to psychiatric care settings, patient behaviors, and rapid control measures.