Infect Chemother . SARS-CoV-2 Breakthrough Infections and Reinfections in Patients with Severe Mental Illness during Three Omicron Outbreaks

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Infect Chemother


. 2026 Jun;58(2):259-263.
doi: 10.3947/ic.2025.0147.
SARS-CoV-2 Breakthrough Infections and Reinfections in Patients with Severe Mental Illness during Three Omicron Outbreaks

Chih-Chia Huang ^{1 2}


Affiliations

• PMID: 42405547
• DOI: 10.3947/ic.2025.0147

Abstract

Patients with severe mental illness (SMI) in psychiatric facilities face unique vulnerabilities to severe acute respiratory syndrome coronavirus-2 infection. We conducted an study in a female-only, closed psychiatric ward from February 2020 to December 2023, documenting three coronavirus disease 2019 outbreaks during BA.2, BA.5, and XBB-predominant periods. During the first outbreak, 98.0% of residents were infected, including 97.7% of vaccinated individuals. The second outbreak resulted in 28.6% infections, with 25.5% experiencing presumed reinfection. The third outbreak affected 78.0% of residents. All infections were mild with no hospitalizations or deaths. These findings highlight the vulnerability of institutionalized SMI populations.

Keywords: Breakthrough infections; COVID-19; Reinfections; SARS-CoV-2; Severe mental illness.