Likelihood of SARS-CoV-2 transmission in multi-bedded patient rooms by infecting variant.

OBJECTIVE

Sharing a room with an unrecognized contagious patient poses the greatest in-hospital risk of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study quantified secondary attack rates associated with exposure to the SARS-CoV-2 Omicron subvariant in an oncology centre.

METHODS

Patients with hospital-onset SARS-CoV-2 infection from 2021 to 2024 were evaluated for roommate exposure, with secondary attack rates stratified by the predominant circulating variant.

RESULTS

Among 299 patients who shared a room with a patient with hospital-onset SARS-CoV-2 infection, 17% developed secondary infection. Attack rates did not differ between the pre- and post-Omicron periods. Nearly half of the secondary cases were asymptomatic and, if unrecognized, could contribute to onward transmission within the hospital setting.

CONCLUSIONS

High-risk hospital exposure to SARS-CoV-2 warrants monitoring for secondary infection to prevent onward transmission in vulnerable patients.