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The following is a summary of “Four COVID-19 screening strategies for early case identification within the homeless shelter population: a cluster randomized controlled trial,” published in the December 2024 issue of Infectious Disease by Mokashi et al. 

Researchers conducted a retrospective study to compare the effectiveness of 4 surveillance strategies for detecting SARS-CoV-2 within the homeless shelter population in Hamilton, ON, and to assess participant adherence over time for each method.  

They performed the study in 11 homeless shelters from April 2020 to January 2021. Participants who consented and took part in surveillance were eligible for self-swabbing. The primary outcome was SARS-CoV-2 detection, while secondary outcomes included outbreaks, adherence, and acceptability. All participants, including staff and residents, underwent daily symptom surveillance by shelter staff. Shelters were assigned to 1 of 3 asymptomatic surveillance arms: once-weekly self-collected oral swabs (OS), once-weekly self-collected oral-nasal swabs (ONS), or once-weekly nurse-collected nasopharyngeal swabs (NPS), or a symptomatic-only testing arm.  

The results showed that 9,747 SARS-CoV-2 tests were conducted on 1,570 participants. Of these, 4,527 were allocated to OS collection, and 4,935 to ONS collection. A total of 285 participants were assigned to NPS collection before discontinuation. The OS group identified 5 new cases (1.1 per 1000; 95% CI 0.4–2.3), while the ONS group identified 15 new cases (3.0 per 1000; 95% CI 1.9–4.7), resulting in a risk ratio (RR) of 2.76 (95% CI 1.00–7.58; P = 0.040). However, the mixed-effects model exhibited no significant difference in positivity rates between ONS and OS (OR]1.64; 95% CI 0.76–9.14; P = 0.129). Both ONS and OS were preferred over NPS, which detected no cases due to low adherence; 3 outbreaks were reported, the second with 2 positive cases each and the third having 3 positive cases.  

Investigators concluded the 2 self-collection strategies outperformed others, with ONS showing superior or non-inferior results in all measures and were now studying its large-scale implementation across multiple homeless shelters. 

Source: bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-024-10148-y