Routine Asymptomatic SARS-CoV-2 Screen Testing of Ontario Long-Term Care Staff After COVID-19 Vaccination

Abstract

SARS-CoV-2 screen testing is routine serial testing of asymptomatic individuals outside of outbreak or known exposure settings to identify staff infectious with SARS-CoV-2 and exclude them from work. Routine asymptomatic screen testing of staff has been proposed as a potential mitigating strategy to reduce SARS-CoV-2 introduction and transmission in long-term care (LTC) homes. A rapid review of the literature found no real-world evidence to either support or refute screen testing in preventing LTC home COVID-19 outbreaks. There are several direct harms associated with screen testing, as well as opportunity costs, including exacerbating LTC staffing shortages. On the basis of the evidence reviewed, and given the high rates of protection of COVID-19 vaccines against symptomatic and asymptomatic SARS-CoV-2 infection, the potential harms and costs of screen testing among vaccinated LTC home staff likely outweigh the benefits.

Multicenter Postimplementation Assessment of the Positive Predictive Value of SARS-CoV-2 Antigen-Based Point-of-Care Tests Used for Screening of Asymptomatic Continuing Care Staff

“…Many reports of asymptomatic SARS-CoV-2 testing campaigns using either APOCTs or rRT-PCR tests have demonstrated low test positivity rates, suggesting high-volume testing of asymptomatic individuals is of low yield ( 19 – 22 ). Another Canadian study evaluating universal APOCT screening of HCWs in continuing care also found a similar APOCT positivity rate of 0.16% ( 23 ). The prevalence of positive results in our cohort was similar at 0.12%; however, the true prevalence of disease in our cohort is much less if true positives are accounted for (0.05%).…”

Multi-centre post-implementation evaluation of SARS-CoV-2 antigen-based point of care tests used for asymptomatic screening of continuing care healthcare workers

“…Many reports of asymptomatic SARS-CoV-2 testing campaigns using either APOCT or rRT-PCR tests have demonstrated low test positivity rates, suggesting high volume testing of asymptomatic individuals is of low yield [19][20][21][22]. Another Canadian study evaluating universal APOCT screening of HCWs in continuing care also found a similar APOCT positivity rate of 0.16% [23]. The prevalence of positive results in our cohort was similar at 0.12%, however the true prevalence of disease in our cohort is much less if true positives are accounted for (0.05%).…”

Impact of Hospital Visitor Restrictions during the COVID-19 Pandemic

“…Data from asymptomatic serial screening of unvaccinated long-term care (LTC) staff in Ontario revealed low rates of positive results (<0.4%), even during periods where prevalence was high. 12 Published studies from the first wave of the pandemic demonstrate that the risk posed by family/essential caregivers is low. Early in the pandemic, prior to the widespread implementation of public health and IPAC measures, a systematic review of nosocomial acquisition of SARS-CoV-2 from case series in Wuhan, China demonstrated that 2% of nosocomial acquired cases were from visitors.…”