A cluster-randomized clinical trial finds that adoption of onsite polymerase chain reaction (PCR) testing for COVID-19, influenza, and respiratory syncytial virus (RSV) in Canadian nursing homes (NHs) could avert four emergency department (ED) transfers per 100 beds, or roughly 64,000 transfers, each respiratory virus season.

The reduction in ED transfers stemmed from increased viral testing, improved case detection, and faster initiation of antiviral therapy for flu rather than reduced outbreak number or size, according to the authors, who were led by researchers at Michael Garron Hospital in Toronto.

The team conducted the trial in 20 Toronto NHs with a total of 3,963 beds (median, 5.5 units, 30 beds per unit) to assess whether use of onsite PCR could shrink respiratory illness outbreaks and improve resident outcomes during the 2024-25 respiratory virus season.

NHs were randomly assigned to use a PCR instrument or provide standard of care from November 2024 to May 2025. The facilities were matched by average crowding index scores and scaled bed size, and resident vaccination rates were similar between the intervention and control groups.

The findings were published yesterday in JAMA Internal Medicine.

Shorter test turnaround time

Effective respiratory virus surveillance in NHs relies on prompt symptom recognition and viral testing results, the authors noted. 

“Despite improvements to syndromic surveillance, test turnaround time (TAT) from specimen collection to the results of respiratory multiplex polymerase chain reaction (RMPCR) takes days due to specimen transport and processing at a reference laboratory,” they wrote. 

“Point-of-care (POC) respiratory virus testing in NHs has the potential to mitigate the effect of respiratory outbreaks through enhanced IPAC [infection prevention and control] and clinical management,” they added.

The researchers noted a pilot study recently published in Infection Control & Hospital Epidemiology by many of the same researchers, which found that NH staff could be trained to use a POC PCR instrument, markedly reducing TAT and time to identification of outbreaks. 

Averted transfers driven by COVID rather than flu 

In total, respiratory infections were detected in 937 residents, including 695 with a confirmed infection on PCR, along with 242 suspected infections that included residents without a positive test result who were transferred to an ED or died. 

Viral testing rates (3.69 vs 1.73 tests per week) and ratio of confirmed to suspect cases (4.2 vs 2.0) were higher in intervention NHs, along with a shorter time from symptom onset to initiation of antiviral therapy (−2.5 days).

Testing of asymptomatic exposed residents accounted for 40 of 695 confirmed cases (6%), with 36 in the intervention group and four among controls. In addition to SARS-CoV-2, influenza, and RSV, there were 27 confirmed infections (3.4%) with other respiratory viruses, including nine in control NHs and 18 in intervention homes.

The joint estimate of outbreak number (51 and 62, respectively) and size for the intervention group was the same as those of controls, with a rate ratio of 1.12. COVID-19 outbreaks were most common (median, seven and 6.5 cases in the control and intervention groups, respectively). ED transfers for confirmed (−3.5%) and confirmed/suspected infections (−11.0%) were lower among intervention NHs and didn’t affect death rates. 

This difference equates to four fewer ED transfers per 100 beds. In a subgroup analysis by virus, the averted ED transfers were driven by COVID-19 (absolute difference, −19.5%) rather than flu (−2.7%).

Time from symptom onset to antiviral initiation was shorter in intervention NHs than control NHs for flu (0.5 vs 2.9 days) but not for COVID-19, which the authors said likely had a secondary role in averted ED transfers. 

“The lack of difference in time to initiation of antiviral therapy for SARS-CoV-2 was possibly related to the use of RATs [rapid antigen tests] in control homes,” they wrote. “The absence of substantial change in deaths is likely due to low event rates but could be magnified during seasons with a higher case fatality rate or future pandemics.”

In the subset of NHs in which all viral tests counted, the testing rate was more than double in intervention NHs than in controls (3.69 vs 1.73 tests/week).

“Not only was testing 2-fold higher, the increased ratio of confirmed to suspected infections indicated better case detection,” the researchers wrote. “By comparison, the case numbers from NHs in the control group were underestimated, given the high percentage positivity among the respiratory virus tests collected. True case numbers likely differed substantially, and the imbalance in case ascertainment contributed to the negative primary outcome.”

Less hospital-related functional decline

The authors acknowledged the fixed upfront costs of POC PCR instruments and ongoing cartridge costs but said the direct savings from fewer ED transfers would exceed those costs. 

“The estimated avoided ED transfers observed in our study translated to approximately 8,000 across Canada, 19,000 in the UK [United Kingdom], and 64,000 across the US each season,” they wrote. “During seasonal hospital surges, these avoided ED transfers could improve health care capacity” and would make respiratory virus testing more equitable among NH residents.

In a related commentary, Alison O’Donnell, MD, MPH, of the Veterans Affairs Pittsburgh Healthcare System, and Robin Jump, MD, PhD, of the University of Pittsburgh, said that averting hospital transfers maintains the cognitive and psychological benefits of staying in a familiar and homelike environment. 

It also “reduces the risk of functional decline, delirium, iatrogenesis [medically related complications], and other adverse events associated with hospitalizations,” they wrote.