Early Temperature Trends May Identify COVID-19 Infection in Pre-Symptomatic Long-Term Care Residents

BACKGROUND:
Early-detection strategies for COVID-19 include systematic temperature and symptom screening. However, pre-symptomatic transmission in nursing homes is common and older patients often have blunted febrile response to infection. As a result, current clinical screening for temperature above 38°C may not identify infected subclinical cases that risk transmission until later. Further, more than one million nursing home residents get daily symptom screening for a condition that remains asymptomatic 40% of the time in unvaccinated residents and over 80% of the time in those with breakthrough infection. This retrospective cohort study sought to determine whether early temperature trends in the course of COVID-19 infection could identify pre-symptomatic Veterans in nursing homes. Using VA data, investigators identified 6,176 residents of VA nursing homes during the study period (March 1 to December 13, 2020) who underwent COVID testing triggered by symptoms and modeled what would have happened if different metrics were used to screen them for COVID. They also examined age and other demographics, baseline temperature, and comorbidities.

FINDINGS:

• A change in temperature of 0.4°C from baseline identified 47% of VA nursing home residents who became COVID positive, earlier than standard testing by an average of 42 hours.
• Temperature variability of 0.5°C over three days, when paired with a 37.2°C temperature cutoff (instead of the VA standard of 38°C), identified 55% of VA nursing home residents who became COVID positive earlier than standard testing by an average of 44 hours.
• A change from baseline temperature of 0.4°C, when combined with temperature variability of 0.7°C over three days, identified 52% of VA nursing home residents who became COVID positive, earlier than standard testing by an average of 40 hours, and by more than 3 days in 22% of Veterans.

IMPLICATIONS:

• This study presents a method that leverages single daily temperatures to identify who to screen and test for infection with a potential for earlier detection by several days, which may lead to better infection control and reduce the need for facility-wide “sweep” testing in nursing homes.  

LIMITATIONS:

• VA Community Living Centers follow CDC guidelines for infection control practices. If CDC recommended changing the practice of temperature thresholds, including establishing baseline temperatures, then system-wide resources for education, electronic medical record programming, and infection control process development will be required.  

AUTHOR/FUNDING INFORMATION:
This study was partly funded by HSR&D. Messrs. DeVone and Halladay, and Drs. Bayer, McConeghy, Singh, Nanda, Rudolph (Director), and Gravenstein are part of HSR&D’s Center of Innovation in Long-Term Services and Supports for Vulnerable Veterans (LTSS).

Elhamamsy S, DeVone F, Bayer T, Halladay C, Cadieux M, McConeghy K, Rajan A, Sachar M, Mujahid N, Singh M, Nanda A, McNicoll L, Rudolph JL, Gravenstein S. Can we use temperature measurements to identify pre-symptomatic SARS-CoV-2 infection in nursing home residents? Journal of the American Geriatrics Society. August 4, 2022; online ahead of print.