Impact of Fever Thresholds in Detection of COVID-19 in Department of Veterans Affairs Community Living Center residents

Taissa Bej MS; Sonya Kothadia MD, MS; Brigid M. Wilson PhD; Sunah Song MS; Janet M. Briggs RN, NP; Richard E. Banks BS; Curtis J. Donskey MD; Federico Perez MD, MS; Robin L. P. Jump MD, PhD


J Am Geriatr Soc. 2021;69(11):3044-3050. 

In This Article

Abstract and Introduction


Background: Among nursing home residents, for whom age and frailty can blunt febrile responses to illness, the temperature used to define fever can influence the clinical recognition of COVID-19 symptoms. To assess the potential for differences in the definition of fever to characterize nursing home residents with COVID-19 infections as symptomatic, pre-symptomatic, or asymptomatic, we conducted a retrospective study on a national cohort of Department of Veterans Affairs (VA) Community Living Center (CLC) residents tested for SARS-CoV-2.

Methods: Residents with positive SARS-CoV-2 tests were classified as asymptomatic if they did not experience any symptoms, and as symptomatic or pre-symptomatic if the experienced a fever (>100.4°F) before or following a positive SARS-CoV-2 test, respectively. All-cause 30-day mortality was assessed as was the influence of a lower temperature threshold (>99.0°F) on classification of residents with positive SARS-CoV-2 tests.

Results: From March 2020 through November 2020, VA CLCs tested 11,908 residents for SARS-CoV-2 using RT-PCR, with a positivity of rate of 13% (1557). Among residents with positive tests and using >100.4°F, 321 (21%) were symptomatic, 425 (27%) were pre-symptomatic, and 811 (52%) were asymptomatic. All-cause 30-day mortality among residents with symptomatic and pre-symptomatic COVID-19 infections was 24% and 26%, respectively, while those with an asymptomatic infection had mortality rates similar to residents with negative SAR-CoV-2 tests (10% and 5%, respectively). Using >99.0°F would have increased the number of residents categorized as symptomatic at the time of testing from 321 to 773.

Conclusions: All-cause 30-day mortality was similar among VA CLC residents with symptomatic or pre-symptomatic COVID-19 infection, and lower than rates reported in non-VA nursing homes. A lower temperature threshold would increase the number of residents recognized as having symptomatic infection, potentially leading to earlier detection and more rapid implementation of therapeutic interventions and infection prevention and control measures.


The pandemic caused by SARS-CoV-2 disproportionately affects nursing home residents. Although only 4% of COVID-19 cases in the United States occurred among nursing home residents and the staff who care for them, as of February 2021, this group accounted for 32% of COVID-19 related deaths in the country.[1] Age, comorbid illness, and inherent frailty likely explain the high mortality rates observed among nursing home residents. Especially early in the pandemic, additional factors that contributed to poor outcomes in this vulnerable population including limitations in the supply of personal protective equipment (PPE) and delays in the availability of SARS-CoV-2 testing and test results. Compounding these factors are age-related physiologic changes that can obscure or blunt signs and symptoms of infection, leading to delays in recognizing residents with COVID-19 infections. In particular, the use of a temperature threshold of 100.4°F may not be sensitive enough to detect nursing home residents with fever as a symptom of COVID-19 and who should undergo further assessment and testing for SARS-CoV-2.[2]

Early descriptions of COVID-19 infection in community nursing homes characterized residents as either symptomatic or asymptomatic at the time of testing, with >50% of those with RT-PCR tests that were positive for SARS-CoV-2 in the latter category.[3,4] Within days of a positive test, however, most individuals who were initially asymptomatic went on to develop symptoms that included fever (>100.0°F), malaise, and cough. A subsequent evaluation of COVID-19 infections among residents of a large academic nursing home reported similar findings.[5] Overall, the majority of residents who were asymptomatic at the time of testing eventually developed symptoms and thus were deemed as pre-symptomatic; less than 15% of residents with a positive SARS-CoV-2 test remained asymptomatic.[3–5]

A lower temperature threshold to define a fever may improve recognition of nursing home residents as having symptoms of COVID-19 infection. Screening criteria described early in the pandemic suggested using a temperature of 99.5°F to assess for fever among frail elders living in congregate care settings.[6,7] Based in part on data describing residents of Department of Veterans Affairs (VA) nursing homes, commonly termed Community Living Centers (CLCs), from March 1 through May 14, 2020, McConeghy et al. proposed using a temperature threshold of 99.0°F to define fever when screening for SARS-CoV-2 among nursing home residents.[8] Here, we compare using a temperature of >100.4°F compared to assess the >99.0°F when screening for COVID-19 infections among a national cohort of VA CLC residents during the first 9 months of the pandemic.