Free-living core body temperature monitoring using a wrist-worn sensor after COVID-19 booster vaccination: a pilot study

Abstract

Core body temperature (CBT) is a key vital sign and fever is an important indicator of disease. In the past decade, there has been growing interest for vital sign monitoring technology that may be embedded in wearable devices, and the COVID-19 pandemic has highlighted the need for remote patient monitoring systems. While wrist-worn sensors allow continuous assessment of heart rate and oxygen saturation, reliable measurement of CBT at the wrist remains challenging. In this study, CBT was measured continuously in a free-living setting using a novel technology worn at the wrist and compared to reference core body temperature measurements, i.e., CBT values acquired with an ingestible temperature-sensing pill. Fifty individuals who received the COVID-19 booster vaccination were included. The datasets of 33 individuals were used to develop the CBT prediction algorithm, and the algorithm was then validated on the datasets of 17 participants. Mean observation time was 26.4 h and CBT > 38.0 °C occurred in 66% of the participants. CBT predicted by the wrist-worn sensor showed good correlation to the reference CBT (r = 0.72). Bland–Altman statistics showed an average bias of 0.11 °C of CBT predicted by the wrist-worn device compared to reference CBT, and limits of agreement were − 0.67 to + 0.93 °C, which is comparable to the bias and limits of agreement of commonly used tympanic membrane thermometers. The small size of the components needed for this technology would allow its integration into a variety of wearable monitoring systems assessing other vital signs and at the same time allowing maximal freedom of movement to the user.

Validity of the CALERA Research Sensor to Assess Body Core Temperature during Maximum Exercise in Patients with Heart Failure

“…Based on the manufacturer, the CALERA Research sensor has functionalities and services tailored for scientific studies. A recent study analyzed the performance of CALERA Research in 33 healthy individuals who had received COVID-19 vaccinations [15]. The results showed that the limits of agreement were between −0.67 • C and +0.93 • C, which is comparable to the bias and limits of agreement found in commonly used tympanic membrane thermometers.…”

“…The results showed that the limits of agreement were between −0.67 • C and +0.93 • C, which is comparable to the bias and limits of agreement found in commonly used tympanic membrane thermometers. According to the Bland-Altman statistics, the CALERA Research device worn on the wrist predicted an average bias of 0.11 • C for core body temperature when compared to the reference method for measuring the Tc [15].…”

“…For patients with CHF, who face a high risk for heat illness or must work in hot conditions, having access to a non-invasive sensor that can alert them to changes in their Tc is particularly important. The CALERA Research sensor, a product of greenTEG A.G. based in Rümlang, Switzerland, is an example of such technology and is now available on the commercial market [15]. The CALERA Research sensor was built on the technology that powered its prototype, the CORE sensor.…”

Analytical Analysis of Factors Affecting the Accuracy of a Dual-Heat Flux Core Body Temperature Sensor

“…One direction is research of construction or technological modification, for example by developing flexible sensors [ 24 , 25 ], reducing sensitivity to convective conditions [ 26 ], or adapting sensors to the system requirements of the Internet of Things (IoT) [ 27 ]. Another fast-growing research area is the usability of such technology in clinical [ 28 , 29 ], sport [ 30 ], work safety [ 27 ] or free-living [ 26 , 31 ] applications. It is worth noting that new patents are also being sought, which confirms the commercial sector’s interest in this technology [ 32 ].…”