JMIR Publications

ABSTRACT

Background:

From medication usage to time-of-day, many factors can alter body temperature (BT), even in the absence of underlying pathology. In select cases, medical guidance suggests consideration of clinical and demographic factors when interpreting BT. Environmental factors such as ambient temperature are also known to alter BT. However, the effects are small. It remains unclear if such data impacts real-world healthcare practices.

Objective:

Because fever was a primary symptom that triggered diagnostic testing for COVID-19, this manuscript leverages statewide test results from the COVID-19 pandemic to assess whether higher ambient temperatures are associated with lower test positivity rates, as environmentally-mediated BT increases would not reflect pathology.

Methods:

Aggregating California testing and climate data, a mixed-effects Beta-regression model estimated daily positivity rates as a function of ambient temperature, population, testing day of the week, and COVID prevalence across 58 counties during the 133 days between widespread testing availability and vaccine approval.

Results:

Results highlighted a significant negative association with ambient temperature which was not present in a sensitivity analysis using random daily temperatures.

Conclusions:

This work illustrates the impact of environmental factors on an essential public health activity and calls for an assessment of whether environmental context can be used to improve interpretation of patient data.