Most people associate COVID-19 with a fever, which is the body’s typical immune response to a viral invader. This elevated temperature signals that the immune system is actively fighting the infection. However, some individuals, particularly those with severe illness, experience the opposite: an unusually low body temperature. This presentation deviates from the expected course of the infection. A low temperature is a less frequent but concerning sign that requires immediate attention.
Defining Low Body Temperature in COVID-19
A normal human body temperature is generally around 98.6°F (37°C), though this naturally fluctuates throughout the day. When monitoring for illness, a temperature drop below the normal range signals a potential problem. Clinically, a body temperature that falls below 95°F (35°C) is classified as hypothermia.
In COVID-19 patients, this decrease may appear either as the initial symptom or as a drop following a period of high fever. A low temperature indicates that the body’s ability to regulate its internal heat has become compromised. Recognizing this threshold is important, as temperatures slightly below normal, such as 96.5°F, can still be a significant marker of systemic infection.
Biological Reasons for Temperature Drops
The shift from fever to low temperature is rooted in the body’s systemic response to severe infection, which overwhelms normal regulatory systems. One primary mechanism involves widespread inflammation caused by the virus, which can lead to sepsis. Sepsis is a life-threatening condition where the body’s response to infection damages tissues and organs. In about 10% of sepsis cases, this results in hypothermia instead of fever.
Another explanation focuses on the virus’s impact on the central nervous system, specifically the hypothalamus. The hypothalamus acts as the body’s thermostat, controlling temperature regulation. SARS-CoV-2 may enter the brain, possibly through the olfactory nerve pathway, causing dysfunction in the area that contains warm-sensitive neurons. This interference can disrupt the body’s ability to maintain its set temperature, leading to a drop in core body heat.
Lower body temperatures may also facilitate the virus’s ability to thrive. Studies suggest that even small temperature decreases near the normal 98.6°F (37°C) can substantially increase the stability and replication rate of SARS-CoV-2. A reduced core temperature may enable more rapid viral growth, contributing to a higher viral load and more severe disease progression.
What Low Temperature Signals About Illness Severity
When a low body temperature occurs with a COVID-19 infection, it signals that the patient’s condition is potentially severe. The presence of hypothermia forms part of the diagnostic criteria for conditions like Systemic Inflammatory Response Syndrome. It suggests the body is struggling to mount an effective defense, which is a worrying prognostic indicator.
In hospitalized patients, hypothermia is associated with poorer outcomes, especially for those in the intensive care unit. Patients presenting with a low temperature are more likely to require longer periods of mechanical ventilation and extended ICU stays. Research indicates that low body temperature is associated with an increased risk of mortality compared to patients who are normothermic or febrile.
Home Management and Medical Consultation
If a low temperature is detected during an illness, immediate steps should be taken to help the body conserve and generate heat. This includes covering the person with extra blankets or layers of clothing and offering warm, non-alcoholic fluids. Monitoring the temperature regularly is important to track any decline or improvement.
A persistent or significantly low temperature with COVID-19 requires urgent medical attention. If the temperature drops to or below 95°F (35°C), or if the patient exhibits concerning symptoms like confusion, difficulty breathing, or an inability to warm up, emergency services should be contacted immediately. Professional medical intervention is necessary to stabilize the patient and address the underlying severe infection.