Chills During Infection Resolution
Chills are a symptom of active infection, not a sign that infection is leaving your body. Chills occur during the acute phase of infection when your body is actively fighting pathogens, not during recovery.
Understanding When Chills Occur
Chills represent your body's response to infection onset and active disease, occurring when endogenous pyrogens (like interleukin-1 and tumor necrosis factor) act on your hypothalamus to increase core body temperature. 1 This is a physiological mechanism to enhance immune response, not an indicator of infection resolution.
Timing of Chills in Infection
- Chills typically occur at the beginning or during active infection, particularly with bacterial infections and bacteremia 2, 3
- In influenza, chills affect approximately 70% of patients during the acute illness phase, alongside fever, cough, and myalgia 4
- The more severe the chills (especially "shaking chills"), the higher the likelihood of serious bacterial infection, with shaking chills conferring a 12.1-fold increased risk of bacteremia compared to no chills 3
What Chills Actually Indicate
When you experience chills with fever, this signals active infection requiring immediate evaluation, not infection resolution:
- Shaking chills have a specificity of 90.3% and positive likelihood ratio of 4.65 for bacteremia 3
- Patients with shaking chills and at least one abnormal vital sign have an odds ratio of 5.9 for bacteremia 5
- Chills combined with fever warrant blood culture collection before antibiotics, as this represents a high-risk presentation 6
Clinical Implications
If you develop new or worsening chills during what you thought was recovery, this suggests either:
- Persistent active infection requiring medical evaluation 4
- Development of a complication such as secondary bacterial pneumonia (which typically occurs 4-5 days after initial illness onset) 4
- Bacteremia or systemic spread of infection 2, 3
When to Seek Immediate Care
Seek urgent medical attention if chills are accompanied by: 6
- Hemodynamic instability or persistent hypotension
- Oxygen saturation <92%
- Confusion or altered mental status
- Signs of organ dysfunction
- Severe thrombocytopenia
Common Misconception
The belief that "chills mean the infection is breaking" is medically incorrect. Chills are part of the acute inflammatory response to infection, mediated by cytokines that reset your hypothalamic temperature set-point upward 1. Recovery from infection is typically marked by resolution of symptoms including chills, not their appearance or intensification.