How many days does it usually take to recover from a low fever after receiving a tetanus shot?

Under normal circumstances, low-grade fever following tetanus vaccination is usually a normal immune response triggered by the vaccine. It typically resolves on its own within 1–3 days, although the exact duration may vary depending on individual physical condition and care measures. Here's a detailed explanation:

From the perspective of cause, the tetanus vaccine acts as a foreign antigen. Once introduced into the body, it stimulates the immune system to mount a response, which may include a mild increase in body temperature. The temperature usually stays between 37.3°C and 38°C. This is a common adverse reaction and not caused by infection, so there is no need for excessive concern.

If an individual has good physical health and normal immune function, and ensures adequate rest, drinks plenty of warm water, avoids fatigue and cold exposure during the period of low fever, body temperature usually returns to normal within 1–2 days. However, for those with weaker constitutions, older individuals, or those who remain physically active, have irregular diets, or fail to take proper care during the fever, recovery may take up to about 3 days, though it generally does not exceed this timeframe.

It should be noted that if the low-grade fever persists beyond 3 days, or if body temperature rises above 38.5°C, especially when accompanied by worsening redness, swelling, and pain at the injection site, dizziness, fatigue, or other abnormal symptoms, the condition may not be a simple vaccine reaction. In such cases, prompt medical evaluation is necessary to identify the underlying cause.