Does Norovirus infection always cause fever?

Generally speaking, fever refers to an elevated body temperature. Norovirus infection does not necessarily cause fever, and this primarily depends on individual differences. If the body's immunity is weak, fever may occur; however, if the immune system is strong and the amount of norovirus is small, fever may not develop. If discomfort occurs, prompt medical attention is recommended. Detailed explanation is as follows:

Fever may occur if the body's immunity is weak. After norovirus infects the human body, it stimulates the immune system to mount a response to eliminate the virus. During this process, the immune system releases certain cytokines, such as interleukin-1 and tumor necrosis factor. These cytokines act on the hypothalamic thermoregulatory center, causing the body's temperature set point to rise, which leads to an increase in body temperature and results in fever. Typically, fever associated with norovirus infection may appear within the first 1-2 days of illness. Body temperature may reach 38°C or higher, and may be accompanied by systemic symptoms such as fatigue and muscle pain.

However, if the number of noroviruses is low or the individual's immunity is strong, the immune system may rapidly control viral replication and spread, resulting in relatively mild stimulation of the body. In such cases, significant elevation in body temperature may not occur, and only mild gastrointestinal symptoms may be present, such as slight nausea, vomiting, or diarrhea.

In daily life, attention should be paid to food hygiene, avoiding consumption of raw or undercooked food. Frequent handwashing, ensuring the safety of food and water, and avoiding close contact with infected individuals are also important preventive measures.