When the influenza virus enters the body, it triggers an inflammatory response that leads to the characteristic flu symptoms. The immune system produces a flood of chemicals that cause blood vessels to become leaky, allowing immune cells to travel to the site of infection and attack the virus. This process also causes muscle and joint aches, which are intensified by increased nerve sensitivity due to inflammation.
Understanding the role of inflammation in flu symptoms can help explain why over-the-counter pain relievers, which reduce inflammation, can help alleviate some of the discomfort. Additionally, this knowledge can inform the development of new treatments for the flu that target the inflammatory response itself.