The flu (influenza) is a seasonal virus that causes mild to severe symptoms. Some people recover in about a week, while others can be at risk of serious, life-threatening complications. There are many strains of the virus.
The risk of complications increases if you’re over the age of 65. Older adults tend to have a weaker immune system, naturally occurs as we age. And when your immune system isn’t robust, it becomes harder for the body to fight off a virus.