Kyler Baughman came home from his job early the day after Christmas because he was feeling under the weather. He had a cough and told his fiancee, Olivia Marcanio, that his chest hurt, she told WPIX. A day prior, his mother, Beverly Baughman, said he had had a “snotty nose.” By Thursday he was dead, the cause was complications from the flu virus, his mom told WPIX.

While unexpected, Baughman’s story is like that of many others who succumb to the flu, or complications the potentially deadly virus can cause. Symptoms of the flu, like body aches and congestion or a cough, can sometimes be written off as a bad cold, but the infection actually leads to thousands of deaths each year, according to Centers for Disease Control data. For some people, plenty of fluids and rest is enough to put them on the mend but others aren’t so lucky.

There isn't data on exactly how many people die each year of the flu. States aren’t required to report the cases or deaths of those over the age of 18, additionally, when someone dies of complications from the flu, it frequently goes unlisted on the death certificate.

While the flu and a common cold are both respiratory illnesses, their root causes are different, meaning the actual virus that causes the symptoms and illness differ. Usually, symptoms from the flu are worse than those of a cold. The flu usually comes with body aches, a muscle and body aches, headaches, fatigue, and in some cases (but not all) a fever and chills, according to the CDC.

Complications from the flu, like those Baughman experienced, are usually the cause of flu-related deaths. Those complications include more moderate complications like sinus or ear infections, or more severe complications like pneumonia, inflammation of the heart, brain, or muscles, and even multi-organ failure, according to the CDC.

In some extreme cases, the flu can cause sepsis. This is the body’s way of reacting to an infection that has gone untreated or that hasn’t been stopped. It happens when an infection that’s already in a person’s body, in the case of the flu usually a respiratory infection, causes the whole body to react by releasing chemicals into the bloodstream to fight the infection, according to Mayo Clinic. That chemical then causes inflammatory responses and then those can cause damage through the body and can eventually lead to death. When detected early, sepsis can sometimes be treated with the aggressive use of antibiotics and medicine to stabilize the body's functions.

Those at the highest risk of complications due to the flu are small children, pregnant women, and those over the age of 65.