The common cold and the flu may seem similar at first. They are both respiratory illnesses and can cause similar symptoms. But different viruses cause these two conditions. Your symptoms will help you tell the difference between the two.

Both a cold and the flu share a few common symptoms. People with either illness often experience:

• a runny or stuffy nose
• sneezing
• body aches
• general fatigue

As a rule, flu symptoms are more severe than cold symptoms.

Another distinct difference between the two is how serious they are. Colds rarely cause other health conditions or problems. But the flu can lead to sinus and ear infections, pneumonia, and sepsis.

To determine whether your symptoms are from a cold or from the flu, you need to see your doctor. Your doctor will run tests that can help determine what’s behind your symptoms.

If your doctor diagnoses a cold, you’ll only need to treat your symptoms until the virus has run its course. These treatments can include using over-the-counter (OTC) cold medications, staying hydrated, and getting plenty of rest.

Taking an OTC flu medicine early in the virus’ cycle may also help. Rest and hydration are also beneficial for people with the flu. Much like the common cold, the flu just needs time to work its way through your body.

Common symptoms of the flu include:

Fever: The flu almost always causes an increase in your body temperature. This is also known as a fever. Most flu-related fevers range from a low-grade fever around 100°F (37.8°C) to as high as 104°F (40°C). Although alarming, it’s not uncommon for young children to have higher fevers than adults. If you suspect your child has the flu, see your doctor.

You may feel “feverish” when you have an elevated temperature. Symptoms include chills, sweats, or being cold despite your body’s high temperature. Most fevers last for less than one week, usually around three to four days.

Cough: A dry, persistent cough is common with the flu. The cough may worsen, becoming uncomfortable and painful. You may also experience shortness of breath or chest discomfort during this time. Many flu-related coughs can last for about two weeks.

Muscle aches: These flu-related muscle pains are most common in your neck, back, arms, and legs. They can often be severe, making it difficult to move even when trying to perform basic tasks.

Headache: Your first symptom of the flu may be a severe headache. Sometimes eye symptoms, including light and sound sensitivity, go along with your headache.

Fatigue: Feeling tired is a not-so-obvious symptom of the flu. Feeling generally unwell can be a sign of many conditions. These feelings of tiredness and fatigue may come on fast and be difficult to overcome.

Influenza is a serious virus that leads to many illnesses each year. You don’t have to be young or have a compromised immune system to get ill from the infection. Healthy people can get sick from the flu and spread it to friends and family. In some cases, the flu can even be deadly. Flu-related deaths are most common in people over age 65.

The best and most efficient way to avoid the flu and prevent spreading it is to get a vaccination. The flu vaccine is available as an injectable shot. The more people vaccinated against the flu, the less the flu can spread.

How does the flu shot work?

To make the vaccine, scientists select the strains of the flu virus that research suggests will be the most common in the coming flu season. Millions of vaccines with those strains are produced and distributed.

Once you receive the vaccine your body begins producing antibodies against those strains of the virus. These antibodies provide protection against the virus. If you come into contact with the flu virus at a later point, you can avoid an infection. You may get sick If you end up coming into contact with a different strain of the virus. But the symptoms will be less severe because you had the vaccination.

Who should get the flu shot?

Doctors recommend that everyone over the age of 6 months receive the flu vaccine.

This is especially true for people in high-risk categories, like:

• adults over age 65
• women who are pregnant
• children under age 5
• people with weakened immune systems due to chronic illness

Most doctors also recommend everyone gets their flu vaccine by the end of October. This way your body has time to develop the right antibodies before flu season kicks into gear. It takes about two weeks for antibodies to develop against the flu after vaccination.

Most people will recover from the flu in about one week. But it may take several more days for you to feel back to your usual self. It’s not uncommon for you to feel tired for several days after your flu symptoms have subsided.

It’s important you stay home from school or work until you haven’t had a fever for at least 24 hours. This is without taking fever-reducing medications. If you have the flu, you’re contagious a day before your symptoms appear and up to five to seven days afterward.

Many people report avoiding the flu vaccine each year for fear that it will make them sick. It’s important to understand that the flu vaccine can’t cause you to develop the flu. You aren’t going to become sick because you received the vaccine.

Flu vaccines contain dead or weakened strains of the flu virus. These strains aren’t strong enough to cause an illness.

You may experience some side effects from the flu shot. These side effects are often mild and only last a short period of time. The side effects of a shot outweigh the possible symptoms of a flu infection later.

The most common side effects of the flu shot include:

• soreness around the flu shot injection site
• low-grade fever in the days immediately following the injection
• mild aches and stiffness

Any side effects that do occur often only last a day or two. Many people won’t experience any side effects.

On rare occasions, some people may have a serious allergic reaction to the vaccination. If you’ve had an allergic reaction to any vaccine or medication before, talk with your doctor.

Most cases of the flu are mild enough that you can treat yourself at home without prescription medications.

It’s important you stay home and avoid contact with other people when you first notice flu symptoms.

You should also:

• Drink plenty of fluids. This includes water, soup, and low-sugar flavored drinks.
• Treat symptoms such as headache and fever with OTC medications.
• Wash your hands to prevent spreading the virus to other surfaces or to other people in your house.
• Cover your coughs and sneezes with tissues. Immediately dispose of those tissues.

If symptoms become worse, call your doctor. They may prescribe an antiviral medication. The sooner you take this medicine, the more effective it is. You should start treatment within 48 hours from when your symptoms start.

Contact your doctor as soon as symptoms appear if you’re at high risk for flu-related complications. These high-risk groups include:

• people with weakened immune systems
• women who are pregnant
• people over age 65
• children under age 5