Medically reviewed by Isabel Casimiro, MD
The flu (short for influenza) is a common respiratory virus that causes symptoms such as fever, cough, body aches, chills, extreme fatigue, and sometimes, vomiting and diarrhea. Unlike the common cold, flu symptoms tend to be more severe and come on all at once.
Flu symptoms can temporarily impair your ability to carry out daily tasks and prevent you from going to school or work. Generally, the flu can last anywhere from five to seven days. But, a variety of factors, like having underlying health conditions, the symptoms you’re experiencing, and how much rest you’re getting can affect the duration of your illness.
What Is the Flu?
The flu is a respiratory illness that occurs when you contract an influenza virus. These types of viruses predominantly affect the lungs, nose, and throat.
People who have the flu can unintentionally spread the illness to you via fluid droplets when they cough, sneeze, talk, or laugh near you. The droplets can land in your mouth or nose if you’re within six feet of them. You might also develop the illness if you inhale flu germs or touch contaminated surfaces and then make contact with your mouth, nose, or eyes. As a result, the virus can multiply in your body and lead to the onset of symptoms.
Symptoms usually start a couple of days after the virus invades your respiratory tract—which includes your mouth, nose, throat, and lungs. Everyone experiences the flu a little differently. Some people may have mild symptoms that last a handful of days, while others can experience more severe symptoms that can last a week or longer.
Types of Flu
There are two main types of flu: type A and type B. Influenza type A tends to be more common and severe in adults, while influenza is less common and primarily affects young children. Type A viruses are also responsible for some kinds of animal flu, such as swine flu or bird flu. Type B viruses, on the other hand, usually only infect humans.
While colds are more common, the flu is widespread and crops up in every part of the world. The Centers for Disease Control (CDC) estimates that this illness affects millions of people a year in the United States alone. From 2021 to 2022, 9 million people had the flu, 100,000 of those people had to be hospitalized, and 5,000 people unfortunately passed away as a result of their symptoms.
The Flu vs. COVID-19
The flu shares similar symptoms with COVID-19, but the two illnesses are caused by different viruses. COVID-19 seems to spread more easily, makes people contagious for longer, and can lead to severe illness more often. Early studies also suggest that it may take longer for people who contract COVID-19 to show symptoms.
However, both illnesses do share some symptoms. Both the flu and COVID-19 can cause:
It’s often difficult to tell the difference between the flu and COVID-19. That’s why it may help to get tested to see what infection you have and which treatments you should use to help relieve symptoms. It’s also worth noting that you can have both illnesses at the same time. In some cases, you can have one or both of the illnesses without displaying any symptoms at all.
Both the flu and COVID-19 can also occasionally lead to more serious complications. These include pneumonia, secondary infections, heart conditions, and respiratory (lung-related) issues. Unlike the flu, COVID-19 can also sometimes lead to blood clots.
Stages of the Flu
It’s important to note that medical tests can detect the flu in your system the day before you begin showing symptoms, and five to seven days after symptoms go away. People with weakened immune symptoms and young children, however, may stay contagious even longer.
There are a few stages of the flu you might go through when you have the illness. These include:
- Day 0: Otherwise known as the day you contract the virus. Usually, you don’t have any symptoms or may be unaware of your illness.
- Day 1: Your body starts gradually developing symptoms. You may wake up feeling fine, but as the day progresses, you might develop chills, body aches, or fever.
- Day 2: This is the first day that the flu takes a stronger toll on your body, leading to more classic symptoms such as coughing, a sore throat, a runny nose, and fatigue.
- Day 3: Generally, this day is when flu symptoms tend to peak. You may not be able to get out of bed, experience the most severe symptoms, or spend the day sleeping and recovering.
- Day 4: Symptoms may slowly start to decrease as your immune system becomes better accustomed to the virus. You will likely still feel very fatigued, but you may be experiencing less fever and congestion.
- Day 5: Typically, most people on day five start to feel better. You might still have a cough and feel the need to blow your nose, but it may be easier to get out of bed and complete some daily tasks.
- Day 6: Your symptoms may feel at bay and you might have residual effects of the flu, such as a light cough. However, it’s advised to stay at home until day seven of the infection as you still might be contagious and can infect other people with the virus.
- Day 7: By the time you reach day seven, you are able to go out into public. However, it’s important to take precautions such as practicing healthy handwashing habits, covering your mouth when you sneeze or cough, or wearing a mask.
In some cases, young children and those who are pregnant or have weakened immune systems may continue to have symptoms after a week of the illness. If you or a loved one still have symptoms after a week, it doesn’t hurt to call a healthcare provider and let them know that symptoms aren’t improving. Your provider can help guide you to other treatment options or ask you to come in for a physical exam if they suspect complications, such as pneumonia.
Who Might Experience Severe Symptoms?
Most people weather the flu and feel back to normal within a week of the infection. But, some people might be at an increased risk of developing serious complications. If you’re in one of the following groups, you are more likely to experience more severe illness:
- People ages 65 and older
- Children under the age of five
- Pregnant people or those who have given birth in the past two weeks
- Adults in group homes or nursing homes
- Those who smoke tobacco
Certain conditions also boost your risk of having more severe symptoms, such as:
- Chronic pulmonary disease
- Long-term aspirin therapy in people ages 19 or younger
- Metabolic disorders like diabetes
- Sickle-cell anemia
How Long Is The Flu Contagious?
You are contagious a day or more before you show symptoms and up to a week after they’re gone. You’re at your most contagious three to four days after you first start experiencing and displaying flu symptoms.
It’s worth noting that it’s easy to spread the infection to people you work with, live with, or frequently socialize with or see. Similarly, the people you spend time with often can just as easily spread the illness to you. However, you can prevent transmitting the virus to others and protect yourself by practicing the following strategies:
- Practicing habits like getting enough sleep and sanitizing surfaces at home and at work
- Washing your hands often
- Covering your nose and mouth with the inside of your elbow or a tissue when talking, sneezing, or coughing
- Staying home when you are sick
- Avoiding close contact with others
- Trying not to touch your eyes, nose, or mouth
- Getting the flu vaccine each year
Can You Make Flu Symptoms Go Away Faster?
There’s usually not much you can do about your symptoms other than rest, stay hydrated, and let symptoms run their course. You may consider some treatment options like over-the-counter flu medicines or getting a prescription antiviral drug from a healthcare provider. Generally, these medications are only effective if you take them within the first 24 to 48 hours of having symptoms.
However, medication can help you avoid serious complications, especially if you are in a high-risk group. That said, letting your healthcare provider know about your illness can help you get treatment sooner.
When to Contact a Healthcare Provider
Generally, it’s not always necessary to tell your healthcare provider if you get the flu. However, it’s good practice to contact your provider if you:
- Are pregnant
- Live with an underlying health condition or autoimmune disorder
- Are over the age of 65
- Have a young child under the age of 5
- Experience flu symptoms for longer than one week
A Quick Review
The flu is a common, seasonal illness that affects millions of people each year. Your symptoms can show up within a day of infection and last anywhere from a few days to a week or longer. It’s common to experience symptoms such as coughing, fever, chills, fatigue, and body aches when you have the flu.
Unfortunately, there isn’t much you can do to shorten the course of the illness. However, getting proper rest, asking your provider for antiviral medications, and staying hydrated can help you recover. You can also be contagious even after symptoms go away, so practicing prevention strategies can reduce the risk of transmitting the infection to others.
Read the original article on Health.com.