Comparing flu, COVID, cold and RSV: Understanding the differences and how to protect yourself
Flu, COVID-19, the common cold and RSV have similarities, but they differ in their severity, contagiousness and symptoms.
Vaccines are available for COVID-19, the flu and RSV.
However, there is no cure for the common cold.
Here's a look at what you need to know about how to stay healthy from the flu, COVID-19, the common cold and RSV:
What is influenza (flu)?
While seasonal influenza (flu) viruses are detected year-round in the United States, the U.S. Centers for Disease Control and Prevention (CDC) says flu viruses typically circulate in the fall and winter during what’s known as the flu season.
What's the timing of flu season?
The exact timing and duration of flu season varies. However, flu activity often begins to increase in October. Most of the time flu activity peaks between December and February, although significant activity can last as late as May.
Since the start of the COVID-19 pandemic, the timing and duration of flu activity has been less predictable.
The overall health impact – infections, hospitalizations, and deaths – of flu varies from season to season.
How to avoid getting the flu
The CDC says the best way to reduce your risk from seasonal flu is to get vaccinated every year. Flu vaccines help to reduce the burden of flu illnesses, hospitalizations and deaths on the health care system each year. Also, the CDC said anyone 6 moths and older should get an annual flu vaccine by the end of October.
There are also several preventive actions people can take to stop the spread of germs. They include:
- Avoid close contact with people who are sick.
- If you are sick, limit contact with others as much as possible to keep from infecting them.
- Cover coughs and sneezes: Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
- Wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
- Avoid touching your eyes, nose and mouth. Germs spread this way.
- Clean and disinfect surfaces and objects that may be contaminated with viruses that cause flu.
- For the flu, the CDC recommends that people stay home for at least 24 hours after their fever is gone except to get medical care or other necessities. Fever should be gone without the need to use a fever-reducing medicine. Note that the stay-at-home guidance for COVID-19 may be different.
If you are sick with the flu, antiviral drugs can be used to treat your illness if your doctor prescribes them.
What is COVID-19?
COVID-19 is a disease caused by a virus named SARS-CoV-2. It can be very contagious and spreads quickly. The CDC reports more than 1 million people have died from COVID-19 in the United States.
COVID-19 most often causes respiratory symptoms that can feel much like a cold, the flu or pneumonia. COVID-19 may attack more than your lungs and respiratory system. Other parts of your body may also be affected by the disease. Most people with COVID-19 have mild symptoms, but some people become severely ill.
Some people with minor or no symptoms can develop post-COVID conditions known as “Long COVID.”
How COVID-19 spreads
COVID-19 spreads when an infected person breathes out droplets and very small particles that contain the virus. Other people can breathe in these droplets and particles, or these droplets and particles can land on their eyes, nose or mouth. In some circumstances, these droplets may contaminate surfaces they touch.
Anyone with COVID-19 can spread it even if they don’t have symptoms.
How to protect yourself from COVID-19
There are several ways to protect yourself, your household and your community from severe illness from COVID-19.
The CDC recommends basic health and hygiene practices like:
- Handwashing
- Staying up to date with COVID-19 vaccines
- Improving ventilation
- Getting tested for COVID-19 if needed
- Following recommendations for what to do if you have been exposed
- Staying home if you have suspected or confirmed COVID-19
- Seeking treatment if you have COVID-19 and are at high risk of getting very sick
- Avoiding contact with people who have suspected or confirmed COVID-19
In September, the U.S. government relaunched a program to provide free COVID-19 home tests to Americans.
Although vaccinated people sometimes get infected with the virus that causes COVID-19, the CDC says staying up to date on COVID-19 vaccines significantly lowers the risk of getting very sick, being hospitalized or dying from COVID-19.
Similarities and differences between the flu and COVID-19
Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a coronavirus (SARS-CoV-2) first identified in 2019. Flu is caused by infection with a flu virus.
The CDC says COVID-19 spreads more easily than the flu.
Compared with flu, COVID-19 can cause more severe illness in some people. Compared to people with flu, people infected with COVID-19 may take longer to show symptoms and may be contagious for longer periods of time.
According to the CDC, you can’t tell the difference between flu and COVID-19 by the symptoms alone.
Specific testing is needed to tell what the illness is and confirm a diagnosis.
If a person has COVID-19, it could take them longer from the time of infection to experience symptoms than if they have flu.
Flu: Typically, a person may experience symptoms anywhere from one to four days after infection.
COVID-19: Typically, a person may experience symptoms anywhere from two to five days, and up to 14 days after infection.
What is a common cold?
A common cold is a mild upper respiratory illness that resolves in a short period of time.
The CDC states symptoms of a cold usually peak within two to three days. They can include:
- Sneezing
- Nasal congestion
- Sore throat
- Cough
- Fever
When viruses that cause colds first infect the nose and sinuses, the nose makes clear mucus.
After two or three days, mucus may change to a white, yellow or green color.
More than 200 viruses can cause a cold, but rhinoviruses are the most common type. Viruses that cause colds can spread from person to person through the air and close personal contact.
No cure for the common cold
There is no cure for a cold. It will get better on its own without antibiotics. Antibiotics won’t help you get better if you have a cold.
Seek help from a health care professional if you have:
- Trouble breathing or fast breathing
- Dehydration
- Fever that lasts longer than four days
- Symptoms that last more than 10 days without improvement
- Symptoms, such as fever or cough, that improve but then return or worse
- Worsening of chronic medical conditions.
How to feel better from a cold
The CDC recommends:
- Getting plenty of rests
- Drink plenty of fluids
- Use a clean humidifier or cool mist vaporizer
- Use saline nasal spray or drops
- Breathe in steam from a bowl of hot water or shower
- Use throat lozenges or cough drops. However, do not give lozenges to children younger than 4 years old.
- Use honey to relieve cough for adults or children at least 1 year of age or older.
Cold prevention
Preventative tips include:
- Clean your hands
- Avoid close contact with people who have colds or other upper respiratory infections
- Cover your mouth and nose when coughing or sneezing
- Avoid touching your eyes, nose and moth with unwashed hands
- Don’t smoke and avoid secondhand smoke
- Stay at home while you are sick and keep children out of school or day care while they are sick.
What is Respiratory Syncytial Virgus (RSV)?
The CDC says Respiratory Syncytial Virgus (RSV) is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious. Infants and older adults are more likely to develop severe RSV and need hospitalization.
Mild RSV infections will go away in a week or two without treatment. The CDC said people can use over-the-counter fever reducers and pain relievers to manage symptoms.
RSV is the most common cause of bronchiolitis and pneumonia in children younger than 1 year of age, although in very young infants with RSV, the only symptoms may be irritability, decreased activity and breathing difficulties.
Almost all children will have had an RSV infection by their second birthday, according to the CDC.
The CDC recommends you use one of these two tools to protect your baby from getting very sick with RSV:
- An RSV vaccine given during pregnancy
- An RSV immunization given to infants and older babies
Most infants will not need both.
Vaccines are available to protect older adults from serious RSV.
How RSV spreads
RSV can spread when:
- An infected person coughs or sneezes
- You get virus droplets from a cough or sneeze in your eyes, nose, or mouth
- You have direct contact with the virus, like kissing the face of a child with RSV
- You touch a surface that has the virus on it, like a doorknob, and then touch your face before washing your hands
RSV symptoms
The CDC said people infected with RSV usually show symptoms within four to six days of getting infected. Symptoms include:
- Runny nose
- Decrease in appetite
- Coughing
- Sneezing
- Fever
- Wheezing
The symptoms usually appear in stages and not all at once, according to the CDC.
How to relieve RSV symptoms
Steps to relieve symptoms:
- Manage fever and pain with over-the counter fever reducers and pain relievers like acetaminophen or ibuprofen. (Never give aspirin to children)
- Drink enough fluids: It is important for people with RSV infection to drink enough fluids to prevent dehydration (loss of body fluids).
- Talk to your health care provider before giving your child nonprescription cold medicines. Some medicines contain ingredients that are not good for children.
RSV can cause more severe infections
RSV can also cause more severe infections such as bronchiolitis and pneumonia.
Bronchiolitis is an inflammation of the small airways in the lung.
Pneumonia is an infection of the lungs.
How to limit the spread of RSV
Here are preventative measures to limit the spread of RSV:
- Stay home when sick
- Cover your coughs and sneezes with a tissue or your shirt sleeve, not your hands.
- Wash your hands often with soap and water for at least 20 seconds.
- Avoid touching your face with unwashed hands.
- Avoid close contact with others, such as kissing, shaking hands and sharing cups and eating utensils.
- Clean frequently touched surfaces such as doorknobs and mobile devices.
Can someone get vaccines for the flu, COVID-19 and RSV all at once?
CDC guidance states that influenza, COVID-19 and RSV vaccines can all be given at the same time to eligible people. The Health Alert Network (HAN) published a report on Sept. 5, 2023, for additional information about simultaneous administration of these vaccines.
