How Long Are You Contagious After Being Sick?

Contagiousness is the time when a person can spread an illness to others. This period varies by disease. Many respiratory viruses can spread before symptoms appear.

Respiratory infections primarily spread through tiny droplets released when a person coughs, sneezes or talks. These droplets can be inhaled by others or come into contact with their nose, mouth or eyes, making it easier for a contagious illness to spread.

If your symptoms improve for 24 hours and you no longer have a fever, you are usually less contagious. However, you may still be able to spread the virus that made you sick, according to the Centers for Disease Control and Prevention (CDC). To lower this risk, keep taking precautions. Wear a mask and avoid close contact with others for five more days.

People with weakened immune systems, like the elderly and those with chronic health conditions, may stay contagious for a longer time.

Many respiratory illnesses have similar symptoms, like coughing and fatigue. However, they differ in how severe and how long they last. The flu usually has more severe symptoms, such as a high fever and body aches. The common cold causes milder symptoms, like a runny nose and a mild headache.

Children may show symptoms differently. They often have fevers more often because their immune systems are still developing. As a result, children, especially infants, may have more noticeable symptoms as their bodies fight the illness.

Knowing the symptoms of common respiratory illnesses like the cold, flu and COVID-19 can help you understand what you might be dealing with. It can help guide your treatment and help prevent spreading it to others.

Colds can happen any time of the year. Adults on average get two to three colds each year in the United States. Children often catch colds more often, according to the CDC.

Symptoms usually appear one to three days after exposure, meaning you can spread a cold before you feel sick.

Colds usually last for less than a week. People can spread the virus as long as they have symptoms. Children and babies may be contagious for a longer time.

• Runny nose or nasal congestion
• Cough
• Sneezing
• Headache
• Mild body aches
• Low-grade fever

• Stay home and rest; drink plenty of liquids.
• Practice good hand hygiene by washing your hands frequently with soap and water.
• Avoid close contact with others until symptoms subside.

Colds usually resolve on their own. Antibiotics are not effective unless a bacterial infection develops as a complication.

There is no specific test for the common cold. It is usually diagnosed based on the person’s symptoms.

Over-the-counter medicines, such as pain relievers or fever reducers, can help relieve symptoms of the common cold, flu and COVID but they won’t cure the illnesses.

People with the flu are most contagious during the first three days of being sick, according to the CDC. They can spread the virus to others as early as one day before symptoms appear and for up to seven days after getting sick.

While most people with the flu are contagious for up to a week, this period may be longer for young children or those with weakened immune systems.

Flu symptoms can range from mild to severe and typically develop suddenly.

• Fever or chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Fatigue
• Headaches
• Vomiting and diarrhea (more common in children)

• Get a flu vaccine annually, especially if you are at higher risk for complications.
• Stay home for at least 24 hours after your symptoms improve. You should be fever-free and not have taken any fever-reducing medicine.
• Cover your mouth and nose with a tissue or your elbow when you cough or sneeze.
• Wear a mask to prevent spreading the virus.
• Wash your hands frequently with soap and water.
• Improve air quality by increasing ventilation or using air purifiers.
• Talk to your healthcare provider about antiviral medicines, which can help make flu symptoms shorter and less severe.

Flu testing is typically done when symptoms are severe or for those at high risk for complications.  

People with COVID can spread the virus one to two days before they show symptoms. They can remain contagious for eight to 10 days after that, according to the CDC.

Most transmission occurs early in the infection. This is especially true one to two days before symptoms start and during the first days after they appear. This can vary based on symptom severity.

Many people with COVID have mild symptoms. However, some can become very sick. This is especially true for older adults and those with weakened immune systems or other health issues.

• Fever or chills 
• Cough 
• Shortness of breath or difficulty breathing 
• Fatigue 
• Muscle or body aches 
• Headache 
• New loss of taste or smell 
• Sore throat 
• Congestion or runny nose 
• Nausea or vomiting 
• Diarrhea

• Get tested for COVID-19.
• For self-testing, use an antigen test. A positive result means you are more contagious.
• Stay home if you test positive or show symptoms.
• Wear a mask in public, especially when social distancing is not possible.
• Wash your hands frequently with soap and water or use hand sanitizer with at least 60% alcohol.
• Cover coughs and sneezes with a tissue or your elbow.
• Regularly clean and disinfect commonly touched surfaces.
• Monitor your symptoms and seek medical advice if they worsen or if you have difficulty breathing.
• Get vaccinated to lower the risk of severe illness and transmission.

Preventing the spread of contagious diseases is important for everyone. “Good hygiene, staying home when sick and getting vaccinated for the flu and COVID are key steps,” Dr. Hadley says.

“While there is no vaccine for the common cold, you can still reduce its spread,” he adds. “Washing your hands often and avoiding close contact with others are just some of the ways. These measures and others help protect people at risk by lowering the chance of spreading an illness.”