rsv

Respiratory syncytial virus, or RSV, is a common respiratory virus. It usually causes mild, cold-like symptoms. But it can cause serious lung infections, especially in infants, older adults, and people with serious medical problems.

RSV spreads from person to person through:

• The air by coughing and sneezing
• Direct contact, such as kissing the face of a child who has RSV
• Touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands

People who have an RSV infection are usually contagious for 3 to 8 days. But sometimes infants and people with weakened immune systems can continue to spread the virus for as long as 4 weeks.

RSV can affect people of all ages. But it is very common in small children; nearly all children become infected with RSV by age 2. In the United States, RSV infections usually occur during RSV season, which is usually fall through spring.

Certain people are at higher risk of having a severe RSV infection:

• Infants
• Older adults, especially those ages 65 and older
• People with chronic medical conditions such as heart or lung disease
• People with weakened immune systems

The symptoms of RSV infection usually start about 4 to 6 days after infection. They include:

• Runny nose
• Decrease in appetite
• Cough
• Sneezing
• Fever
• Wheezing

These symptoms usually appear in stages instead of all at once. In very young infants, the only symptoms may be irritability, decreased activity, and trouble breathing.

RSV can also cause more severe infections, especially in people at high risk. These infections include bronchiolitis, an inflammation of the small airways in the lung, and pneumonia, an infection of the lungs.

Your health care provider may use many tools to make a diagnosis:

• A medical history, including asking about symptoms.
• A physical exam.
• A lab test of nasal fluid or another respiratory specimen to check for RSV. This is usually done for people with severe infection.
• Tests to check for complications in people with severe infection. The tests may include a chest x-ray and blood and urine tests.

There is no specific treatment for RSV infection. Most infections go away on their own in a week or two. Over-the-counter pain relievers can help with the fever and pain. However, do not give aspirin to children. And do not give cough medicine to children under four. It is also important to get enough fluids to prevent dehydration.

Some people with severe infection may need to be hospitalized. There, they might get oxygen, a breathing tube, or a ventilator.

There are some vaccines to protect against RVS illness. Two of them are for people ages 60 and older. If you are in this age group, talk to your provider about whether an RSV vaccine would be right for you.

If you are pregnant, there is a vaccine that is available to give between 32 and 36 weeks of pregnancy. It helps protect their newborn babies from RSV illness for the first 6 months of life.

There are two medicines to help prevent severe RSV illness in babies and young children. These medicines may help prevent severe RSV illness, but they can't cure or treat children who already have RSV. And they cannot prevent an RSV infection. Both medicines are given by injections (shots).

One medicine is given to infants who are younger than 8 months during their first RSV season. This includes infants who are born during RSV season. This medicine may also be given to some children between the ages of 8 and 19 months who are at high risk for severe RSV illness. For example, they might be at high risk because they:

• Were born prematurely
• Have congenital heart disease
• Have chronic lung disease
• Have a weakened immune system

The other medicine is given monthly during RSV season. It is for children under 24 months of age who are at high risk for severe RSV illness.

There are also some steps you can take to lower your risk of getting or spreading an RSV infection, including:

• Washing your hands often with soap and water for at least 20 seconds
• Avoiding touching your face, nose, or mouth with unwashed hands
• Avoiding close contact, such as kissing, shaking hands, and sharing cups and eating utensils, with others if you are sick or they are sick
• Cleaning and disinfecting surfaces that you frequently touch
• Covering coughs and sneezes with a tissue. Then throw away the tissue and wash your hands
• Staying home when sick

Centers for Disease Control and Prevention

The common cold is a mild infection of your upper respiratory tract (which includes your nose and throat). Colds are probably the most common illness. Adults have an average of 2-3 colds per year, and children have even more. Colds are more common in the winter and spring, but you can get them at any time.

More than 200 different viruses can cause a cold, but rhinoviruses are the most common type. The viruses that cause colds are very contagious. They can spread from person to person through the air and close personal contact. You can also get infected when you touch something that has the virus on it and then touch your eyes, mouth, or nose. For example, you could get a cold after you shake hands with someone who has a cold or touch a doorknob that has the germs on it, and then touch your face.

The symptoms of a common cold usually include:

• Sneezing
• Stuffy nose (congestion)
• Runny nose
• Sore throat
• Coughing
• Headache

The symptoms usually start a few days after you become infected with the virus. Some symptoms can last for 10-14 days.

There is no cure for the common cold. But there are treatments that can make you feel better while you wait for the cold to go away on its own:

• Getting lots of rest.
• Drinking plenty of fluids.
• Using a clean humidifier or cool mist vaporizer.
• Gargling with warm salt water.
• Using saline nose drops or sprays.
• Taking over-the-counter pain or cold and cough medicines. But you need to be careful with certain medicines:
  • Children and teens should not take aspirin.
  • Some cold and cough medicines contain ingredients that are not recommended for children. Talk with your child's health care provider before giving your child any cold and cough medicines.
  • Some cold and cough medicines contain pain relievers. If you also take a separate pain reliever with these medicines, you could be getting a dangerous amount of the pain reliever. Read the labels on the medicines and follow the instructions carefully. If you have questions, ask your provider or a pharmacist.

Antibiotics will not help with a cold. Antibiotics help with bacterial infections, not with viral infections such as colds.

Most people who have a cold will feel better after a week or two. However, some people who get a cold may develop other illnesses, such as bronchitis or pneumonia. This is more common in people with weakened immune systems, asthma, or other respiratory conditions. Contact your provider if you or your child have symptoms that concern you, such as:

• Trouble breathing or fast breathing
• Dehydration
• Fever that lasts longer than 4 days
• Symptoms that last more than 10 days without improvement
• Symptoms, such as fever or cough, that improve but then return or worsen
• Worsening of chronic medical conditions

There is no vaccine to protect against the common cold. But you may be able to reduce your risk of getting or spreading a cold by:

• Washing your hands often with soap and water for at least 20 seconds.
• Avoiding touching your face, nose, or mouth with unwashed hands.
• Avoiding close contact, such as kissing, shaking hands, and sharing cups and eating utensils, with others if you are sick or they are sick.
• Cleaning and disinfecting surfaces that you frequently touch.
• Covering coughs and sneezes with a tissue. Then throw away the tissue and wash your hands.
• Staying home when sick.

Centers for Disease Control and Prevention

COVID-19 (coronavirus disease 2019) is an illness caused by a virus. This virus is a coronavirus called SARS-CoV-2. It spreads when a person who has the infection breathes out droplets and very small particles that contain the virus. On this page, you'll find links to resources on important issues such as symptoms, risks, and how you can protect yourself and your family.

We also have pages on:

• COVID-19 testing
• COVID-19 vaccines
• Post-COVID conditions (long COVID)

COVID-19 (coronavirus disease 2019) is an illness caused by a virus. This virus is a coronavirus called SARS-CoV-2. In the United States, there are several vaccines that are effective at protecting people from getting seriously ill, being hospitalized, and dying from COVID-19. These vaccines are being used under Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA). This means that the vaccines have met the FDA's scientific standards for safety, effectiveness, and manufacturing quality that are needed to support authorization.

This page includes details about the vaccines and the vaccination program, including where you can find a vaccine.

Centers for Disease Control and Prevention

The flu, also called influenza, is a respiratory infection caused by viruses. Each year, millions of Americans get sick with the flu. Sometimes it causes mild illness. But it can also be serious or even deadly, especially for people over 65, newborn babies, and people with certain chronic illnesses.

The flu is caused by flu viruses that spread from person to person. When someone with the flu coughs, sneezes, or talks, they spray tiny droplets. These droplets can land in the mouths or noses of people who are nearby. Less often, a person may get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose, or possibly their eyes.

Symptoms of the flu come on suddenly and may include:

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue (tiredness)

Some people may also have vomiting and diarrhea. This is more common in children.

Sometimes people have trouble figuring out whether they have a cold or the flu. There are differences between them:

Sometimes people say that they have a "flu" when they really have something else. For example, "stomach flu" isn't the flu; it's gastroenteritis.

Some people who get the flu will develop complications. Some of these complications can be serious or even life-threatening. They include:

• Bronchitis
• Ear infection
• Sinus infection
• Pneumonia
• Inflammation of the heart (myocarditis), brain (encephalitis), or muscle tissues (myositis, rhabdomyolysis)

The flu also can make chronic health problems worse. For example, people with asthma may have asthma attacks while they have flu.

Certain people are more likely to have complications from the flu, including:

• Adults 65 and older
• Pregnant women
• Children younger than 5
• People with certain chronic health conditions, such as asthma, diabetes, and heart disease

To diagnose the flu, health care providers will first do a medical history and ask about your symptoms. There are several tests for the flu. For the tests, your provider will swipe the inside of your nose or the back of your throat with a swab. Then the swab will be tested for the flu virus.

Some tests are quick and give results in 15-20 minutes. But these tests are not as accurate as other flu tests. These other tests can give you the results in one hour or several hours.

Most people with the flu recover on their own without medical care. People with mild cases of the flu should stay home and avoid contact with others, except to get medical care.

But if you have symptoms of flu and are in a high risk group or are very sick or worried about your illness, contact your health care provider. You might need antiviral medicines to treat your flu. Antiviral medicines can make the illness milder and shorten the time you are sick. They also can prevent serious flu complications. They usually work best when you start taking them within 2 days of getting sick.

The best way to prevent the flu is to get a flu vaccine every year. But it's also important to have good health habits like covering your cough and washing your hands often. This can help stop the spread of germs and prevent the flu.

Centers for Disease Control and Prevention

The flu (influenza) is a respiratory infection. It is caused by influenza viruses that infect your nose, throat, and lungs. These viruses can spread from person to person.

Most people with the flu get better on their own, without medical care. But for some people, the flu is serious. It can cause complications and sometimes even death. People who are 65 and older, under age 5, pregnant, or have certain health conditions are at higher risk of flu complications.

Getting vaccinated against the flu each year is best way to lower your risk of the flu and its complications.

There are many reasons to get a flu shot each year:

• It may keep you from getting sick with the flu.
• If you do get the flu, it may be less severe. You may also be less likely to have complications or need to be hospitalized with the flu.
• If you have certain chronic health conditions, getting a flu shot may help prevent the flu from making your condition worse. For example, if you have COPD or diabetes, the flu can worsen your condition so much that you might need to be hospitalized. Getting a flu shot can lower this risk.
• Getting the vaccine during pregnancy not only helps protect you from the flu during and after pregnancy. It also helps protect your baby from flu during their first few months of life.
• It has been shown to lower the risk of severe life-threatening flu in children.
• It may also protect the people around you, including those who are at higher risk of complications.

The flu vaccine causes your immune system to make antibodies about two weeks after you get the shot. These antibodies provide protection against infection with the flu viruses that are in the vaccine.

The U.S Centers for Disease Control and Prevention (CDC) recommends annual flu shots for everyone 6 months and older, with a few rare exceptions.

Flu shots are especially important for people who are at high risk of developing serious complications from the flu.

There are different types of flu vaccines. There are injectable vaccines (shots) and nasal spray vaccines. There are also some vaccines especially for people 65 and older. Ask your health care provider which one is right for you.

There are some people who should not get a flu shot:

• Children younger than 6 months of age.
• Have severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine. This might include gelatin, antibiotics, or other ingredients.

Some people need to talk to their provider before they get a flu shot. They include people who:

• Have an allergy to any of the ingredients in the vaccine.
• Have ever had Guillain-Barre syndrome(GBS). Some people with a history of GBS should not get a flu vaccine.

If you are moderately or severely ill, you usually need to wait until you recover before getting a flu shot.

You need to get a flu shot every year because:

• Your immune protection from the vaccine declines over time. You need to get the shot every year to boost that protection.
• Flu viruses are constantly changing, so every year, the flu vaccine is updated. The flu vaccine will include protection against the viruses that will most likely be common during the upcoming flu season.

For most people who need only one dose of the flu vaccine for the season, September and October are usually good times to get it. It's best to be vaccinated by the end of October.

Some children need two doses of the flu vaccine. They should get their first dose as soon as the vaccine is available. They need to get the second dose at least four weeks after the first.

If you are pregnant, talk to your provider about when to get the vaccine. When you should get it can vary, based on how far along you are in your pregnancy.

Flu vaccines have been shown to be safe. But like any medical product, they can cause side effects. If you have any side effects, they are usually mild and go away on their own within a few days. Common side effects include:

• Soreness, redness, and/or swelling from the shot
• Headache
• Fever
• Nausea
• Muscle aches

The flu shot, like other injections, can occasionally cause fainting. In rare cases, some people have a serious allergic reaction.

Centers for Disease Control and Prevention

Pneumonia is an infection in one or both of your lungs. It causes the air sacs of your lungs to fill up with fluid or pus. Pneumonia can range from mild to severe, depending on what caused it, your age, and your overall health.

Bacterial, viral, and fungal infections can cause pneumonia.

Bacteria are the most common cause. Bacterial pneumonia can occur on its own. It can also develop after you've had certain viral infections such as a cold or the flu. Several different types of bacteria can cause pneumonia, including:

• Streptococcus pneumoniae
• Legionella pneumophila; this type of pneumonia is often called Legionnaires' disease
• Mycoplasma pneumoniae
• Chlamydia pneumoniae
• Haemophilus influenzae type b (Hib)

Viruses that infect the respiratory tract may cause pneumonia. Viral pneumonia is often mild and goes away on its own within a few weeks. But sometimes it is serious enough that you need to get treatment in a hospital. If you have viral pneumonia, you are at risk of also getting bacterial pneumonia. The different viruses that can cause pneumonia include:

• Respiratory syncytial virus (RSV)
• Some common cold and flu viruses
• SARS-CoV-2, the virus that causes COVID-19

Fungal pneumonia is more common in people who have chronic health problems or weakened immune systems. Some of the types include:

• Pneumocystis pneumonia"/> (PCP)
• Valley fever (Coccidioidomycosis)
• Histoplasmosis
• Cryptococcal pneumonia

Aspiration can also cause pneumonia. It can happen when you aspirate (accidentally breathe in) food or fluid into the lungs. If you are not able to cough out the food or fluid, it may cause an infection.

Anyone can develop pneumonia, but certain factors can increase your risk:

• Age; the risk is higher for children who are age 2 and under and adults age 65 and older.
• Exposure to certain chemicals, pollutants, or toxic fumes.
• Lifestyle habits, such as smoking, heavy alcohol use, and malnourishment.
• Being in a hospital, especially if you are in the ICU. Being sedated and/or on a ventilator raises the risk even more.
• Having a lung disease.
• Having a weakened immune system.
• Have trouble coughing or swallowing, from a stroke or other condition.
• Recently having been sick with a cold or the flu.
• Other chronic (long-lasting) health conditions, including diabetes, heart failure, sickle cell disease, liver disease, and kidney disease.

The symptoms of pneumonia can range from mild to severe and include:

• Fever
• Chills
• Cough, usually with phlegm (a type of thick mucus made in your lungs)
• Shortness of breath
• Chest pain when you breathe or cough
• Nausea and/or vomiting
• Diarrhea

The symptoms can vary for different groups. Newborns and infants may not show any signs of the infection. Others may vomit and have a fever and cough. They might seem sick, with no energy, or be restless.

Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower-than-normal temperature. Older adults who have pneumonia sometimes may feel weak or suddenly get confused.

Sometimes pneumonia can cause serious complications such as:

• Bacteremia, which happens when the bacteria move into the bloodstream. It is serious and can lead to septic shock.
• Lung abscesses, which are collections of pus in cavities of the lungs.
• Pleural disorders, which are conditions that affect the pleura. The pleura is the tissue that covers the outside of the lungs and lines the inside of your chest cavity.
• Kidney failure.
• Respiratory failure.

Sometimes pneumonia can be hard to diagnose. This is because it can cause some of the same symptoms as a cold or the flu. It may take time for you to realize that you have a more serious condition.

To find out if you have pneumonia, your health care provider:

• Will take your medical history, which includes asking about your symptoms
• Will do a physical exam, which includes listening to your lungs with a stethoscope
• May order various tests, such as:
  • A chest x-ray
  • Blood tests such as a complete blood count (CBC) to see if your immune system is actively fighting an infection
  • A blood culture to find out whether you have a bacterial infection that has spread to your bloodstream

If you are in the hospital, have serious symptoms, are older, or have other health problems, you may also have more tests, such as:

• Sputum test, which checks for bacteria in a sample of your sputum (mucus that is brought up from the lungs by coughing).
• Chest CT scan to see how much of your lungs are affected. It may also show if you have complications such as lung abscesses or pleural effusions (a buildup of fluid in the pleural space).
• Pleural fluid culture, which checks for bacteria in a fluid sample that was taken from the pleural space.
• Pulse oximetry or blood oxygen level test, to check how much oxygen is in your blood.
• Bronchoscopy, a procedure used to look inside your lungs' airways.

Treatment for pneumonia depends on the type of pneumonia, which germ is causing it, and how severe it is:

• Antibiotics treat bacterial pneumonia and some types of fungal pneumonia. They do not work for viral pneumonia.
• In some cases, your provider may prescribe antiviral medicines for viral pneumonia.
• Antifungal medicines treat other types of fungal pneumonia.

You may need to be treated in a hospital if your symptoms are severe or if you are at risk for complications. While there, you may get additional treatments. For example, if your blood oxygen level is low, you may receive oxygen therapy.

It may take time to recover from pneumonia. Some people feel better within a week. For other people, it can take a month or more.

Vaccines can help prevent pneumonia caused by pneumococcal bacteria or the flu virus. Washing your hands often, not smoking, and having a healthy lifestyle may also help prevent pneumonia.

NIH: National Heart, Lung, and Blood Institute

Vaccines are injections (shots), liquids, pills, or nasal sprays that you take to teach your body's immune system to recognize and defend against harmful germs. For example, there are vaccines to protect against diseases caused by:

• Viruses, like the ones that cause the flu and COVID-19
• Bacteria, including tetanus, diphtheria, and pertussis

There are several types of vaccines:

• Live-attenuated vaccines use a weakened form of the germ.
• Inactivated vaccines use a killed version of the germ.
• Subunit, recombinant, polysaccharide, and conjugate vaccines use only specific pieces of the germ, such as its protein, sugar, or casing.
• Toxoid vaccines use a toxin (harmful product) made by the germ.
• mRNA vaccines use messenger RNA, which gives your cells instructions for how to make a protein (or piece of a protein) of the germ.
• Viral vector vaccines use genetic material, which gives your cells instructions for making a protein of the germ. These vaccines also contain a different, harmless virus that helps get the genetic material into your cells.

These vaccines may work in different ways, but they all spark an immune response. The immune response is the way your body defends itself against substances it sees as foreign or harmful. These substances include germs that can cause disease.

There are different steps in the immune response:

• When a germ invades, your body sees it as foreign.
• Your immune system helps your body fight off the germ.
• Your immune system also remembers the germ. It will attack the germ if it ever invades again. This "memory" protects you against the disease that the germ causes. This type of protection is called immunity.

Immunization is the process of becoming protected against a disease. But it can also mean the same thing as vaccination, which is getting a vaccine to become protected against a disease.

Vaccines are important because they protect you against many diseases. These diseases can be very serious. So getting immunity from a vaccine is safer than getting immunity by being sick with the disease.

For a few vaccines, getting vaccinated can actually give you a better immune response than getting the disease would.

But vaccines don't just protect you. They also protect the people around you through community immunity.

Community immunity, or herd immunity, is the idea that vaccines can help keep communities healthy.

Normally, germs can travel quickly through a community and make a lot of people sick. If enough people get sick, it can lead to an outbreak. But when enough people are vaccinated against a certain disease, it's harder for that disease to spread to others. This type of protection means that the entire community is less likely to get the disease.

Community immunity is especially important for people who can't get certain vaccines. For example, they may not be able to get a vaccine because they have weakened immune systems. Others may be allergic to certain vaccine ingredients. And newborn babies are too young to get some vaccines. Community immunity can help to protect them all.

Vaccines are safe. They must go through extensive safety testing and evaluation before they are approved in the United States.

A vaccine, or immunization, schedule lists which vaccines are recommended for different groups of people. It includes who should get the vaccines, how many doses they need, and when they should get them. In the United States, the Centers for Disease Control and Prevention (CDC) publishes the vaccine schedule.

It's important for both children and adults to get their vaccines according to the schedule. Following the schedule allows them to get protection from the diseases at exactly the right time.

Viruses are very tiny germs. They are made of genetic material (either DNA or RNA) inside of a protein coating. There are a huge number of viruses on earth. Only a small number of them can infect humans. Those viruses can infect our cells, which may cause disease. Some of the diseases that viruses can cause include the common cold, the flu, COVID-19, and HIV.

Viruses can be spread in different ways:

• Through droplets and particles that are breathed out by someone who has the infection. You might breathe in the droplets or particles, or they could land on your mouth, nose, or eyes.
• By touching surfaces or objects that have the virus on them and then touching your mouth, nose, or eyes.
• From the pregnant parent to the baby during pregnancy.
• Through contaminated food or water.
• By being bitten by an infected insect or animal.
• Through sexual contact (usually vaginal, anal and oral sex) with someone who has the infection.

Viruses are like hijackers. They invade living, normal cells. They then use those cells to multiply (make copies of themselves). This process is also called replication. The process can kill, damage, or change the infected cells. Sometimes this can make you sick. The symptoms can range from mild to very severe. Other times, your immune system may be able to fight it off and you may not have any symptoms.

Each different virus usually only infects one type of cell in your body. For example, hepatitis viruses affect the cells in the liver. HIV infects a certain type of immune system cell.

For most viral infections, treatments can only help with symptoms while you wait for your immune system to fight off the virus. There are antiviral medicines to treat some viral infections. Antibiotics do not work for viral infections.

Vaccines can help prevent you from getting many viral diseases. You may be able to prevent some viral infections by:

• Proper hand washing.
• Paying attention to food safety.
• Cleaning surfaces that may be infected with germs.
• Avoiding contact with wild animals.
• Preventing insect bites by using insect repellent when you go outdoors. If you travel to an area that has a high risk of diseases from insect bites, also wear long pants, shirts, and socks.
• Practicing safe sex (using a condom every time you have anal, vaginal, or oral sex).
• Avoiding close contact with people who are sick.

Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It causes a cough that often brings up mucus. It can also cause shortness of breath, wheezing, a low fever, and chest tightness. There are two main types of bronchitis: acute and chronic.

Most cases of acute bronchitis get better within several days. But your cough can last for several weeks after the infection is gone.

The same viruses that cause colds and the flu often cause acute bronchitis. These viruses spread through the air when people cough, or though physical contact (for example, on unwashed hands). Being exposed to tobacco smoke, air pollution, dusts, vapors, and fumes can also cause acute bronchitis. Less often, bacteria can also cause acute bronchitis.

To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests.

Treatments include rest, fluids, and aspirin (for adults) or acetaminophen to treat fever. A humidifier or steam can also help. You may need inhaled medicine to open your airways if you are wheezing. Antibiotics won't help if the cause is viral. You may get antibiotics if the cause is bacterial.

NIH: National Heart, Lung, and Blood Institute