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What is respiratory syncytial virus (RSV)? Symptoms, causes and care.

This infection is similar to the common cold. But it can become more serious, and a new wave of vaccines can help prevent RSV associated respiratory infections.

Updated: August 20, 2024 |9 minutes to read

Written by: Lauren Arcuri

A doctor laughs with a young child as they check for RSV.

When winter rolls around, it can sometimes bring with it coughing, sneezing and wheezing that comes with seasonal illnesses. This can be caused by respiratory syncytial virus (RSV), which is a highly contagious virus that causes cold-like symptoms. However, there are vaccinations available for some people that can help protect from infections caused by RSV.1

In this article:

What is RSV?

Respiratory syncytial virus (RSV) is an infection that affects the lungs and airways. For most people, symptoms of RSV are mild and go away in about a week or two.2 But for vulnerable individuals, RSV can lead to serious illness or death.3

In the United States, RSV generally arises in the fall, peaking in late December through mid-February and ending in spring.4 And every year, it is responsible for about 60,000 to 160,000 hospitalizations of those 65 and older4 and about 58,000 to 80,000 hospitalizations for children younger than 5 years old.5

The infection is highly contagious and, among vulnerable groups, can lead to lower respiratory tract disease (LRTD).6 One example of LRTD is pneumonia, which can be life threatening in older adults. It can also worsen conditions like asthma, chronic obstructive pulmonary disease and congestive heart failure. In babies and young children whose immune systems aren’t fully formed, it can lead to respiratory problems and the need for breathing support methods.7,8

It is so common in children that “the majority of children will have been infected with RSV by the age of 2,”8 says Krupa Playforth, MD, a board-certified pediatrician at Warm Heart Pediatrics and an American Academy of Pediatrics fellow.9

Symptoms of RSV

Symptoms of RSV are like those of the common cold and may include:8

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

Symptoms usually become apparent four to six days after infection and typically appear in stages rather than all at once.8 These symptoms generally last two to eight days, according to the American Lung Association,10 but can linger up to two weeks, adds Dr. Playforth.

In very young infants, symptoms may be decreased activity, irritability and difficulty breathing.8 “Difficulty breathing often interferes with their ability to feed, so people may notice that too as well as dehydration,”8,11 Dr. Playforth says.

RSV causes and transmission

RSV is a virus that is very contagious.12 It can spread when an infected person coughs or sneezes and those virus droplets get in a person’s eyes, nose or mouth. People can also get it if they touch a surface that has RSV on it and then touch their face without washing their hands first, or if they have direct contact with the virus, such as kissing the face of someone with RSV.13

Children who attend childcare centers or have siblings who attend school or day care are also at a higher risk of RSV exposure.14

How long is RSV contagious?

People infected with RSV are usually contagious for three to eight days (about the entire time they have the virus) and can become contagious one to two days before symptoms begin.14

Some infants and people with weakened immune systems can spread RSV even after they stop showing symptoms.13

Furthermore, people can get RSV multiple times over their lifetime because the immune system doesn’t form lasting immunity to the infection.15

How is RSV diagnosed?

Though not required for mild cases of RSV, health care professionals can perform RSV testing. “There are antigen tests and molecular (or PCR) tests, which can be done via nasal swab,”16,10 says Dr. Playforth.

For severe cases that lead to hospitalization, additional methods, such as computed tomography (CT) scans or chest X-rays, may be used.16

How to manage RSV?

Most mild RSV infections resolve on their own in a week or two, so antiviral medication is not typically recommended to treat the infection.8

“Antibiotics cannot be used to treat it, so we focus on supporting the body with fluids, pain management and rest,” says Dr. Playforth.

The best ways to help relieve symptoms include:

Be sure to talk to your health care provider before caring for a child at home and before giving them any sort of medicine. And always consult your pharmacist or health care provider before taking any over-the-counter medications.

Who should get an RSV vaccine?

Vaccines are available to help prevent severe RSV in vulnerable individuals.

For those over 75 or those over 60 with an increased risk of severe RSV, there are three RSV vaccines available in the United States. It is recommended that these age groups get a single lifetime dose of an RSV vaccine after talking to their health care provider to determine if they would benefit from such an intervention. Pregnant people are also eligible to receive one of the available formulations during weeks 32 to 36 of their pregnancy. These can be given September through January.17

In September 2023, the CDC also recommended the first RSV vaccine for pregnant people to help protect their newborns from severe RSV illness.18

For babies and young children, there are two available monoclonal antibody products: nirsevimab and palivizumab. Though not vaccines, these antibodies can serve as an added barrier of defense against severe RSV infections.19,20

Nirsevimab is recommended for infants under 8 months old, who were born during or are entering their first RSV season and the mother didn’t receive the RSV vaccine during pregnancy or who were born within 14 days of vaccination. Some infants and children between 8 and 19 months who are at increased risk for severe RSV disease are eligible to receive nirsevimab shortly before the start of their second RSV season.18

Palivizumab has been available for many years and is reserved for children 24 months old or younger with certain conditions that make them more susceptible to severe RSV (it’s given once a month during RSV season and generally limited to five total doses).21,18

Learn more and explore scheduling options.

Risk factors and complications of RSV

Those who are at risk for severe RSV include:22

  • Adults ages 75 and older
  • Children who are younger than 2 years old with chronic lung or congenital heart disease23
  • Premature infants and infants under 6 months old24,25
  • Those who are frail
  • Those who have severe obesity with a body mass index (BMI) over 40
  • Those with certain kidney disorders
  • Those with chronic heart or lung disease
  • Those with diabetes mellitus with organ damage caused by diabetes
  • Those with hematologic disorders
  • Those with liver disorders
  • Those with moderately to severely compromised immune systems
  • Those with neurologic or neuromuscular conditions
  • Those living in a nursing home or long-term care facility

If you or someone you know falls into one of these categories, be sure to talk with your health care provider about RSV protection and management.

In addition to the complications previously stated (mainly hospitalization and pneumonia), RSV could cause middle ear infection (otitis media) and may result in repeat infections. It may also increase the risk of developing asthma later in life in children who experienced severe RSV.23

In those who develop bronchiolitis from RSV (which affects the lower airways of the lungs), “we also often see rapid or shallow breathing, increased work to breathe or low oxygen levels in the blood,” says Dr. Playforth. Similarly, if an RSV infection leads to worsening asthma or chronic obstructive pulmonary disease (COPD) symptoms, the person may experience an asthma attack or COPD exacerbation.26

“As with many other respiratory conditions, anyone can have a severe course,” says Dr. Playforth. “The most important thing to remember is to trust your gut as a parent. If your child seems like they are doing poorly, it is extremely important to have them evaluated by a health care provider right away.” And the same goes for yourself or a loved one in your life: If illness strikes or worsens or the risk for contracting severe RSV is high, talk to a health care provider today.

This content is for informational purposes only and is not medical advice. Consult your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.