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

When winter rolls around, it can sometimes bring with it coughing, sneezing and wheezing that comes with seasonal illnesses. But this year, there may be relief for some. The U.S. Food and Drug Administration recently approved vaccines for one highly contagious seasonal virus that ordinarily causes cold-like symptoms: respiratory syncytial virus (RSV).^1,2

In this article:

• What is RSV?
• Symptoms of RSV
• RSV causes and transmission
• How long is RSV contagious?
• How is RSV diagnosed?
• How to manage RSV
• Who should get an RSV vaccine?
• Risk factors and complications

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.³ But for vulnerable individuals, RSV can lead to serious illness or death.⁴

In the United States, RSV generally arises in the fall, peaking in late December through mid-February.⁵ And every year, it is responsible for about 60,000 to 160,000 hospitalizations of those 65 and older⁶ and about 58,000 to 80,000 hospitalizations for children younger than 5 years old.⁷

The infection is highly contagious and, among vulnerable groups, can lead to lower respiratory tract disease (LRTD).⁸ 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.^9,10

It is so common in children that “the majority of children will have been infected with RSV by the age of 2,”¹¹ says Krupa Playforth, MD, a board-certified pediatrician at Warm Heart Pediatrics and American Academy of Pediatrics fellow.¹²

Symptoms of RSV

Symptoms of RSV are like those of the common cold and may include:¹³

• 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.¹⁴ These symptoms generally last two to eight days, according to the American Lung Association,¹⁵ but can linger up to two weeks, adds Dr. Playforth.

In very young infants, symptoms may be decreased activity, irritability and difficulty breathing.¹⁶ “Difficulty breathing often interferes with their ability to feed, so people may notice that too as well as dehydration,”^17,18 Dr. Playforth says.

RSV causes and transmission

RSV is a virus that is very contagious.¹⁹ 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.²⁰

Children who attend childcare centers or have siblings who attend school or day care are also at a higher risk of RSV exposure.²¹

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.²²

Some infants and people with weakened immune systems can spread RSV even after they stop showing symptoms.²³

Furthermore, people can get RSV multiple times over their lifetime because the immune system doesn’t form lasting immunity to the infection.²⁴

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,”^25,26 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.²⁷

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.²⁸

“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:

• Manage pain and fever with over-the-counter pain relievers like acetaminophen or ibuprofen.²⁹
• Ease cough and congestion with cough, cold and flu medicines.
• Drink plenty of fluids to prevent dehydration.³⁰

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 or monoclonal antibody?

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

For those 60 and over, there are two RSV vaccines available in the United States. It is recommended that this age group get a single dose of an RSV vaccine after talking to their health care provider to determine if they would benefit from such an intervention.³¹

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.^32,33

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.³⁴

Palivizumab has been available for many years³⁵ 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).³⁶

In September 2023, the CDC also recommended the first RSV vaccine for pregnant people to help protect their newborns from severe RSV illness.³⁷

Learn more and explore scheduling options.

Risk factors and complications of RSV

High-risk individuals include:³⁸

• Children who were born prematurely and have chronic lung disease
• Children with cystic fibrosis who have severe disease
• Older adults
• Premature infants and infants under 6 months old^39,40
• Those with chronic heart or lung disease
• Those  with a compromised immune system
• Those with diabetes mellitus
• Those with hematologic disorders
• Those with kidney disorders
• Those with liver disorders
• Those with moderate to severe compromised immunity
• 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.⁴¹

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.⁴²

“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.