RSV (Respiratory Syncytial Virus)

Respiratory syncytial virus at a glance

RSV (respiratory syncytial virus) is a common respiratory virus infecting all age groups, typically only causing a mild illness and generally clearing within a week.
In infants, older adults and adults with comorbidities (heart disease, asthma, etc.) or who are immunocompromised, the symptoms can be more severe and may result in hospitalization or even death.
It is contagious by contact with infected people when they cough and sneeze or through contact with objects contaminated with the virus such as bedding and surfaces.
Early symptoms are similar to a common cold and include fever, congestion, runny nose, cough and sore throat; more severe symptoms indicate the need for medical or emergency care.
There is no cure for RSV and treatments including home care and medical care seek to manage symptoms, preventing progression to severe cases.
ID Care specialists assess patients, diagnose the virus and guide treatment, including during hospitalization.

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What is RSV?

RSV (respiratory syncytial virus) is a common virus that causes respiratory tract infection in all age groups. In healthy adults and older children, RSV typically causes a mild illness similar to that of a common cold. However, the symptoms can be more severe in infants under six months old, older adults, and adults with comorbidities, such as heart disease, obesity, diabetes and asthma, or who are immunocompromised.

This virus is prevalent in the United States and can progress to life-threatening stages. The Centers for Disease Control and Prevention estimate the following instances of RSV from October 2024 to May 2025:

Outpatient doctor visits: 3.6 million-6.5 million.
Hospitalizations: 190,000-350,000.
Deaths: 10,000-23,000.

How does this respiratory virus spread?

Person-to-person transmission of RSV occurs through contact with droplets from the nose and throat of infected people when they cough and sneeze. RSV can also spread through contact with objects contaminated with the virus such as doorknobs, toys or linen.

It can take four to six days from exposure until the onset of symptoms. The illness itself lasts three to seven days, and infected people are most contagious during this time. The peak season for RSV infection in the U.S. is fall through spring.

Because people do not form long-lasting immunity to RSV, they can become infected repeatedly over their lifetime. Multiple infections during peak RSV season are also possible.

RSV in adults

Most adults have likely had RSV, but were unaware of it without a lab test to confirm diagnosis.

Adults at risk for the virus becoming severe or life threatening include:

Older adults suffering from lung or heart disease, asthma, congestive heart failure and chronic obstructive pulmonary disease (COPD).
People with immunodeficiency, such as organ transplant recipients, patients receiving chemotherapy and those living with HIV.

RSV in babies and children

RSV typically causes a mild illness in babies and children. This respiratory virus is so common that almost all children will have been infected with the virus by age 2. Most children contract RSV before that age simply because of contact with other children.

Infants or young children at risk for serious cases of RSV include those:

Born prematurely.
With congenital heart or lung disease.
With weakened immune systems.
Who have neuromuscular disorders.

According to the American College of Obstetricians and Gynecologists, RSV infection is the most common reason for infant hospitalization in the U.S.

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RSV fast facts

What is RSV?

RSV (respiratory syncytial virus) is a common virus that generally causes mild illness but can also progress to severe cases and even death, with 10,000-30,000 deaths per year in the U.S.

What is RSV in adults?

Most adults have had RSV without even knowing it, but it is a serious problem for older adults who are immunocompromised and those with chronic conditions such as heart disease, diabetes, asthma and others.

What is RSV in babies?

RSV is the leading cause of infant hospitalization in the U.S. The disease is very dangerous for babies and children at high risk, which includes those born prematurely, those with congenital heart or lung disease, neuromuscular disorders or weak immune systems.

How is RSV spread?

This contagious virus spreads through contact with infected people who expel droplets containing the virus when they cough and sneeze. It also spreads through contact with objects contaminated with the virus such as bedding and counter surfaces.

What are the first signs of RSV?

First symptoms are similar to a common cold (which is why many people don’t know they have RSV) and include congestion, cough, fever, sore throat, runny nose and loss of appetite.

RSV symptoms

Early signs of RSV infection are similar to mild cold symptoms. The symptoms listed below generally do not occur all at once but usually appear in stages:

Fever.
Congestion.
Runny nose.
Cough and sore throat.
Decrease in appetite.

Very young infants may be irritable, fatigued and have breathing difficulties. Normally these symptoms will clear up on their own in a few days.

A barking or wheezing cough can indicate a more serious case of RSV. In these instances, the virus has spread to the lower respiratory tract, which can lead to bronchiolitis (inflammation of the small airways of the lungs) or pneumonia.

Infants with severe RSV may experience short, shallow and rapid breathing characterized by chest retractions (the skin between or below the ribs visibly sinking in during inhalations) and nasal flaring at an increased rate.

Respiratory syncytial virus diagnosis

In mild cases of RSV, symptoms are similar to the common cold. In these instances, which include most cases, medical providers may not conduct testing to make a diagnosis of the infection.

However, if infection is suspected in individuals at increased risk for severe or life-threatening RSV based on medical history and time of year, the infectious disease specialists at ID Care will provide a thorough physical examination of symptoms. This may include running laboratory tests – a mouth swab or a blood test – to confirm a diagnosis.

RSV treatment

There is no cure for this respiratory virus, and treatment seeks to manage symptoms, most often at home. Mild RSV infections will go away within a week or two without treatment. In most cases we do not recommend antiviral drugs.

At home care

Over-the-counter products such as pain relievers, fever reducers and nasal saline drops can be used to manage symptoms. Drinking plenty of fluids to prevent dehydration is an important part of home care as well.

ID Care physicians can monitor for severe RSV cases, which may require hospitalization. Signs of virus severity indicating the need to seek medical help include:

Shallow, rapid breathing.
Struggling to breathe.
Irritability.
Unusual tiredness.

Seek emergency care for adults or children if these signs are present:

Severe trouble breathing with choking or gasping for air.
Signs of low oxygen: skin, lips or fingernails that looks bluish or grayish.
Unresponsiveness or limpness.
High fever – for infants two months or younger, a fever of 100.4° or higher accompanied by the above symptoms.

Hospitalization care

Our specialists can determine if hospitalization is required. This can involve stronger measures to control symptoms such as increased surveillance, IV fluids, humidified oxygen and in rare instances mechanical ventilation. If pneumonia results from lower respiratory tract issues, we may prescribe antibiotics.

Respiratory syncytial virus in New Jersey

The New Jersey Department of Health (NJDH) tracks respiratory viruses in the state. In its Respiratory Illness Surveillance report of November 22, 2025, (most recent at time of publication), NJDH reports that emergency room visits due to flu or RSV remained low.

The majority of hospitalizations for RSV have been for newborns to 4 years old and people 65 and older. Positive test results for RSV had also been rising. Past data shows that from October-December 2024, the most cases of RSV emergency room visits resulting in hospital admissions occurred in the newborn-age 4 group.

Respiratory syncytial virus prevention

There are simple, effective steps you can take to help prevent the spread of RSV. ID Care and NJDH recommend the following:

Avoid close contact with sick people.
Stay home when you are sick.
Avoid sharing cups, bottles or toys that may have been contaminated with the virus.
Wash your hands often with soap and water for at least 20 seconds.
Clean and disinfect frequently touched objects and surfaces such as phones and doorknobs.
If you have cold-like symptoms, cover your coughs and sneezes with a tissue or your upper shirt sleeve, not your hands.
Get vaccinated if appropriate.

Related Reading: Advancements in prevention

RSV vaccine

Most adults are not at increased risk for severe cases of RSV, so we do not recommend that they get the respiratory syncytial virus vaccine, which is Abrysvo by Pfizer. The RSV vaccine is appropriate to protect adults older than 50.

ID Care and the CDC recommend the vaccine for adults over 75 and for those aged 50-74 who are at increased risk for severe cases of RSV (see respiratory syncytial virus in adults above).

The vaccine is appropriate for pregnant women between weeks 32 and 36 of pregnancy. The RSV vaccine passes antibodies to the fetus, protecting the child for up to 6 months after birth.

Nirsevimab, palivizumab or clesrovimab antibodies for babies

Nirsevimab, palivizumab and clesrovimab are not respiratory syncytial virus vaccines, but they provide protection against RSV for infants and young children who are at risk from the virus. Infants who should receive one of these antibodies are those: