What Is RSV?

RSV is a contagious virus that infects the nose, throat, airways and lungs.
Nearly everyone encounters it during childhood, and infection does not create
permanent immunity. That means a person can catch RSV more than once throughout
life. Reinfections are often mild, but they can still become serious in
vulnerable people.

In the United States, RSV generally circulates most actively from fall through
spring, although timing varies by region and from one year to another. It often
appears alongside influenza, COVID-19 and other seasonal respiratory viruses,
creating a crowded waiting room of microscopic troublemakers.

Why RSV Can Be More Serious in Babies

A baby’s airways are much narrower than an adult’s. When RSV causes swelling
and mucus in those tiny passages, airflow can become restricted quickly. The
virus is a leading cause of bronchiolitis, which is inflammation of the smallest
airways in the lungs, and it can also cause pneumonia.

Very young infants do not always develop the familiar combination of cough and
fever. Their first signs may be poor feeding, irritability, reduced activity,
breathing difficulty or apnea, meaning brief pauses in breathing.

Common RSV Symptoms

Symptoms usually begin about four to six days after exposure. They frequently
appear in stages instead of arriving all at once. A runny nose may show up
first, followed later by coughing, wheezing or a reduced appetite.

Mild RSV Symptoms

• Runny or congested nose
• Sneezing
• Mild to moderate cough
• Low-grade fever
• Reduced appetite
• Fatigue or lower energy
• Sore throat in some older children and adults
• Headache or mild body discomfort

Most healthy children and adults recover within one or two weeks. The cough can
occasionally linger after the fever and congestion improve, as though it did
not receive the memo that the illness was supposed to leave.

Symptoms of RSV in Infants and Young Children

Babies cannot explain that their chest feels tight or their nose is clogged, so
caregivers must watch their behavior and breathing. Signs may include:

• Feeding more slowly or refusing breast milk or formula
• Fewer wet diapers
• Irritability or unusual fussiness
• Reduced activity or difficulty waking
• Rapid, shallow breathing
• Wheezing or grunting
• Flaring nostrils
• Head bobbing while breathing
• Skin pulling inward between or beneath the ribs
• Pauses in breathing

RSV Symptoms in Adults

Healthy adults usually experience cold-like illness. Older adults and people
with chronic heart or lung disease may develop shortness of breath, worsening
wheezing, severe fatigue or a flare of conditions such as asthma, chronic
obstructive pulmonary disease or congestive heart failure.

Severe adult RSV may lead to pneumonia, low blood oxygen or hospitalization.
Sudden confusion, chest pressure, bluish or gray skin, inability to remain awake
or significant difficulty breathing requires urgent medical attention.

What Causes RSV and How Does It Spread?

RSV infection is caused by exposure to respiratory syncytial virus. An infected
person releases virus-containing droplets when coughing, sneezing or talking.
Those droplets may reach another person’s eyes, nose or mouth directly or land
on nearby objects.

Transmission can occur through close personal contact, including touching,
kissing or caring for an infected child. It can also occur after touching a
contaminated toy, countertop, crib rail, phone or doorknob and then touching
the face. Childcare centers and crowded households provide RSV with an
especially efficient travel network.

People are generally contagious for three to eight days and may spread the
virus one or two days before symptoms begin. Some infants and people with
weakened immune systems can remain contagious for several weeks.

Who Is Most Likely to Develop Severe RSV?

Groups at increased risk include:

• Infants younger than 6 months
• Babies born prematurely
• Children younger than 2 with chronic lung or congenital heart disease
• Children with neuromuscular disorders that make clearing mucus difficult
• Children or adults with weakened immune systems
• Adults age 75 and older
• Adults ages 50 to 74 with conditions that increase RSV risk
• People with chronic heart or lung disease
• Residents of nursing homes and long-term care facilities

Risk is not a guarantee that an infection will become severe. It does mean that
symptoms deserve closer monitoring and earlier communication with a healthcare
professional.

How RSV Is Diagnosed

A clinician may diagnose a mild case from symptoms, the physical examination
and the amount of RSV circulating locally. Testing is more likely when symptoms
are moderate or severe, when the patient belongs to a high-risk group or when
knowing the cause could change isolation or treatment decisions.

RSV tests usually analyze a sample collected from the nose. Molecular tests,
including PCR-based tests, are generally more sensitive than rapid antigen
tests. Multiplex tests can check one sample for RSV, influenza and COVID-19.

A healthcare professional may also use pulse oximetry to measure blood oxygen.
If pneumonia or another complication is suspected, additional evaluation may
include blood tests or chest imaging. These tests are not automatically needed
for every child with typical, uncomplicated bronchiolitis.

RSV Treatment

There is no routine medication that eliminates RSV in otherwise healthy
patients. Treatment is mainly supportive, meaning it keeps the person
comfortable, hydrated and adequately oxygenated while the immune system clears
the infection.

How to Manage Mild RSV at Home

• Encourage frequent fluids to reduce the risk of dehydration.
• Offer infants smaller, more frequent feedings if normal feeding is tiring.
• Use saline nose drops and gentle nasal suction for a congested baby.
• Allow plenty of rest.
• Use a clean cool-mist humidifier when dry air worsens congestion.
• Keep the patient away from tobacco smoke, vaping aerosols and strong fumes.
• Monitor breathing, alertness, fluid intake and urine output.

Acetaminophen or ibuprofen may reduce fever and discomfort when appropriate for
the patient’s age and medical history. A clinician or pharmacist can confirm the
correct product and dose. Ibuprofen is generally not used in infants younger
than 6 months unless a healthcare professional specifically recommends it.

Never give aspirin to a child or teenager with a viral illness because of the
risk of Reye syndrome. Over-the-counter cough and cold products are also unsafe
or unhelpful for many young children, so parents should check with a pediatrician
before using them.

What Does Not Routinely Treat RSV?

Antibiotics do not kill RSV because RSV is a virus. They may be prescribed only
if a clinician identifies a separate bacterial infection, such as certain cases
of bacterial pneumonia or an ear infection.

Bronchodilators, corticosteroids and chest physical therapy are not routinely
recommended for typical infant bronchiolitis because most babies do not benefit
from them. A clinician may make a different decision when another condition,
such as asthma, is involved. Antiviral treatment is reserved for unusual,
carefully selected situations rather than ordinary outpatient RSV.

Hospital Treatment for Severe RSV

People with serious breathing difficulty, low oxygen or dehydration may need
hospital care. Treatment can include:

• Supplemental oxygen
• Nasal suctioning and airway support
• Fluids delivered through an intravenous line
• Tube feeding when an infant cannot safely drink enough
• High-flow oxygen or other noninvasive breathing support
• Mechanical ventilation in the most severe cases

Hospital teams continually reassess breathing effort, oxygen level and
hydration. Most hospitalized patients improve with supportive care, although
recovery time depends on age, disease severity and underlying health conditions.

When to Call a Doctor

Contact a healthcare professional when symptoms are worsening rather than
improving, particularly in an infant, an older adult or anyone with a serious
medical condition. Parents should also call when a baby is eating substantially
less, producing fewer wet diapers, breathing faster or behaving unusually.

A rectal temperature of 100.4°F (38°C) or higher in a baby younger than 3 months
requires prompt medical evaluation, even when the infant otherwise appears
comfortable.

RSV Emergency Warning Signs

Seek emergency care immediately for:

• Severe difficulty breathing or struggling for every breath
• Long pauses in breathing
• Blue, gray or unusually pale lips, face or skin
• Strong chest retractions or persistent grunting
• Inability to drink or keep fluids down
• Clear signs of dehydration, including very few wet diapers
• Extreme weakness, confusion or difficulty waking
• Chest pain or rapidly worsening shortness of breath

Caregivers do not need to count every breath with laboratory precision. If a
child appears to be working hard to breathe, looks different in color or cannot
feed because of breathing trouble, it is safer to seek help.

How to Prevent RSV

Everyday respiratory precautions reduce transmission. Wash hands with soap and
water, avoid touching the face with unwashed hands and clean frequently touched
surfaces. Improve indoor airflow when practical, cover coughs and sneezes and
avoid close contact with high-risk people while sick.

People with respiratory symptoms should remain home and away from others until
their symptoms are improving overall and they have been fever-free for at least
24 hours without fever-reducing medicine. Additional precautions, such as
masking and better ventilation, can help protect others during the following
days.

RSV Vaccination for Adults

Current CDC guidance recommends a single dose of RSV vaccine for all adults age
75 and older and for adults ages 50 through 74 who have an increased risk of
severe RSV disease. Risk may be higher with chronic heart or lung disease,
immune suppression, frailty or residence in a long-term care facility.

RSV vaccination is not currently treated as an automatic annual vaccine. Adults
should discuss eligibility and timing with a healthcare professional because
recommendations can change as new evidence becomes available.

Protecting Infants from Severe RSV

Two prevention strategies are available for most infants: maternal RSV
vaccination during pregnancy or a long-acting RSV antibody administered to the
baby. In most of the United States, the maternal vaccine is recommended during
weeks 32 through 36 of pregnancy between September and January.

An infant RSV antibody is generally recommended for babies entering their first
RSV season when the mother was not vaccinated during pregnancy, her vaccination
status is unknown or the baby was born soon after maternal vaccination. Some
children at increased risk may also qualify during their second RSV season.
Most babies do not require both maternal vaccination and infant antibody
protection.

Caregiving Experiences: What RSV Can Look Like Day by Day

RSV rarely begins with a dramatic announcement. A common caregiving experience
starts with a slightly runny nose and a child who seems less interested in
breakfast. On the first day, the illness may look so ordinary that no one gives
it a memorable name. By the second or third day, congestion may increase and
feeding can become slower because babies have difficulty coordinating sucking,
swallowing and breathing through a blocked nose.

This is why experienced caregivers often pay more attention to breathing and
hydration than to the loudness of the cough. A cough can sound frightening
while a child is still breathing comfortably, drinking and playing. In another
child, the cough may sound modest while the skin beneath the ribs pulls inward
with each breath. The second situation is more concerning, even if the living
room is not yet producing medical-drama sound effects.

One practical lesson is to observe a baby while calm. Crying naturally makes
breathing faster and noisier. When the baby settles, caregivers can look at the
chest and abdomen, listen for grunting and notice whether the nostrils flare.
They can also record a short video of unusual breathing to show a clinician,
provided doing so does not delay urgent care.

Feeding often becomes the household’s unofficial RSV measuring tool. A
congested baby may take a few sips, stop to breathe and then become too tired to
finish. Saline drops and gentle suction shortly before feeding can make the job
easier. Smaller amounts offered more frequently may be better tolerated than
insisting on a normal full feeding. Counting wet diapers gives caregivers a
clearer picture of hydration than guessing from mood alone.

The third through fifth days of illness are often the period when pediatric RSV
symptoms feel most intense. That does not mean every child will worsen, but it
explains why a baby who looked mildly congested yesterday may need closer
observation today. Families sometimes expect improvement immediately after a
positive test, as though identifying the virus has offended it into leaving.
Unfortunately, the test provides information, not an eviction notice.

Caring for an older adult with RSV presents a different set of clues. The
person may describe unusual exhaustion, worsening shortness of breath or a
decline in their ability to walk around the home. Someone with COPD or heart
failure may notice symptoms from that condition becoming harder to control.
Families should not dismiss sudden confusion or severe weakness as “just a
cold,” particularly when the person is not drinking enough or appears short of
breath.

Another real-world lesson is that home monitoring should have clear limits.
Caregivers may feel tempted to watch symptoms for one more hour, especially
during the night. A useful threshold is simple: color change, breathing pauses,
severe chest retractions, inability to drink, marked dehydration or difficulty
waking is not a “wait until morning” situation.

Recovery can also be uneven. Fever and nasal congestion may improve before the
cough disappears. Appetite often returns gradually, and sleep schedules may
remain scrambled for several days. Improvement should be judged by the overall
direction: easier breathing, more fluid intake, better alertness and longer
comfortable periods.

Finally, caregivers need care too. Taking shifts, writing down medication times
and asking another adult to handle meals or household chores can prevent errors
caused by exhaustion. RSV may be a tiny virus, but it has impressive talent for
turning an ordinary week into a complicated group project.

Conclusion

RSV is usually a mild respiratory infection, but it can cause bronchiolitis,
pneumonia and dangerous breathing difficulty in infants, older adults and
people with certain health conditions. Early symptoms often resemble a cold,
so the most useful clues are changes in breathing, feeding, hydration, skin
color and alertness.

Most cases improve with rest, fluids and supportive care. Severe breathing
problems, dehydration, apnea or color changes require immediate medical
attention. Vaccination, infant antibody protection and sensible respiratory
hygiene can substantially reduce the risk of severe disease.