What Is the First Sign of RSV? A Timeline of RSV Symptoms

If you’ve never had respiratory syncytial virus (RSV) before, you might not know what to expect. The illness usually causes mild, cold-like symptoms, and most people recover in a week or two.

You also may not know that you were even infected—though most people do contract the illness at some point during childhood.

“By 2 years of age, most children will have been infected by RSV at least once,” Michael Chang, MD, an infectious diseases expert at UTHealth Houston and Memorial Hermann Hospital, told Verywell. “Just 2% of all children are hospitalized with RSV in the first year of life, with up to 1 in 4 of hospitalized infants needing intensive care.”

It’s not just babies and kids, either. The Centers for Disease Control and Prevention (CDC) estimates that in adults over age 60, RSV leads to 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths per year.

Here’s a timeline of RSV symptoms, what you need to know about how it spreads, and steps you can take to protect yourself this winter.

How Do You Know If You Have RSV?

Sterling Ransone, MD, FAAFP, an American Academy of Family Physicians Board Chair and family physician, told Verywell that it can be hard to tell if you have RSV because the symptoms are similar to other viral infections, including the common cold, flu, and COVID-19.

The only way to know for sure that you have RSV is to get tested. There are rapid RSV antigen tests and molecular tests (RT-PCR).

Chang said that you can actually get tested for RSV, the flu, and COVID all at once, as “many testing sites offer combination testing for at least two or three of the viruses at the same time.”

What Are the First Signs of RSV?

Chang said that the first signs of RSV infection are similar to mild, cold-like symptoms. For most kids and adults, RSV infection starts with upper respiratory symptoms like nasal congestion and a runny nose. Some people may get a sore throat, too.

After two to three days, Chang said some people get a cough. Babies can develop a high fever—up to 103 to 104 degrees Fahrenheit—while adults usually just have a mild fever or no fever at all.

Ransone said that the first RSV symptoms you get may also depend on how old you are. For example, younger people often have a fever, coughing, trouble breathing, and runny nose while adults can get a cough or stuffy nose.

Other symptoms that can show up at different stages of an RSV infection include decreased appetite, sneezing, wheezing, irritability, fatigue, trouble breathing, and feeling run down.

RSV symptoms tend to develop four to six days after someone is exposed to the virus.

“If you’re around somebody who you think might have a cold, and then four to six days later you pop up with symptoms, it could very well be RSV,” Ransone said.

But it’s also possible you may not feel sick at all.

“Many adults can be exposed to the virus and have the disease or pass it on” without ever having symptoms, Ransone added.

Who Is Most at Risk for Severe RSV Symptoms?

Chang said that infants are the most at risk for severe RSV and may even need to be hospitalized if they get sick. RSV likes to infect the lower respiratory tract, so the already tiny airways of babies can get even narrower from inflammation and secretions caused by the infection.

“These infants may start breathing fast, coughing a lot, and many will develop wheezing when they exhale,” said Chang. Babies with RSV symptoms often have trouble breastfeeding or drinking from their bottles.

But babies aren’t the only ones who can get really sick—there are also some adults who are at high risk for severe RSV:

• Older adults
• Adults with chronic heart or lung diseases (such as asthma and chronic obstructive pulmonary disease)
• Adults with weakened immune systems
• Adults with other underlying medical conditions
• Adults living in nursing homes or long-term care facilities 

According to Chang, high-risk adults with RSV may experience fast breathing, shortness of breath, coughing, chest pain, or symptoms of viral pneumonia. Adults with an underlying chronic condition like heart failure may notice that symptoms like leg swelling and trouble lying flat at night may get worse if they have RSV.

Generally speaking, Chang said the symptoms of RSV that infants and adults have are similar and mostly affect the upper respiratory tract at first, then move to the lower respiratory tract after several days.

How Long Does RSV Last?

According to Chang, RSV infections typically last five to 10 days after the start of symptoms.

Day four or five of RSV tends to be the worst, symptom-wise. Some people who catch RSV can have a cough that lasts a few weeks.

It’s possible for infection to last a little longer for people with RSV severe enough to require hospitalization—up to three weeks for infants and two weeks for adults. Both infants and adults with underlying heart and lung disease will take the longest to recover from RSV, Chang said.

Do You Have to Isolate If You Have RSV? 

According to Chang, you do not have to isolate or quarantine if you catch RSV or are exposed to someone with RSV. That said, you should still stay home and avoid others if you have RSV since it can spread to others when you cough and sneeze, or touch a shared surface.

Chang recommends that you stay home for at least a day or two until your symptoms start getting better and you’ve been fever-free for at least 24 hours without taking fever-reducing medication. Parents should keep kids out of daycare and school until they’ve been fever-free for at least 24 hours without fever reducers and their symptoms are improving.

“While isolation and quarantine are not required for RSV, I still recommend trying to do so until symptoms are improved to minimize spread to others,” said Chang.

If you can’t avoid others while you have RSV, here are some steps experts recommend to limit the spread:

• Cover coughs and sneezes with a tissue or shirt sleeve (don’t use your hands)
• Wear a mask
• Wash your hands frequently with soap and water
• Avoid touching your face with unwashed hands
• Avoid close contact (e.g., kissing, shaking hands, and sharing food, cups, or utensils) with other people (especially infants and anyone else at risk for severe illness)
• Clean frequently touched surfaces like phones and doorknobs

How to Treat RSV Symptoms at Home 

There is no antiviral therapy, breathing treatments, or medications that have been proven to shorten the duration or reduce the severity of RSV infections. Chang said that treatment for RSV is only for symptoms, even for infants and adults who are hospitalized.

“We have to support the body until it can recover from RSV on its own, which may require supplemental oxygen, sometimes ventilators, IV fluids, and clearing secretions from the airways through suctioning or other airway clearance techniques,” said Chang.

If you have RSV symptoms, Chang recommends resting, hydrating, and taking fever-reducing medications, as needed.

“Be on the lookout for worsening symptoms, especially shortness of breath and fast breathing,” said Chang. If you experience any of these symptoms, including difficulty completing sentences or any change in home oxygen requirements or oxygen saturations, seek medical attention.