RSV and Flu: What’s the Difference and When Should I Seek Care?

What is RSV? How is it different from the flu? When should I call my pediatrician or seek emergency care? Connecticut Children’s pediatric experts have the answers you need to get through respiratory season.

What is RSV and how serious can it get?

RSV is a virus that causes just one of many respiratory illnesses in infants, kids and even adults. For most of us, it’s not new and your child has likely already had it before turning 2. But RSV can be very serious for:

Infants a year or younger
Children younger than 2
Kids who are immunocompromised or who have existing lung disease, like asthma

RSV is also the most common cause for pneumonia and bronchiolitis (a fancy term for a bad cold—and different from bronchitis!) in very young kids.

How is RSV different than the flu?

RSV and the flu are two different viruses, but often have very similar symptoms. Sometimes, the symptoms are no more severe than that of a common cold. Other times, they can be life threatening.

Common symptoms of RSV:

Fever, but not always
Loss of appetite
Cough, often with wheeze. The cough can sound startling.
Runny nose

Common symptoms of the flu:

Body aches
Chills
Cough
Fatigue
Fever
Headache
Sore throat
Stuffy nose
Diarrhea and vomiting—sometimes

The kicker? It’s possible to have both the flu and RSV at the same time. An in-office test can confirm.

Antibiotics can treat both RSV and the flu, right?

No. Antibiotics do not work against viral infections. But if your child develops an ear infection from the congestion caused by the virus, your doctor may prescribe them to treat the newly formed infection. Sometimes, if appropriate and depending on how old your child is, your doctor may prescribe an antiviral like Tamiflu to lessen the severity of flu symptoms.

When should I call 911 or go to the emergency room?

Look for these signs:

Trouble breathing or fast breathing. Look for ribs pulling with each breath.
Change in color in face—usually bluish skin and lips
Fever of 100.4 or higher in infants younger than 3 months- call pediatrician on-call first
Fever of 105 or higher, regardless of age- call pediatrician on-call first
Fever of 102 or higher, lasting more than two days. This is to rule out any bacterial infections like meningitis.
Not alert when awake
Dehydration (no urine for 8 or more hours, mouth is dry and no tears are forming)- call pediatrician on-call first

In a true emergency, always call 911. Trust your parental instinct.

My child’s cough is never ending and gives me anxiety. Should I go to the ER for constant cough alone?

Usually not. Most of the time, while scary to hear, cough is our friend. It’s pushing out all the bad stuff and works to help your child ultimately get better. The challenge is, sometimes cough can be accompanied by wheezing or breathing difficulties—and it may get a lot worse at night.

If your child is having trouble breathing, definitely call 911. But for a cough alone, rest, a cold-mist humidifier, nebulizer if your doctor says so, elevating the mattress, and encouraging lots of fluids can all make a difference. Ask your pediatrician about FDA-approved medications that could help before you try administering anything on your own. Stay away from the homeopathic stuff as it hasn’t been studied in depth.

As a general rule, if your child’s cough hasn’t improved after two full weeks, give your pediatrician a call for a wellness check. There are so many factors—oftentimes unexplained—that can cause the “100-day” cough.

How can I prevent my child from getting either the flu or RSV?

1. Protection is always the best prevention!

For the flu: There is an FDA-approved influenza vaccine that comes out each year. Now is the time to make sure your child gets their flu shot at their pediatrician’s office. If you have an infant 6 months or older, and this is their first time, they’ll need two doses about a month apart. Your pediatrician will explain.
For RSV: The FDA has approved a monoclonal antibody that is available to children who meet certain criteria.

2. Consult your strategy toolbox, too.

Think back to all the strategies you pulled out of your toolbox during the many waves of COVID-19: wash hands, mask up when necessary and wipe down surfaces.

Juan C. Salazar, MD, MPH, FAAP

Juan Carlos Salazar, MD, MPH, is Professor and Chair of Pediatrics at the University of Connecticut School of Medicine and Executive Vice President and Physician-in-Chief at Connecticut Children’s.

In addition to serving in these roles, Dr. Salazar has led the Division of Pediatric Infectious Diseases and Immunology at Connecticut Children’s and has been nationally and internationally recognized for both his outstanding clinical care and his innovative research work. Dr. Salazar has received several National Institutes of Health grants to study the human innate immune response to Borrelia burgdorferi and Treponema pallidum, the causative agents of Lyme disease and syphilis respectively. He is currently funded by the NIH to develop a first of its kind syphilis vaccine. The NIH funded U-19 project includes investigators in China, Malawi, Colombia and the US. Most recently his team received funding from the National Institute of Child Health and Human Development (NICHD) to study the pathogenesis of COVID-19 and the multisystem inflammatory syndrome in children (MIS-C), a rare but serious condition associated with COVID-19. He has published over 100 peer reviewed articles and book chapters and has served in multiple scientific review panels at the NIH.

Dr. Salazar also directs the Pediatric and Youth HIV program at the Medical Center. His team has promoted and facilitated regional STD and HIV-prevention programs for at-risk high school youth. Dr. Salazar is the current recipient of Ryan White Care Act federal funding to coordinate and provide statewide HIV treatment and prevention services for women, infants, children and youth. He has conducted several NIH and pharmaceutical industry sponsored pediatric and adolescent HIV clinical trials and long-term follow-up studies.

He received his medical degree from the Universidad Javeriana, in Bogota, Colombia, and his MPH from the University of Minnesota. He completed a residency in Pediatrics at the University of Connecticut Health Center, where he also served as chief resident, and a post-doctoral fellowship in Pediatric Infectious Diseases at the University of Minnesota. He is board certified in both Pediatrics and Pediatric Infectious Diseases.