Flu in Babies: Symptoms, Treatment, and When to Call a Doctor

Infants are vulnerable to serious complications from the flu (influenza) — especially those who are too young to be vaccinated.

If you have an infant, it’s important to know how the flu can affect them. Babies often don’t show typical signs of the flu, and they can’t use words to tell you how they’re feeling. But we’ve got you covered with what to look for to keep your baby safe and what to do if you think your baby has the flu.

How to recognize flu symptoms in babies

Flu in babies is different from flu in adults — or even flu in toddlers and children. Your baby may have more subtle symptoms at first, which can make it tricky to know how they’re doing. Plus they can’t tell you that they’re sick or achy. But there are signs to watch for.

Flu symptoms in babies can include:

• Poor feeding: Your baby may eat less when they start to feel sick. Or they may have trouble eating if they can’t breathe easily. During flu season, you’ll want to pay close attention to how well your baby is nursing or drinking their bottles. Poor feeding might be your first clue that they’re getting sick. 

• Fussiness: Your baby may be fussier than normal when they have the flu. And many babies sleep more when they’re not feeling well.

• Vomiting or diarrhea: Unlike adults, children and babies can have vomiting or diarrhea when they’re sick with the flu. This puts them at risk for dehydration. Dehydration can happen quickly in babies. See their pediatrician if your baby isn’t making as many wet diapers as usual, or their diapers seem less full. These are signs of dehydration.

• Cough and nasal congestion: Like adults, babies and newborns with the flu can have cough and nasal congestion.

• Fever: High fever is another common symptom of flu in babies.

How long does the flu last in infants?

Most flu symptoms in babies go away after 7 to 10 days. Newborn or infant flu symptoms may get worse over the first 72 hours of their flu illness. Babies usually start to feel better over the next 2 to 3 days. Some babies get better quickly while others take a few days to get back to their usual level of activity. 

Which flu treatments are helpful for babies?

When your baby gets the flu, you’ll want to stay in close touch with their healthcare team. They may recommend flu treatments, such as:

• Antiviral medication: Oseltamivir (Tamiflu) is a prescription antiviral medication that can help treat the flu in babies. It's safe for infants as young as 2 weeks old. But Tamiflu works best when it’s taken within 48 hours of when symptom start. So it's best to contact your child's healthcare team as soon as possible if your baby shows signs of the flu.

• Hydration: Make sure to keep your baby well hydrated with breast milk or formula. Your child's healthcare team may also recommend oral rehydration solutions, like Pedialyte if your baby is 4 to 6 months old. Keep in mind, babies under 6 months old shouldn’t drink water or juice.

• Cool mist: If your baby has a stuffy nose, a cool mist humidifier can help ease congestion.

• Nasal saline and suctioning: You can also use nasal saline (saltwater) drops and gentle suctioning to relieve nasal congestion. 

Keep in mind that some common flu treatments for adults are not be safe for babies. For example, over-the-counter (OTC) cold medicines  — like those that treat cough, congestion, or pain — shouldn’t be given to babies unless a healthcare professional specifically recommends them. 

And although acetaminophen (Tylenol) is generally safe, it can hide a fever, which makes it hard to know how sick your baby is. Never give any OTC medicine to an infant younger than 3 months without talking with your healthcare team first. 

When to call a healthcare professional

Any baby younger than 3 months who gets a fever should get medical attention right away. A fever is a rectal temperature of 100.4°F (38°C) or higher. These babies might seem OK, but their illness can become severe quickly.

All babies younger than 2 years are at high risk for developing serious illness if they get the flu. This is especially true if they aren't fully vaccinated against the flu. Always let your child's healthcare team know right away if you think your baby might have the flu. 

If your baby has been diagnosed with the flu, call your pediatrician right away if your baby is:

• Not eating well and you’re worried about dehydration

• Not making several wet diapers a day

• Fussy and difficult to calm

• Sleepy and difficult to wake up

• Breathing fast or seems to have trouble breathing

When should you take your infant to the hospital?

There are times when babies need medical attention right away. During office hours, it can help to call your child’s pediatrician first. But if you can’t get in touch with anyone, or if you’re still concerned, take your baby to the hospital. 

Your infant needs medical attention quickly if they:

• Have trouble breathing

• Are very sleepy or difficult to wake up

• Are unable to eat

• Haven’t had wet a diaper for over 6 hours

• Are younger than 3 months and have a temperature of 100.4°F (38°C) or higher

Difficulty breathing is the most important reason to get your baby to the hospital right away. Signs of trouble can include fast or noisy breathing and breathing that interferes with eating or crying. When babies have trouble breathing, they might use their stomach and chest muscles or flare their nostrils. 

Call 911 if your baby looks blue or won’t wake up.

How to keep your infant from getting the flu

The flu vaccine can protect your baby against the flu during flu season. The flu vaccine is safe for babies older than 6 months. The first year your baby gets a flu shot, they’ll need 2 doses, 1 month apart. After that, they only need one dose each year.

Babies younger than 6 months are too young to get a flu shot. If your infant is too young to be vaccinated, here are some other things you can do to help protect them from the flu:

• Make sure everyone else in your home — and all of their caregivers outside the home — has been vaccinated against the flu. This builds a layer of protection around your baby.

• Keep your baby away from people who are sick. Some people get mild symptoms with the flu, but the germ is the same. Anyone who thinks they might be sick should stay away from your baby until they feel better.

• Wash your hands every time you cough, sneeze, or eat. And take special care to wash your hands before you touch your baby. 

How to keep your infant from spreading the flu

If your baby does get the flu, here’s how you can reduce the chance of passing it to others:

• Keep your child out of day care until they don’t have a fever for 24 hours without the help of acetaminophen.

• Wash your hands before and after touching or feeding your baby.

• Clean and disinfect anything that goes in your baby’s mouth. This includes cups, utensils, pacifiers, nipples, and toys.

• Encourage other children and adults in your home to wash their hands.

Should your child get a flu vaccine every year?

The American Academy of Pediatrics recommend that all children older than 6 months get vaccinated against the flu each year. 

Your child needs a yearly flu shot because the flu virus changes from year to year. That means the immune system can’t respond quickly enough without the help of vaccines for babies. 

The flu shot isn’t 100% effective. But children who are vaccinated against the flu and then get sick are less likely to develop serious illness.

Your child can get their flu shot at the same time as their other childhood vaccines. They can also get a flu shot at the same time as a COVID vaccine.

If your child isn’t feeling well, ask their pediatrician whether it’s okay to get the flu shot. Your child may still be able to get the flu shot if they have a cold or mild illness.

Why trust our experts?

Written by:

Brian Clista, MD

Dr. Clista is a board-certified pediatrician who works in private practice in Pittsburgh, Pennsylvania. He previously served as a National Health Service Corporation Scholar in the inner city of Pittsburgh for 11 years.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Our editorial standards

Meet our experts