Influenza in infants, including how to recognize early signs and implement appropriate management, is a major concern for many parents. The following article provides detailed and clinically relevant information on this condition.
Influenza is a viral illness and is more than just a runny nose or sore throat. Protecting infants and young children from influenza is critically important, as the infection can lead to severe illness in this age group. In rare cases, influenza may be fatal. In 2017, influenza was associated with a record number of pediatric deaths. Notably, the majority of children who died had not received influenza vaccination.
Can infants get influenza? Modes of transmission
Can infants contract influenza? The answer is yes. Influenza is highly contagious and can spread easily from person to person, including to newborns and young infants.
When an infected individual coughs or sneezes, influenza viruses are released into the air through respiratory droplets. Infants may become infected by inhaling virus-containing droplets or by touching contaminated objects, such as toys, and subsequently touching their nose, eyes, or mouth.
Individuals with influenza can transmit the virus to others beginning approximately one day before symptom onset and continuing for five to seven days after becoming ill. Those with severe influenza, as well as infants and young children, may remain contagious for a longer duration, particularly if symptoms persist.
What health problems can influenza cause in children?
In children under five years of age, influenza may lead to several complications, including:
- Worsening of chronic medical conditions, such as congenital heart disease or bronchial asthma
- Neurologic complications, including encephalopathy
- Dehydration, meaning the child does not have sufficient fluids in the body
- Pneumonia, an infection affecting one or both lungs
- Sinus complications and otitis media. The sinuses are air-filled cavities within the facial bones surrounding the nose, and sinusitis may occur when fluid accumulates within these spaces
- Death. Although rare, influenza-related complications can occasionally be fatal
Early recognition and appropriate management are essential to reduce the risk of these serious outcomes.
What are the signs and symptoms of influenza in infants?
Common signs and symptoms of influenza in infants include:
- Marked fatigue or unusual drowsiness
- Cough
- Fever of 38.5°C or higher, chills, or shivering. Not all infants with influenza develop fever.
- Headache, muscle aches, or generalized body aches
- Rhinorrhea or nasal congestion
- Sore throat
- Vomiting or diarrhea
Clinical presentation may vary depending on the infant’s age and overall health status.
Influenza typically has an abrupt onset. Fever and most other signs and symptoms may persist for one week or longer. Although infants are unable to verbally describe how they feel, those with influenza often appear more ill, irritable, and uncomfortable compared with infants who have a common cold. If parents suspect that their child has influenza, even if the child has already received influenza vaccination, they should contact or bring the infant to the nearest healthcare facility for medical evaluation and support.
Seek emergency medical care immediately if the child develops any of the following signs or symptoms:
- Persistent irritability or inconsolable crying throughout the day
- Pale or bluish discoloration of the face or lips
- Worsening of chronic medical conditions, such as asthma
- Rapid breathing, difficulty breathing, chest pain, or intercostal retractions with each breath
- Fever in infants younger than 12 weeks of age; fever above 38.5°C in older infants or children; or fever accompanied by a rash
- Fever or cough that improves but then recurs or worsens
- Seizures, defined as uncontrolled movements of the entire body or specific body parts
- Inadequate fluid intake or decreased urine output. Signs of dehydration include no urination for 8 hours, dry mouth, or absence of tears when crying
- Failure to awaken, decreased alertness, or lack of interaction with caregivers when awake
- Severe muscle pain, to the extent that the child is unable to walk
- Persistent or severe vomiting
How is influenza treated in infants and children?
A physician may prescribe antiviral medication to prevent or treat influenza in infants and children.
Antiviral agents are medications used to treat infections caused by viruses. In cases of influenza, antiviral therapy can reduce disease severity, shorten symptom duration, and help the child feel better sooner. Importantly, antivirals may also decrease the risk of serious complications, such as pneumonia. These medications are most effective when initiated within 48 hours of symptom onset. However, they must be prescribed and closely monitored by a physician.
If a child is considered at high risk for influenza-related complications, a physician may initiate antiviral treatment as soon as influenza symptoms begin. All children under five years of age are at increased risk, particularly those younger than two years. Preterm infants and children with chronic medical conditions, such as asthma or sickle cell disease, are also at elevated risk.
Three antiviral medications are approved for the treatment of influenza in children:
- Oseltamivir (Tamiflu®): approved for infants as young as two weeks of age. It is available in capsule and oral suspension forms.
- Zanamivir (Relenza®): approved for children aged five years and older. It is administered as an inhaled powder and is not recommended for individuals with underlying respiratory conditions such as asthma.
- Peramivir (Rapivab®): approved for children aged two years and older. It is administered intravenously by a healthcare professional.
If a child has influenza, ensure adequate rest and encourage sufficient fluid intake. The child may have a reduced appetite; offering small, frequent meals may help maintain nutritional support and promote recovery.
If the child appears uncomfortable due to fever, consult a physician regarding the appropriate use of acetaminophen (Tylenol®) or ibuprofen (Motrin® or Advil®) for infants or young children. Aspirin should not be administered without medical supervision. In children with viral illnesses such as influenza, aspirin use has been associated with Reye syndrome, a rare but potentially life-threatening hepatic and neurologic disorder.
If the child develops cough or cold symptoms, avoid over-the-counter cough and cold medications. According to the American Academy of Pediatrics, these products may cause serious adverse effects in young children. Medical consultation is essential before administering any medication to an infant or child.
Are infants more susceptible to influenza compared with other groups?
A frequently asked question is whether infants are more vulnerable to influenza or its complications compared with other populations.
The answer is yes. Certain children are at greater risk of developing serious influenza-related complications than others.
Infants and children under five years of age and especially those younger than two years are more likely to experience complications from influenza than older children. Preterm infants are also at increased risk of severe influenza-related outcomes.
The Centers for Disease Control and Prevention recommends that preterm infants receive most routine vaccinations, including the influenza vaccine, according to their chronological age (calculated from the date of birth), regardless of birth weight. Even if an infant was born small or with low birth weight, vaccination should generally follow the standard immunization schedule. Parents of preterm infants should consult their physician to ensure timely influenza immunization.
In addition, children with chronic medical conditions such as asthma, congenital or acquired heart disease, or hematologic disorders are at elevated risk for influenza complications and require particular vigilance.
How can influenza transmission be prevented in infants?
If you or your child has influenza, transmission to others can occur easily. The following measures help reduce the spread of infection:
- Keep the child at home and do not allow return to school or daycare until at least 24 hours after the fever has resolved (38.5°C or higher) without the use of antipyretic medication.
- Avoid close contact with others.
- Do not kiss the infant and avoid touching the eyes, nose, and mouth.
- Teach children to cough or sneeze into a tissue or into their elbow. Dispose of used tissues immediately.
- Wash hands thoroughly with soap and water before and after caring for the child. Adults may also use alcohol-based hand sanitizer, ensuring sufficient volume is applied and rubbed until hands are dry, typically for at least 15 seconds.
- Clean and disinfect frequently touched surfaces and toys that may be contaminated with influenza virus.
- Wash the child’s dishes and utensils with hot water and soap or in a dishwasher.
- Do not share eating utensils, drinking glasses, personal items, or toothbrushes.
Importantly, all individuals aged six months and older should receive annual influenza vaccination. This includes parents and caregivers, particularly those caring for infants younger than six months who are not yet eligible for vaccination. Immunization of household contacts significantly reduces the risk of transmission to vulnerable infants.
Annual influenza vaccination: the most effective preventive measure for infants
The Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) recommend that all individuals aged six months and older receive annual influenza vaccination.
Vaccination is particularly important for children under five years of age, as they are more likely to develop serious influenza-related complications compared with older children. Influenza can be dangerous for all children, including those who are otherwise healthy.
The most effective way to protect children from influenza is to ensure they receive annual vaccination before the start of the influenza season, which typically extends from October through May. Although influenza activity peaks during this period, infection can occur at any time of the year.
There are two methods for children to receive influenza vaccination:
- Influenza injection (inactivated influenza vaccine). Children aged six months and older are eligible to receive the influenza shot.
- Intranasal influenza vaccine (nasal spray). This formulation is administered as a spray into the child’s nose. Most children aged two years and older are eligible to receive the nasal spray vaccine. However, it is not recommended for children with certain medical conditions, such as asthma, chronic cardiac or pulmonary disorders, or immunodeficiency. The nasal spray vaccine is also not recommended for children receiving long-term aspirin therapy.
When a child receives influenza vaccination for the first time, two doses are typically required to achieve optimal immune protection. Thereafter, one dose is administered annually.
Reader may also be interested in:
- Flu symptoms in children and how to differentiate influenza from the common cold
- How dangerous is seasonal influenza in children and how can it be prevented?
- [Overview] Influenza A in children: what parents need to know
Influenza vaccination is considered safe for most children, including those born preterm before 37 weeks of gestation.
If the child has previously experienced an adverse reaction to influenza vaccination, parents should inform the physician so that appropriate post-vaccination monitoring can be arranged. If the child has an egg allergy, medical consultation is recommended to determine vaccine suitability, as some influenza vaccines are produced using egg-based manufacturing processes.
Influenza viruses continually evolve, and multiple strains circulate each season. Therefore, a new influenza vaccine formulation is developed annually to provide protection against three or four strains predicted to be most prevalent in the upcoming influenza season. Vaccine-induced immunity generally lasts about one year, making annual vaccination essential for sustained protection.
Note: The information provided in this article by Hong Ngoc General Hospital is for reference purposes only and does not replace professional medical diagnosis or treatment. Patients should not self-medicate. For an accurate evaluation of their medical condition, individuals should visit a healthcare facility for direct examination, diagnosis, and appropriate treatment counseling by a qualified physician.
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