What are the recommendations for influenza vaccination and treatment in the pediatric population, particularly for children aged 6 months and older with certain medical conditions such as asthma or heart disease?

Influenza Vaccination and Treatment in Pediatric Populations

Vaccination Recommendations

All children 6 months and older, including those with chronic medical conditions such as asthma or heart disease, should receive annual influenza vaccination. 1

Priority Groups Requiring Special Vaccination Effort

Children with the following conditions are at increased risk of influenza complications and require prioritized vaccination 1:

• Pulmonary diseases (including asthma)
• Hemodynamically significant cardiac disease
• Metabolic diseases (including diabetes mellitus)
• Hemoglobinopathies (including sickle cell disease)
• Immunosuppression
• Neurologic and neurodevelopmental disorders
• Infants born preterm (based on chronologic age, not corrected age)

Vaccine Selection and Dosing

Inactivated influenza vaccine (IIV), either trivalent or quadrivalent, is the primary recommended choice for all children. 1 The American Academy of Pediatrics specifically prioritizes IIV over live attenuated influenza vaccine (LAIV) because LAIV demonstrated inferior effectiveness against influenza A(H1N1) in recent seasons. 1

Age-specific dosing 2, 3:

• 6-35 months: Either 0.25 mL or 0.5 mL dose depending on the specific vaccine product
• 36 months and older: 0.5 mL dose

Two-dose requirement for young children 2, 3:

• Children 6 months through 8 years receiving influenza vaccine for the first time require 2 doses administered at least 4 weeks apart
• Both doses should ideally be administered before the end of October to ensure protection before peak influenza season

Special Considerations

Children with egg allergy of any severity can receive influenza vaccine without any additional precautions beyond those recommended for all vaccines. 1 This represents an important update that removes previous barriers to vaccination.

LAIV may be used as an alternative only for children who would not otherwise receive an influenza vaccine (e.g., refusal of IIV), are 2 years of age or older, and are healthy without underlying chronic medical conditions. 1

Timing of Vaccination

Vaccination should begin as soon as vaccine becomes available in the season. 2, 3 However, vaccination should continue throughout the influenza season as long as viruses are circulating, since influenza activity typically peaks in January or later in 75% of seasons. 3

Common Pitfalls to Avoid

• Do not delay vaccination in children with minor illnesses (mild upper respiratory symptoms, low-grade fever, or allergic rhinitis) - these are NOT contraindications. 3
• Do not use incorrect dosage based on age and specific vaccine product - verify the appropriate dose for each formulation. 2
• Do not fail to complete the two-dose series in first-time recipients under 9 years - this is essential for adequate immunity. 2, 3
• Do not administer LAIV within 2 weeks before or 48 hours after oseltamivir administration, as oseltamivir may inhibit replication of live vaccine virus. 4

Antiviral Treatment Recommendations

Antiviral treatment with oseltamivir is recommended for children with suspected or confirmed influenza who are hospitalized, have severe or progressive disease, or have underlying conditions that increase their risk of complications, regardless of duration of illness. 5

When to Initiate Antiviral Treatment

Treatment should be initiated as soon as possible - best results are seen when treated within 48 hours of symptom onset. 1 However, treatment is still recommended for high-risk children even if presenting beyond 48 hours. 5

Indications for Antiviral Treatment

Definite indications 5:

• Any hospitalized child with suspected or confirmed influenza
• Children with severe or progressive disease
• Children with underlying high-risk conditions (asthma, heart disease, immunosuppression, etc.)

Consider treatment for 5:

• Otherwise healthy outpatient children with suspected or confirmed influenza if treatment can be initiated within 48 hours
• Children whose siblings or household contacts are younger than 6 months or have high-risk conditions

Antiviral Chemoprophylaxis

Antiviral chemoprophylaxis is recommended as an adjunct to vaccination (not a substitute) for 5:

• Exposed children at high risk for influenza complications who have not yet been immunized
• Children who are not expected to mount an effective immune response to vaccination

Important Safety Considerations

Neuropsychiatric events: Closely monitor oseltamivir-treated patients for signs of abnormal behavior, including hallucinations, agitation, anxiety, delirium, and altered consciousness. 4 These events may occur with or without obvious severe disease.

Bacterial superinfection: Oseltamivir has not been shown to prevent secondary bacterial infections. Prescribers must remain alert to the potential for bacterial complications and treat appropriately. 4

Clinical Context and Burden of Disease

Children younger than 2 years are at increased risk of hospitalization and complications from influenza. 1 During the 2016-2017 season, hospitalization rates reached 41.4 per 100,000 for children 0-4 years old and 15.7 per 100,000 for children 5-17 years old, with 104 pediatric deaths reported. 1

Up to 80% of influenza-associated pediatric deaths have occurred in unvaccinated children 6 months and older, underscoring the critical importance of vaccination in reducing mortality. 3