Overview
Definition:
Influenza antivirals are medications specifically designed to inhibit the replication of the influenza virus
They are crucial for managing influenza, particularly in preventing severe illness and complications, especially in vulnerable pediatric populations.
Epidemiology:
Influenza is a significant cause of morbidity and mortality in children worldwide
Annual epidemics occur, with peak incidence in temperate regions during winter months
Pediatric hospitalizations due to influenza are substantial, with certain age groups and individuals with underlying health conditions at higher risk for severe outcomes.
Clinical Significance:
Early and appropriate use of antiviral medications can shorten the duration of illness, reduce symptom severity, and decrease the risk of complications such as pneumonia, otitis media, and exacerbations of chronic conditions
Identifying high-risk children is paramount for timely intervention and effective management, directly impacting patient outcomes and reducing healthcare burden
This is a key area tested in DNB and NEET SS examinations.
High Risk Groups
Definition High Risk:
Children at increased risk for influenza complications include those with certain underlying medical conditions and those of very young age.
Medical Conditions:
Asthma or reactive airway disease
Neurologic or neuromuscular conditions affecting respiratory function
Chronic lung disease (excluding asthma)
Congenital heart disease
Conditions that can compromise respiratory function (e.g., spinal cord injuries)
Metabolic disorders
Diabetes mellitus
Renal, hepatic, or hematologic disorders
Immunosuppression (e.g., congenital or acquired immunodeficiency, including chemotherapy or prolonged corticosteroid use)
Children receiving long-term aspirin therapy due to risk of Reye's syndrome.
Age Groups:
Infants younger than 1 year of age are at higher risk for hospitalization and complications
Children aged 6 months to 5 years are also considered at increased risk.
Other Risk Factors:
Children who are pregnant or postpartum (though less common in pediatrics, important for adolescents)
Residents of nursing homes or other long-term care facilities
Children with extreme obesity.
Timing Of Treatment
Initiation Window:
Antiviral treatment is most effective when initiated as soon as possible, ideally within 48 hours of symptom onset
Prompt treatment can shorten illness duration and reduce complications.
Extension Beyond 48 Hours:
In children with severe, progressive, or complicated influenza, or those at high risk for complications, antiviral treatment should still be initiated even if more than 48 hours have passed since symptom onset
The potential benefits may outweigh the risks.
Prophylaxis:
Antiviral prophylaxis may be considered for unvaccinated high-risk individuals exposed to influenza, particularly in outbreak settings or when vaccine is not yet effective
However, vaccination remains the primary preventive strategy.
Management Strategies
Indications For Antivirals:
Antiviral treatment is recommended for all children with suspected or confirmed influenza who have been ill for less than 48 hours and have severe or progressive illness, or who are at high risk of influenza complications.
Oseltamivir Dosing Pediatrics:
Weight-based dosing is critical
For children weighing <15 kg: 3 mg/kg per dose, twice daily
For children weighing 15-23 kg: 45 mg per dose, twice daily
For children weighing 24-40 kg: 60 mg per dose, twice daily
For children weighing >40 kg: 75 mg per dose, twice daily
Duration is typically 5 days.
Baloxavir Marboxil Dosing:
For children aged 12 years and older: Weight-based dosing is available
For children weighing 40 kg to <50 kg: 20 mg once
For children weighing 50 kg to <80 kg: 40 mg once
For children weighing ≥80 kg: 80 mg once
Single dose.
Supportive Care:
Adequate hydration
Rest
Antipyretics (acetaminophen or ibuprofen)
Monitoring for signs of respiratory distress or worsening condition
Prompt evaluation of complications like pneumonia or sepsis.
Complications And Prevention
Common Complications:
Pneumonia (viral or secondary bacterial)
Otitis media
Sinusitis
Bronchiolitis
Exacerbation of chronic conditions (asthma, heart disease)
Dehydration
Myositis
Reye's syndrome (associated with aspirin use)
Encephalitis
Myocarditis.
Prevention Of Complications:
Primary prevention through annual influenza vaccination is the most effective strategy for all children 6 months and older
Prompt antiviral treatment in symptomatic individuals, especially high-risk groups, can prevent or mitigate complications
Good hand hygiene and respiratory etiquette reduce transmission.
Antibiotic Use:
Antibiotics are indicated only for confirmed or suspected bacterial coinfections, not for influenza itself
Careful clinical assessment is required to differentiate viral from bacterial pneumonia.
Key Points
Exam Focus:
Always identify high-risk pediatric patients
Know the 48-hour rule for antivirals, but when to treat even beyond it
Master the weight-based dosing of oseltamivir for children
Understand the mechanism and indication of baloxavir.
Clinical Pearls:
Suspect influenza in any febrile child with respiratory symptoms during influenza season
Remember that influenza can present with gastrointestinal symptoms in children
Emphasize vaccination as the cornerstone of prevention
Be aware of increasing antiviral resistance patterns globally.
Common Mistakes:
Delaying antiviral treatment until symptoms are severe or beyond the 48-hour window without considering high-risk status or severity
Incorrect dosing of oseltamivir in pediatric patients
Over-reliance on rapid influenza diagnostic tests without considering clinical context
Prescribing antibiotics unnecessarily for uncomplicated influenza.