Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
Primary options
oseltamivir: children ≥3 months of age: 3 mg/kg orally twice daily for 5-10 days; children >1 year of age and ≤15 kg body weight: 30 mg orally twice daily for 5-10 days; children >15-23 kg body weight: 45 mg orally twice daily for 5-10 days; children >23-40 kg body weight: 60 mg orally twice daily for 5-10 days; children >40 kg body weight and adults: 75 mg orally twice daily for 5-10 days
MoreSecondary options
zanamivir: children ≥7 years of age and adults: 10 mg (2 puffs) inhaled twice daily for 5-10 days
MoreThe decision to use antiviral chemoprophylaxis should be considered on a case-by-case basis and guided by assessment of Asian lineage A(H7N9) virus exposure and subsequent risk of developing infection. No prospective clinical trials exist to guide interim World Health Organization (WHO) chemoprophylaxis recommendations. The WHO does not recommend routine post-exposure antiviral chemoprophylaxis for close contacts, but it may be considered under certain circumstances. Recommendations are based on chemoprophylaxis following exposure to other influenza virus subtypes, including A(H1N1)pdm09 and highly pathogenic avian influenza (HPAI) A(H5N1). Note that twice-daily administration (same as treatment dosing frequency is recommended) to reduce the risk of emergence of antiviral resistance.
The WHO recommends close observation and post-exposure oseltamivir or zanamivir chemoprophylaxis for healthcare workers after unprotected close exposure to a symptomatic, suspected, or confirmed Asian lineage A(H7N9) case (within 2 m) in the healthcare setting, as well as for household members and close contacts of a person with suspected or confirmed Asian lineage A(H7N9) virus infection. Note CDC guidance states that unprotected exposure of healthcare workers is associated with moderate risk of infection and that chemoprophylaxis should be considered in this group.
Treatment course: 5 days (if time-limited exposure, not ongoing) or 10 days (if exposure is ongoing).
Primary options
oseltamivir: children <14 days of age: 3 mg/kg orally once or twice daily for 5 days; children 14 days to 1 year of age: 3 mg/kg orally twice daily for 5 days; children >1 year of age and ≤15 kg body weight: 30 mg orally twice daily for 5 days; children >15-23 kg body weight: 45 mg orally twice daily for 5 days; children >23-40 kg body weight: 60 mg orally twice daily for 5 days; children >40 kg body weight and adults: 75 mg orally twice daily for 5 days
MoreSecondary options
zanamivir: children ≥7 years of age and adults: 10 mg (2 puffs) inhaled twice daily for 5 days
MoreWhen Asian lineage A(H7N9) virus infection is highly suspected, isolating the patient (either within a hospital or while being monitored at home, as per local public health policies) and starting empiric neuraminidase inhibitor treatment as soon as possible according to existing guidelines while waiting for the results of specific laboratory tests is appropriate. As of June 2017, oseltamivir resistance of Asian lineage A(H7N9) virus is uncommon, although resistance can develop rapidly during antiviral treatment and clinicians should be alert to this possibility.
It is important to note that Asian lineage A(H7N9) virus infections in humans appear to be rare, and physicians must consider alternative diagnoses when evaluating patients with suspected Asian lineage A(H7N9) virus infection.
During the 2009 H1N1 influenza pandemic, the World Health Organization (WHO) recommended the oseltamivir dose adjustments for children shown below. These dosages may be considered for the treatment of children with suspected Asian lineage A(H7N9) virus infection. The dosage for children is based on weight.
Oral or enterically administered oseltamivir is the recommended antiviral medication treatment.[147] Inhaled zanamivir might be used as an alternative regimen in nonintubated patients.[143]
Combination oseltamivir and zanamivir treatment is not recommended because of the potential for antagonism.[162]
Treatment recommended for ALL patients in selected patient group
Given the potential infectiousness and virulence of Asian lineage A(H7N9) virus, enhanced infection control precautions are recommended to prevent transmission by contact, droplet, and airborne routes. This is achieved by measures including appropriate patient placement (e.g., respiratory isolation), protection of staff and other contacts by using correct personal protective equipment, appropriate cleaning and disinfection protocols, and control of waste and potentially contaminated materials. All infection control strategies include standard hand hygiene precautions. There may be slight infection control recommendation differences between the World Health Organization[164] and some national public health organizations; therefore, if Asian lineage A(H7N9) virus infection is considered in a patient, it is recommended that clinicians consult national infection control guidelines.
Most patients hospitalized with Asian lineage A(H7N9) virus infection have had rapidly progressive pneumonia leading to acute respiratory distress syndrome (ARDS) and variable multi-organ failure.[37][115] Based on experience of treating patients with severe illness caused by A(H1N1)pdm09 and highly pathogenic avian influenza (HPAI) A(H5N1) virus infections, early recognition of disease and rapid initiation of antiviral and supportive therapies may improve clinical outcomes.[159][160][170][171][172]
While there is no standardized approach or specific guidance for the clinical management of humans with Asian lineage A(H7N9) virus infection, for HPAI A(H5N1) virus infection the World Health Organization (WHO) recommends supportive care that follows published evidence-based guidelines for the clinical syndrome present (e.g., septic shock, respiratory failure, and ARDS).[1][148] According to the WHO, patients who have severe or progressive clinical illness, including viral pneumonitis, respiratory failure, and ARDS due to influenza virus infection, should not be given systemic corticosteroids unless indicated for other reasons (e.g., adrenal insufficiency, refractory septic shock) or as part of an approved research protocol.[149] Interim guidance on treatment of Asian lineage A(H7N9) virus infection is guided by experience of treating severe illness due to A(H1N1)pdm09 and HPAI A(H5N1) virus infections.
Treatment recommended for ALL patients in selected patient group
Primary options
oseltamivir: children <14 days of age: 3 mg/kg orally once or twice daily for 5 days; children 14 days to 1 year of age: 3 mg/kg orally twice daily for 5 days; children >1 year of age and ≤15 kg body weight: 30 mg orally twice daily for 5 days; children >15-23 kg body weight: 45 mg orally twice daily for 5 days; children >23-40 kg body weight: 60 mg orally twice daily for 5 days; children >40 kg body weight and adults: 75 mg orally twice daily for 5 days
MoreSecondary options
zanamivir: children ≥7 years of age and adults: 10 mg (2 puffs) inhaled twice daily for 5 days
MoreIf exposure risk factors are present or suspected, empiric antiviral therapy should be initiated as early as possible. Antiviral therapy should not be delayed by diagnostic specimen collection or pending laboratory testing results. Oral or enterically administered oseltamivir is the recommended antiviral medication treatment.[1][147][153][154][155] Inhaled zanamivir might be used as an alternative regimen in nonintubated patients.[143]
Modified regimens with higher doses of oseltamivir and longer duration of treatment may be considered on a case-by-case basis, but there are no available clinical trial data to reliably inform recommendations.[143][173]
Oseltamivir has been shown to be adequately absorbed following nasogastric administration to mechanically ventilated adults with severe A(H1N1)pdm09 and highly pathogenic avian influenza (HPAI) A(H5N1) disease.[174][175]
During the 2009 H1N1 influenza pandemic, the World Health Organization (WHO) recommended the dose adjustments for children shown below. These dosages may be considered for the treatment of children with suspected A(H7N9) virus infection. An adult dose of oseltamivir 150 mg twice-daily is often used for critically ill patients.[142][143] Adjusting dosage is recommended for children and adults with renal impairment.[143] Oseltamivir is approved for use in patients aged 1 year or older.
Combination oseltamivir and zanamivir treatment is not recommended because of the potential for antagonism.[162]
Treatment recommended for ALL patients in selected patient group
Given the potential infectiousness of Asian lineage A(H7N9) virus and its ability to cause severe illness, enhanced infection control precautions are recommended to prevent transmission by contact, droplet and airborne routes. This is achieved by measures including appropriate patient placement (e.g., respiratory isolation), protection of staff and other contacts by using correct personal protective equipment, appropriate cleaning and disinfection protocols, and control of waste and potentially contaminated materials. All infection control strategies include standard hand hygiene precautions. There may be slight infection control recommendation differences between the World Health Organization[164] and some national public health organizations; therefore, if A(H7N9) is considered in a patient, it is recommended that clinicians consult national infection control guidelines.
Use of this content is subject to our disclaimer