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

INITIAL

close contact of confirmed or probable case

1st line – observation ± post-exposure neuraminidase inhibitor

Back
INITIAL
|
close contact of confirmed or probable case
1st line – 

observation ± post-exposure neuraminidase inhibitor

Contacts should be monitored closely for signs of illness for up to 10 days following exposure. If the person develops a compatible illness during this time, the person should be treated as a possible case.

The 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. Local or national public health departments should be contacted for guidance.[111][112] 

The US Centers for Disease Control and Prevention (CDC) recommends post-exposure antiviral chemoprophylaxis with a neuraminidase inhibitor in highest-risk exposure groups. It may be considered in moderate-risk exposure groups, and is not routinely recommended in low-risk exposure groups. The decision to start chemoprophylaxis in low- or moderate- risk groups should be based on clinical judgement, consideration of the type of exposure, and whether the contact is at high risk for complications.[127]

Chemoprophylaxis may be considered for people who are exposed to birds with avian influenza A virus infection. The decision to initiate chemoprophylaxis should be based on clinical judgement, with consideration given to the type and duration of exposure, time since exposure, known infection status of bird(s), and whether the exposed person is at higher risk for complications.[128]

Administration should begin as soon as possible, within 48 hours after possible exposure, and continue for 5 or 10 days. If exposure was time-limited and not ongoing, chemoprophylaxis is recommended for 5 days from the last known exposure. If exposure is likely to be ongoing (e.g., household setting), 10 days is recommended.[127]

Oral oseltamivir is recommended for people of any age, including newborn infants. Inhaled zanamivir is recommended for people ≥5 years of age, but is not recommended for people with underlying airway disease.[127] Oseltamivir is the preferred option in pregnant women.[131]

The CDC recommends that chemoprophylaxis should be given twice daily (i.e., the treatment dosing frequency) rather than once daily (i.e., the typical seasonal influenza antiviral chemoprophylaxis dose) because of the potential that Asian lineage A(H7N9) virus infection may have already occurred. However, the dose may vary depending on location, and local guidelines should be consulted.[127]

Children may experience unique cutaneous, behavioural, and neurological adverse events with neuraminidase inhibitors; therefore, extra caution should be used in this population.

Recommended doses are based on guidelines from the CDC.[131]

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 ≥1 year of age and >15-23 kg body weight: 45 mg orally twice daily for 5-10 days; children ≥1 year of age and >23-40 kg body weight: 60 mg orally twice daily for 5-10 days; children ≥1 year of age and >40 kg body weight and adults: 75 mg orally twice daily for 5-10 days

More

Secondary options

zanamivir inhaled: children ≥5 years of age and adults: 10 mg (2 puffs) inhaled twice daily for 5-10 days

More
ACUTE

suspected or probable or confirmed infection

1st line – infection prevention and control

Back
ACUTE
|
suspected or probable or confirmed infection
1st line – 

infection prevention and control

Patients with suspected, probable, or confirmed Asian lineage A(H7N9) virus infection should be isolated and local infection control recommendations followed. If an airborne infection isolation room is not available, the patient should be isolated in a private room. Given the potential infectiousness and virulence of Asian lineage A(H7N9) virus, enhanced infection control precautions are recommended, including airborne and contact precautions (with the use of eye protection), in addition to standard precautions.[119]

There may be slight infection control recommendation differences between national public health organisations; therefore, if Asian lineage A(H7N9) virus infection is considered in a patient, it is recommended that clinicians consult national infection control guidelines.

Patients may be treated as outpatients or in hospital depending on disease severity and clinical presentation.

Plus – antiviral treatment

Back
ACUTE
|
suspected or probable or confirmed infection
Plus – 

antiviral treatment

Treatment recommended for ALL patients in selected patient group

Antiviral treatment is recommended as soon as possible for suspected, probable, or confirmed cases of Asian lineage A(H7N9) virus infection, even if more than 48 hours has elapsed since onset of symptoms, and regardless of disease severity. Antiviral treatment should not be delayed by diagnostic specimen collection or laboratory testing.[130] Antiviral therapy can be discontinued in patients who are not hospitalised and who test negative for Asian lineage A(H7N9) virus infection (or other influenza viruses).

Oral oseltamivir is the most widely studied and available. The World Health Organization (WHO) recommends oseltamivir as the preferred treatment for people with suspected or confirmed influenza virus infection (including zoonotic influenza) with or at risk of severe illness, based on low-quality evidence.[129] The US Centers for Disease Control and Prevention (CDC) recommends oseltamivir treatment as soon as possible for all hospitalised patients with suspected or confirmed novel influenza A virus infection associated with severe disease (e.g., H5N1, H5N6, H7N9) regardless of time since onset of illness, and all outpatients (i.e., any patient in the ambulatory care setting, including emergency departments, urgent care, and other clinics) including those with severe, progressive, or complicated illness. Oseltamivir is the only treatment for influenza recommended in outpatients if more than 48 hours have elapsed since onset of symptoms. For untreated outpatients with uncomplicated disease and no fever where symptoms are nearly resolved, the decision to start antiviral treatment should be based on clinical judgement.[130] Oseltamivir is recommended for people of any age, including newborn infants. It is the preferred option in pregnant women.[131]

Inhaled zanamivir may be an alternative option in non-intubated patients who do not have underlying airway disease (e.g., COPD, asthma). The WHO suggests not administering zanamivir to people with suspected or confirmed influenza virus infection (including zoonotic influenza) with or at risk of severe illness, based on very low-quality evidence.[129] The CDC recommends zanamivir only in outpatients with uncomplicated mild to moderate illness presenting within 2 days of onset of symptoms. It is not recommended in hospitalised patients due to a lack of safety and efficacy data in this population.[130]

Other neuraminidase inhibitors may be available in certain jurisdictions. The WHO suggests not administering intravenous peramivir or inhaled laninamivir to patients with suspected or confirmed influenza virus infection (including zoonotic influenza) with or at risk of severe illness, based on very low-quality evidence.[129] The CDC recommends intravenous peramivir only in outpatients with uncomplicated mild to moderate illness presenting within 2 days of onset of symptoms. It is not recommended in hospitalised patients due to a lack of safety and efficacy data in this population; however, it may be considered as an alternative to oseltamivir for patients who cannot tolerate or absorb oral oseltamivir because of suspected or known gastric stasis, malabsorption, or gastrointestinal bleeding.[130]

Oral baloxavir is a newer antiviral agent with a different mechanism of action to neuraminidase inhibitors. The WHO does not currently recommend baloxavir for patients with suspected or confirmed influenza virus infection (including zoonotic influenza) with or at risk of severe illness due to a lack of data in this population.[129] The CDC recommends baloxavir only in outpatients with uncomplicated mild to moderate illness presenting within 2 days of onset of symptoms.[130]

Children may experience unique cutaneous, behavioural, and neurological adverse events with neuraminidase inhibitors; therefore, extra caution should be used in this population.

Modified regimens with higher doses and longer duration of treatment oseltamivir (e.g., 10 days) may be considered on a case-by-case basis under specialist guidance (e.g., severely immunocompromised patients, severe or critical disease), but there are no available clinical trial data to reliably inform recommendations. Consult an infectious disease specialist for guidance.

Oral oseltamivir may be given enterically/nasogastrically. 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.[149][150]

Where the clinical course remains severe or progressive despite antiviral treatment, it is recommended that monitoring of Asian lineage A(H7N9) virus replication and shedding is performed, along with antiviral drug susceptibility testing. Contacting local or national public health departments for guidance is highly recommended.

Recommended doses are based on guidelines from the CDC.[131]

Primary options

oseltamivir: children <14 days of age: consult specialist for guidance on dose; 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 ≥1 year of age and >15-23 kg body weight: 45 mg orally twice daily for 5 days; children ≥1 year of age and >23-40 kg body weight: 60 mg orally twice daily for 5 days; children ≥1 year of age and >40 kg body weight and adults: 75 mg orally twice daily for 5 days

Secondary options

zanamivir inhaled: children ≥7 years of age and adults: 10 mg (2 puffs) inhaled twice daily for 5 days

Tertiary options

peramivir: children 6 months to 12 years of age: 12 mg/kg intravenously as a single dose, maximum 600 mg/dose; children ≥13 years of age and adults: 600 mg intravenously as a single dose

More

OR

baloxavir marboxil: children ≥5 years of age (body weight <20 kg): 2 mg/kg orally as a single dose; children ≥5 years of age and adults (body weight 20-79 kg): 40 mg orally as a single dose; children ≥5 years of age and adults (body weight ≥80 kg): 80 mg orally as a single dose

Consider – supportive care

Back
ACUTE
|
suspected or probable or confirmed infection
Consider – 

supportive care

Additional treatment recommended for SOME patients in selected patient group

Most patients hospitalised with confirmed Asian lineage A(H7N9) virus infection have rapidly progressive viral pneumonia leading to acute respiratory distress syndrome (ARDS) with variable multi-organ failure.[33][110] Based on observational data from treatment of patients with seasonal influenza, A(H1N1)pdm09, or HPAI A(H5N1) virus infection, early recognition of disease and initiation of antiviral and supportive therapies may improve clinical outcomes.

While there is no standardised approach for the clinical management of humans with Asian lineage A(H7N9) virus infection, the WHO recommends that supportive care follows published evidence-based guidelines for the clinical syndrome present (e.g., septic shock, respiratory failure, and ARDS).[1][146]

The WHO suggests not administering corticosteroids to patients with suspected or confirmed influenza virus infection (including zoonotic influenza) with or at risk of severe illness, based on very low-quality evidence. This recommendation is based on observational studies, and acknowledges the signal for increased risk of mortality with corticosteroids (although this finding is confounded by indication and time-dependent biases). However, corticosteroids should still be considered for other concurrent indications, when consistent with other recommendations (e.g., septic shock, asthma exacerbations, COPD).[129]

back arrow

Choose a patient group to see our recommendations

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

Use of this content is subject to our disclaimer