The New Avian Influenza A (H7N9) Virus: What Clinicians Should Know

Alicia M. Fry, MD, MPH


May 09, 2013

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In This Article

Management of Uncomplicated Illness


Given the anticipated lack of preexisting immunity to H7N9 viruses; the potential for rapid progression, severe disease, and fatal outcomes with H7N9 infection; and low adverse event profile of neuraminidase inhibitors, treatment with oseltamivir or inhaled zanamivir should be initiated when confirmed cases, probable cases, or H7N9 cases under investigation are recognized, even if more than 48 hours from illness onset and even for apparently uncomplicated illness.

Antiviral treatment is recommended as soon as possible for all persons, even for previously healthy persons, and especially for those considered to be at increased risk for complications associated with influenza, such as children aged < 2 years, adults aged ≥ 65 years, pregnant women, and persons with certain underlying medical conditions. Please see Influenza Antiviral Medications: Summary for Clinicians for a complete list of groups considered to be at higher risk for influenza complications.

For outpatients with uncomplicated disease in whom fever is absent and symptoms are nearly resolved, decisions to initiate antiviral treatment should be based on clinical judgment. Persons who are not treated with antiviral medications should be monitored for progression of illness.

Inhaled zanamivir is not recommended for persons with underlying airway disease (eg, asthma or chronic obstructive pulmonary disease).

The recommended duration of treatment for uncomplicated illness is 5 days.

Hospitalized Patients

As with nonhospitalized patients, initiation of antiviral treatment is recommended as early as possible for hospitalized patients, even if more than 48 hours from illness onset.

For hospitalized patients and patients with severe or complicated illness, treatment with oral oseltamivir (and not inhaled zanamivir) is recommended because of the lack of data for inhaled zanamivir in patients with severe influenza illness.

The optimal duration and dose of therapy are uncertain in severe or complicated influenza. Pending further data, longer courses of treatment (eg, 10 days of treatment) should be considered for severely ill hospitalized H7N9 patients (See Interim Guidance on Use of Antiviral Agents for Treatment of Human Infections with Avian Influenza A [H7N9] for specific information.)

Although oral oseltamivir is well absorbed in critically ill patients, for patients who cannot tolerate or absorb oral medication because of suspected or known gastric stasis, malabsorption, or gastrointestinal bleeding, intravenous (IV) zanamivir should be considered. IV zanamivir is an investigational parenterally administered product available by enrollment in a clinical trial or compassionate use under an emergency investigational new drug (EIND) request to the manufacturer confirmed with US Food and Drug Administration. An IV zanamivir compassionate use request may be made by contacting the GSK Clinical Support Help Desk via email ( or by calling 1-877-626-8019 or 1-866-341-9160.

Visit the CDC Website for additional materials, including Interim Guidance for Infection Control Within Healthcare Settings When Caring for Patients with Confirmed, Probably, or Cases Under Investigation of Avian Influenza A (H7N9) Virus Infection.

CDC will provide updated information as it becomes available on the CDC Website Avian Influenza A (H7N9).

Alicia M. Fry, MD, MPH, is a medical officer and team lead for the Influenza Prevention and Control Team, Epidemiology and Prevention Branch, Influenza Division, within CDC's National Center for Immunization and Respiratory Diseases (NCIRD). She oversees epidemiologic activities related to influenza vaccine and antiviral effectiveness, antiviral resistance, as well as other projects related to the morbidity and mortality of influenza viruses.

Dr. Fry joined the CDC in 1999 as an Epidemic Intelligence Service officer in the Respiratory Diseases Branch of the Division of Bacterial and Mycotic Diseases. In subsequent years, she served as a medical officer in the division's Foodborne and Diarrheal Disease Branch and the International Activities Branch of the Division of Tuberculosis Elimination in the National Center for HIV, STD and TB Prevention. Prior to her current post, Dr. Fry was the medical officer and team lead for the Respiratory and Enterovirus team of the Epidemiology Branch in NCIRD's Division of Viral Diseases.

Dr. Fry earned her Doctorate of Medicine from the University of Cincinnati - College of Medicine in Ohio. After completing her residency in internal medicine at Johns Hopkins Hospital in Baltimore, Dr. Fry completed subspecialty training in infectious diseases and a molecular medicine fellowship at the University of California-San Francisco. She subsequently earned her Master of Public Health from the University of California-Berkeley. She is the author of more than 100 peer-reviewed journal articles. In addition to her work at the CDC, Dr. Fry serves as a clinician in the Infectious Diseases Clinic for the Veterans Administration Medical Center in Atlanta, Georgia.