Avian Influenza Treatment & Management

Updated: Nov 17, 2015
  • Author: Nicholas John Bennett, MBBCh, PhD, MA(Cantab), FAAP; Chief Editor: Michael Stuart Bronze, MD  more...
  • Print
Treatment

Medical Care

The mainstay of treatment is the administration of antiviral medication.

Supportive care such as oxygen therapy, intravenous fluids and parenteral nutrition may be needed.

Severe cases may require ventilatory support with intubation and low-volume (high-frequency) ventilation.

Antiviral therapy should be tailored to the patient's age and the antiviral resistance profile of the virus from the area of exposure. Therapy should be initiated even when the presentation is late.

Antibiotics may be needed to treat bacterial pneumonia but are not empirically necessary.

Steroids have not been shown to be beneficial, except perhaps in the setting of sepsis with adrenal insufficiency. [9]

An important consideration is that of infection control and prevention of transmission to other patients and health care workers. Droplet precautions should be used, including eye protection. No evidence shows that airborne spread is possible, but, if fine aerosols are expected because of specific procedures, a particulate respirator should be properly fitted and used.

Adults and children older than 12 years require one week of infection-control precautions, from the initial onset of symptoms. Children younger than 12 years may shed high titers of human influenza virus for up to 21 days after the illness onset, and the World Health Organization (WHO) recommends the same duration for avian influenza precautions. [9]

Next:

Consultations

Consultation with an infectious disease expert is recommended.

Intensive care specialists need to be involved to manage severe disease.

Ultimately, the WHO and/or CDC should be contacted; the CDC can safely perform testing for suspected avian influenza strains.

Previous
Next:

Prevention

No vaccine is currently available to the public, although various products are in clinical trials and appear immunogenic. One complication is that the highly pathogenic viruses cannot be easily grown using the traditional embryonated chicken egg method, as the embryos often die during incubation. Alternative methods for producing immunogenic particles include tissue culture and reverse-genetic approaches using recombinant viruses. One option for increasing the immunogenicity (and hence potentially lowering the dose needed to vaccinate) is to use an adjuvant agent such as aluminum hydroxide. All of these methods are being evaluated for an avian influenza vaccine.

An H5N1 monovalent killed-virus vaccine produced by Sanofi-Pasteur has been approved by the US Food and Drug Administration (FDA) in the United States but is available only to government agencies and stockpiles. It is derived from the influenza A/Vietnam/1203/2004 strain isolated from humans, and is a formalin-inactivated/detergent-disrupted, purified virus grown in embryonated chicken eggs. The vaccine was approved based on a limited safety and immunogenicity study of 500 adults aged 18-64 years. Fewer than half of those receiving the highest dose of vaccine responded and achieved antibody titers expected to be fully effective (ie, hemagglutination inhibition antibody titers >1:40) based on experience with seasonal influenza. The vaccine contains thimerosal (unlike many other seasonal influenza vaccines) because of the need for multidose vials. [10]

A study of vaccination against Vietnam and Indonesian-origin H5N1 strains using a prime-boost strategy included 491 subjects. Optimal antibody titers required at least a 14-day interval between doses, and results were no better at 28 days. Some cross-reactivity was documented, but this was minimal at 1 month and was much better when 6 months had elapsed between doses. Although the use of a 6-month interval between vaccine doses is questionable in the setting of a pandemic, the authors suggest that priming at-risk individuals with an antigenically distant H5 influenza vaccine may have some effect in reducing the need for a 2-dose series later on. [11]

Prophylactic antivirals are not indicated for patients who plan to travel to areas where avian influenza has been reported. Travelers who plan to travel to areas of the world affected by avian influenza outbreaks in birds and/or humans are advised to avoid close contact with poultry, especially diseased or dead birds, and to consume only adequately cooked meat. If contact with birds in enclosed spaces is unavoidable, an N-95 respirator mask (or equivalent), gloves, and goggles should be used to minimize contact with droplets or particulates. PandemicFlu.gov details more specific travel recommendations.

Previous