FDA approves H5N1 influenza vaccine for pandemic use

May 2007

The FDA approved the first human vaccine against H5N1 avian influenza in April.

The vaccine, manufactured by Sanofi Pasteur, could be administered in the event that the H5N1 influenza virus develops the capability to spread from human to human, which could result in a worldwide pandemic, according to the FDA. The manufacturers designed the vaccine to create limited early protection before a vaccine tailored to the pandemic strain is developed and produced.

“The threat of an influenza pandemic is, at present, one of the most significant public health issues our nation and world faces. The approval of this vaccine is an important step forward in our protection against a pandemic,” said FDA commissioner Andrew C. von Eschenbach, MD.

The FDA licensed the vaccine for people aged 18 to 64 who could be at increased risk for exposure to the influenza virus. People receive the vaccine in two doses administered intramuscularly one month apart.

In a clinical study, 103 healthy adults received two 90 mcg doses of vaccine, which were administered 28 days apart. Three hundred other healthy adults received a lower dose of vaccine; 48 adults received placebo. The vaccine was well tolerated; the most common adverse events reported by patients were headache, general ill feeling, pain at the injection site and muscle pain.

Forty-five percent of those in the study who received the two 90 mcg doses developed antibodies at a level that is expected to reduce the risk for influenza, according to the FDA. However, current data on other vaccines suggest that people who did not develop optimal antibody levels may still have the potential to reduce disease severity, influenza-related hospitalizations and mortality.

Researchers are collecting data on vaccine safety and efficacy among other age groups; the FDA will receive that data in the near future.

National stockpile

The federal government purchased the vaccine to include in the U.S. Strategic National Stockpile for administration by public health officials if necessary, according to the FDA. The national stockpile contains medicine and medical supplies, which can be delivered to any state within 12 hours to protect the public during a public health emergency.

“The timing and severity of an influenza pandemic is uncertain, but the danger remains very real. We are working closely with other government agencies, global partners and the vaccine industry to facilitate the development, licensure and availability of needed supplies of safe and effective vaccines to protect against the pandemic threat,” said Jesse L. Goodman, MD, MPH, director of the Center for Biologics Evaluation and Research at the FDA.

For more information:

• Visit the government’s pandemic influenza website for more information on preparedness efforts at www.pandemicflu.gov.