September 15, 2009 —The US Food and Drug Administration (FDA) announced today that it has approved 4 vaccines against the 2009 influenza A (H1N1) virus, formerly known as "swine flu." The vaccine lots are expected to be available and distributed within the next 4 weeks.
FDA Commissioner of Food and Drugs Margaret A. Hamburg, MD, said she thought Tuesday's approval was good news for the nation's response to the H1N1 influenza virus. "This vaccine will help protect individuals from serious illness and death from influenza," she said.
The approval comes at a time when the Centers for Disease Control and Prevention (CDC) is reporting that visits to physicians around the country for influenza-like illness are increasing and are higher than expected at this time of year. The vaccines that are currently available against 3 seasonal influenza virus strains will not protect against the 2009 H1N1 virus.
The FDA said that the vaccines, based on early data, effectively elicit an immune response in most healthy adults about 8 to10 days after vaccination. Clinical studies are still underway to produce an optimal dose for children, with results expected in the near future.
Meanwhile, the CDC stresses that influenza is primarily spread through person-to-person contact, by the coughing or sneezing of infected people, and recommends that infected people stay home and limit their contact with others to keep from infecting them.
The newly approved vaccines are being made by CSL Limited, MedImmune LLC, Novartis Vaccines and Diagnostics Limited, and Sanofi Pasteur Inc. All 4 firms reportedly use the same processes to manufacture the H1N1 vaccines. As with the seasonal influenza vaccine, some lots of the H1N1 vaccine will contain the preservative thimerosal and others will not. The FDA has been continuing its efforts toward reducing thimerosal used in vaccines.
The FDA warns that persons with known allergies to chicken eggs or any other substance in the vaccine should probably not be vaccinated, although in the ongoing clinical trials, the vaccines have been well tolerated. The most common adverse effect is soreness at the injection site; other adverse effects can include a mild fever, body aches, and fatigue for a couple of days after vaccination. For the nasal spray delivery system, the most common adverse effects were runny nose, nasal congestion in all ages, sore throats in adults, and fever in children aged 2 to 6 years.
The FDA is working with different organizations regarding adverse event monitoring, information sharing, and an overall analysis during and after the 2009 H1N1 vaccination program, according to the news release. "As with any medical product, unexpected or rare serious adverse events may occur," the FDA notes.