A Better FLU Vaccine? Nasal Spray Vaccine May Give More Protection Against 'Drifted' Strains

New data from studies with FluMist by MedImmune Inc. show a strong antibody response against the virus that is currently circulating, a "drifted" strain.

"We have data to suggest that a live-virus vaccine such as FluMist when administered nasally has a greater potential to produce a broad immune response, including response to drifted strains, than the inactivated flu vaccines," said Robert B. Belshe, MD, director of the Center for Vaccine Development at Saint Louis University School of Medicine and the lead investigator for the pivotal clinical trial of FluMist. "This potentially important advantage over inactivated influenza vaccines needs to be further explored in clinical trials."

Each year the U.S. Public Health Service and the World Health Organization (WHO) select the three influenza strains that should be represented in all manufacturers' flu vaccines. Belshe said that in some years, including this year, the strains selected for the flu vaccine will be somewhat different than the strains of flu circulating in the community.

The maker of the vaccine, MedImmune Inc., is currently conducting additional studies with FluMist to confirm these findings.

The FDA has approved the use of FluMist to prevent influenza in healthy children, adolescents and adults ages 5 through 49. This is the first and only intranasal influenza vaccine in the United States.

"Delivering a flu vaccine via a nasal mist makes good clinical sense because influenza is an airborne virus that starts in the nose," Belshe said.

Influenza is the most common cause of acute respiratory illness requiring medical care in the U.S., often involving fever, chills, muscle weakness, cough, sore throat, nasal congestion, headache and general malaise. According to the Centers for Disease Control and Prevention and the American Lung Association, 20 to 50 million people are infected annually in the U.S., causing 70 million lost work days, 38 million lost school days, and 20,000 to 50,000 deaths per year (primarily in the elderly). The annual burden of the disease to society has been estimated at $15 billion.

Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first M.D. degree west of the Mississippi River. Saint Louis University School of Medicine is a pioneer in geriatric medicine, organ transplantation, chronic disease prevention, cardiovascular disease, neurosciences and vaccine research, among others. The School of Medicine trains physicians and biomedical scientists, conducts medical research, and provides health services on a local, national and international level.