University of Virginia Health System

Nasal Spray Vaccine Prevents Flu, Ear Infections

Child-friendly vaccine nasal spray means no more shots

The result is a major breakthrough in the battle to immunize children against influenza without fear of the pain of a shot, said Dr. Frederick Hayden, professor of pediatrics at U.Va. and one of the lead investigators in the study. Perhaps just as important, the vaccine prevented otitis media (ear infections) in the study children. We were surprised by the magnitude of the reduction in ear infections.

Of the 1,070 children who received the vaccine in the study, only one child developed an ear infection and fever, meaning the intranasal influenza vaccine provided 98 percent protection against influenza-associated otitis media.

Pediatric influenza vaccination drastically reduces the incidence of influenza-related disease, such as ear infections, that cost money and cause suffering in children, Hayden said.

Ear infections have been rising sharply in the number of reported cases since 1975. It is estimated that there will have been 30 million doctor visits last year for acute infections, which is a 300 percent increase in office visits since the mid-70's. It is the most common illness for which parents take their children to see a pediatrician. By age three, more than 80 percent of children have had at least one episode of acute otitis media and nearly 50 percent have had three or more episodes.

Ear infections are triggered by a virus, Hayden said. We think it starts by having a mild to severe respiratory infection, like the flu. The eustachian tube swells and traps fluid near the middle ear. This gives bacteria a chance to multiply and cause disease, so preventing the flu in turn prevents the ear infections.

The frequency of ear infections has led to a tendency to over-prescribe the antibiotics that treat them, Hayden continued. As a result, bacteria have become resistant to these medications, making them increasingly ineffective. If we reduce the incidence of otitis media, we should be able to prolong the use of antibiotics as efficient therapies.

Overall, the vaccine spray provided 93 percent protection against influenza in the tested population. Only 1 percent of the 1,070 children who received the vaccine developed culture-confirmed influenza during last year's flu season versus 18 percent of 532 children the same age who received the placebo.

The vaccine study enrolled 1,602 children from 15 months to 6 years old. Researchers targeted healthy young children because they experience the highest incidence of influenza and are a major source of its spread.

The new vaccine is made from a weakened influenza virus. While it cannot cause influenza, it is designed to stimulate antibodies in the nasal passage that protect against naturally acquired infection. Like the current licensed vaccine, the new nasal spray vaccine contains two strains of influenza A and one strain of influenza B.

The flu affects up to 50 million people a year in the United States. Epidemics usually occur between late fall and early spring. More than 20,000 people die from influenza and its complications each year. An estimated $4.6 billion is spent annually on direct medical costs related to influenza.

The study was co-sponsored by the National Institute of Allergy and Infectious Disease (NIAID), one of the National Institutes of Health (NIH), and Aviron (Nasdaq: AVIR), a biopharmaceutical company in Mountain View, Calif. The company has named the new product FluMist.

The research was conducted at NIAID-sponsored Vaccine and Treatment Evaluation Units (VTEUs) at Saint Louis University (the lead center), Baylor College of Medicine, Harbour-UCLA Research and Education Institute, the University of Rochester, Children's Hospital Medical Center in Cincinnati, and the University of Maryland at Baltimore, as well as four Aviron-supported sites, including Vanderbilt University in Nashville, Tenn., the University of Virginia, Charlottesville, Va., the University of Pittsburgh in Pittsburgh, Pa. and Bardstown, Ky.

The six VTEUs are part of a network of university-based sites funded by the NIAID to conduct research into new and improved vaccines against major childhood and adult diseases.

Scientists at the University of Michigan, NIH and Aviron developed the new vaccine.

May 13, 1998