A new nasal spray vaccine is being studied that may prove to be an effective way of vaccinating children against influenza. A recent study presented at the 1998 Society for Pediatric Research Annual Meeting shows that children given the new vaccine developed anti-influenza antibodies in their nasal secretions.
Influenza epidemics occur yearly and are an important cause of wintertime respiratory illness throughout the world. Infection rates are highest in young children, often exceeding 40%. A current vaccine is given by intramuscular injection and is not routinely administered to healthy children.
Vaccines work by stimulating the body's immune system to make antibodies against the infectious agent. It is unknown what types of antibodies are most important in protecting against influenza.
"Traditionally, antibodies measured in the blood are used as a marker for protection. However, there is some evidence that antibodies in the nose, where the virus first enters the body, are more important for protection," said Dr. Thomas Boyce, fellow in Pediatric Infectious Diseases at Vanderbilt University Medical Center.
Knowing which types of antibodies the intranasal influenza vaccine stimulates will be important in refining future versions of the vaccine.
"In our study we sought to determine whether the intranasal influenza vaccine causes the production of local antibodies in the nose (mucosal IgA antibodies)," said Boyce.
Researchers at Vanderbilt obtained nasal washes on 19 children before and after they had been given either the intranasal influenza vaccine or a placebo. They then tested the nasal washes for mucosal IgA antibodies to the three different influenza strains contained in the vaccine. The majority of children who had been given the vaccine developed mucosal IgA antibodies to all three influenza strains, whereas most of the children who received placebo did not.
"The nasal spray vaccine appears to stimulate the production of local antibodies in the nose, where influenza enters the body," said Boyce. "We hope these antibodies will stop the virus in its tracks, before it has a chance to spread to the rest of the respiratory system."
Further studies are under way to determine if the presence of these local antibodies correlates with protection from infection with the influenza virus.
The above story is based on materials provided by Vanderbilt University Medical Center. Note: Materials may be edited for content and length.
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