Each winter, influenza causes significant illness in all age groups, according to the article. The U.S. Food and Drug Administration recently approved an influenza virus vaccine (cold-adapted trivalent influenza virus vaccine, or CAIV-T) administered in the form of a nasal spray for use in healthy children and adults aged 5 through 49 years. Previous studies have shown that the nasal spray was successful in preventing influenza A (H3N2) and B infections in children 15 months old to about 6 years old, and was effective in preventing certain strains of the influenza virus from infecting adults. However, the ability of CAIV-T to prevent natural influenza A (H1N1) infection is unknown.
Manjusha J. Gaglani, M.B.B.S., from the Scott & White Memorial Hospital and Clinic, Temple, Tex., and colleagues assessed the effectiveness of CAIV-T in healthy children during the 2000-2001 influenza A (H1N1) epidemic.
The incidence of respiratory infections that resulted in a medical visit among 3,794 healthy children aged 1.5 to 18 years who received the CAIV-T vaccine at least once in 1998, 1999 and/or 2000 was compared with the incidence among 9,325 healthy non-recipient children and adolescents in the same communities, and 16,264 in two other communities.
The researchers found, "Significant direct effectiveness of CAIV-T for prevention of [acute respiratory illness] in all age groups and in all children vaccinated in 2000 was observed during the entire influenza A and B epidemic. Direct effectiveness in all children and children aged 1.5 to 4 and 5 to 9 years during the six weeks when influenza A (H1N1) viruses predominated documented effectiveness of CAIV-T against natural influenza A (H1N1) infection for the first time," write the authors.
(Arch Pediatr Adolesc Med. 2004;158:65-73. Available post-embargo at archpediatrics.com)
Editor's Note: This study was supported by a grant from the National Institutes of Health, Bethesda, Md., and MedImmune, Inc., Mountain View, Calif., which provided the investigational intranasal influenza vaccine.
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