Background: Despite their potential for increased morbidity, 75% to 90% of asthmatic children do not receive influenza vaccination. Live attenuated influenza vaccine (LAIV), a cold-adapted, temperature-sensitive, trivalent influenza vaccine, is approved for prevention of influenza in healthy children 5 to 19 years of age. LAIV has been studied in only a small number of children with asthma.
Methods: Children 6 to 17 years of age, with a clinical diagnosis of asthma, received a single dose of either intranasal CAIV-T (an investigational refrigerator-stable formulation of LAIV; n = 1114) or injectable trivalent inactivated influenza vaccine (TIV; n = 1115) in this randomized, open-label study during the 2002–2003 influenza season. Participants were followed up for culture-confirmed influenza illness, respiratory outcome, and safety.
Results: The incidence of community-acquired culture-confirmed influenza illness was 4.1% (CAIV-T) versus 6.2% (TIV), demonstrating a significantly greater relative efficacy of CAIV-T versus TIV of 34.7% (90% confidence interval [CI] 9.4%–53.2%; 95% CI = 3.9%–56.0%). There were no significant differences between treatment groups in the incidence of asthma exacerbations, mean peak expiratory flow rate findings, asthma symptom scores, or nighttime awakening scores. The incidence of runny nose/nasal congestion was higher for CAIV-T (66.2%) than TIV (52.5%) recipients. Approximately 70% of TIV recipients reported injection site reactions.
Conclusions: CAIV-T was well tolerated in children and adolescents with asthma. There was no evidence of a significant increase in adverse pulmonary outcomes for CAIV-T compared with TIV. CAIV-T had a significantly greater relative efficacy of 35% compared with TIV in this high-risk population.
From the *Northfield Health Centre, Birmingham, United Kingdom; †Universita di Genova Istituto di Igiene e Medicina Preventiva Dipartimento di Scienze della Salute, Genova, Italy; ‡Universitätsklinikum Berlin Charité Pneumologie und Immunologie, Berlin, Germany; §Jorvi Hospital, Espoo, Finland; ¶Shaare Zedek Medical Center, Jerusalem, affiliated to the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; ∥General Hospital of Arta Paediatric department, Arta, Greece; #Stavanger University Hospital, Stavanger, Norway; **Hospital Severo Ochoa de Leganes Servicio de Pediatria, Leganes, Spain; ††Private practice, Brussels, Belgium; ‡‡Centro Hospitalar de V.N. de Gaia Consulta externa de Alergologia Pediatrica, Vila Nova de Gaia, Portugal; §§University Children's Hospital, Basel, Switzerland; ¶¶Wyeth Vaccines Research, Louvain-la-Neuve, Belgium; ##Wyeth Vaccines Research, Pearl River, NY.
Accepted for publication July 14, 2006.
Sources of support: This study was funded by MedImmune and Wyeth Research.
Address for correspondence: William C. Gruber, MD, Wyeth Research, 401 N. Middletown Road, Pearl River, NY 10965. E-mail: email@example.com.