The authors note that inactivated, trivalent, injectable influenza vaccine (injectable vaccine) is the only formulation approved for use in high-risk children, owing in part to concerns that live attenuated influenza vaccine (given nasally) might worsen asthma symptoms in asthmatics. This paper reports the results of an efficacy and safety trial of a reformulated live attenuated vaccine (live vaccine).
Subjects were European children aged 6-17 years with asthma enrolled during the 2002-2003 influenza season. The study excluded children with many other chronic diseases and children who were immune compromised. For 15 days after vaccination (1:1 randomization to live or injectable vaccine), parents recorded daily asthma symptom scores and peak expiratory flow measurements. In addition, the parents recorded nocturnal symptoms and asthma medication use. After the 15 days of parental log completion, investigators contacted subjects weekly to determine if they required revisit for symptoms. Any subject who developed fever or upper or lower respiratory illness was seen for office visit and nasal swab for influenza culture. The subjects were also monitored for side effects and other unscheduled medical visits. The study enrolled 2229 subjects, with 1114 receiving live vaccine.