Efficacy and safety of a live attenuated, cold-adapted influenza vaccine, trivalent against culture-confirmed influenza in young children in Asia.
BACKGROUND
This study was designed to evaluate the efficacy and safety of cold-adapted influenza vaccine, trivalent (CAIV-T) against culture-confirmed influenza in children 12 to <36 months of age during 2 consecutive influenza seasons at multiple sites in Asia.


METHODS
In year 1, 3174 children 12 to <36 months of age were randomized to receive 2 doses of CAIV-T (n = 1900) or placebo (n = 1274) intranasally > or =28 days apart. In year 2, 2947 subjects were rerandomized to receive 1 dose of CAIV-T or placebo.


RESULTS
Mean age at enrollment was 23.5 +/- 7.4 months. In year 1, efficacy of CAIV-T compared with placebo was 72.9% [95% confidence interval (CI): 62.8-80.5%] against antigenically similar influenza subtypes, and 70.1% (95% CI: 60.9-77.3%) against any strain. In year 2, revaccination with CAIV-T demonstrated significant efficacy against antigenically similar (84.3%; 95% CI: 70.1-92.4%) and any (64.2%; 95% CI: 44.2-77.3%) influenza strains. In year 1, fever, runny nose/nasal congestion, decreased activity and appetite, and use of fever medication were more frequent with CAIV-T after dose 1. Runny nose/nasal congestion after dose 2 (year 1) and dose 3 (year 2) and use of fever medication after dose 3 (year 2) were the only other events reported significantly more frequently in CAIV-T recipients.


CONCLUSIONS
CAIV-T was well tolerated and effective in preventing culture-confirmed influenza illness over multiple and complex influenza seasons in young children in Asia.
Tam
John S
JS
Department of Microbiology and Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong. tamj1@wyeth.com
Capeding
Maria Rosario Z
MR
Lum
Lucy Chai See
LC
Chotpitayasunondh
Tawee
T
Jiang
Zaifang
Z
Huang
Li-Min
LM
Lee
Bee Wah
BW
Qian
Yuan
Y
Samakoses
Rudiwilai
R
Lolekha
Somsak
S
Rajamohanan
K Pillai
KP
Narayanan
S Noel
SN
Kirubakaran
Chellam
C
Rappaport
Ruth
R
Razmpour
Ahmad
A
Gruber
William C
WC
Forrest
Bruce D
BD
D000222:Adaptation, Physiological; D001208:Asia / Q000453:epidemiology; D002675:Child, Preschool; D003080:Cold Temperature; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects* / Q000276:immunology*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D009975:Orthomyxoviridae / Q000276:immunology* / Q000502:physiology; D014613:Vaccines, Attenuated / Q000009:adverse effects / Q000276:immunology*
D007252:Influenza Vaccines; D014613:Vaccines, Attenuated