Table 1.

Demographic characteristics of infants in the first population

Characteristic	RSV-positive	RSV-negative
Number (n)	370	305
Males [n (%)]	205 (55.4)	175 (57.4)
Breastfed [n (%)]	306 (82.7)	239 (78.4)
Smokers at home [n (%)]	216 (58.4)	166 (54.4)
Day care [n (%)]	13 (3.5)	17 (5.6)
Low socioeconomic status [n (%)]	255 (68.9)	244 (80.0)
Median sibs <14 yr (n)	3	3
Median age (mo)	4.0 ± 2.0	4.8 ± 1.9