The intervention reduced the presence of adenovirus [ odds ratio ( OR ) 2.4 , 95 % confidence interval ( CI ) 1.1-5 .0 ] , rhinovirus ( OR 5.3 , 95 % CI 2.3-12 .4 ) and respiratory syncytial virus ( OR 4.1 , 95 % CI 1.5-11 .2 ) compared with the control group , but the intervention had no effect on sickness absence or disease patterns in the nurseries .