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In this study,we attenuated a Chinese QX-like nephropathogenic infectious bronchitis virus (IBV) strain.YX10,by passaging through fertilized chicken eggs.The 90th passage strain (YX10p90) was selected as the live-attenuated vaccine candidate strain.YX10p90 was found to be safe in 14-day-old specific pathogen free chickens without induction of morbidity or mortality.YX10p90 provided nearly complete protection against QX-like (CH 1 genotype) strains and partial protection against other two major Chinese genotype strains.