Too few children had been immunized before day 60 in the CDC studies to assess adequately the hypothesis of a lower relative risk in younger infants.

• 但是在CDC的研究中,接种轮状病毒疫苗的小于60天的儿童人数太少,不足以评估小龄婴儿发生肠套叠相对危险性较低的假设。