在这一周期间，每一个参加国实施活动，向主要目标群体提供信息和使它们参与，并将其国家免疫方面的严重挑战作为目标。

During the Week, each participating country implements activities to inform and engage key target groups, and to target critical challenges as regards immunization in their country.

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群体生态系统的广泛活动很大程度上是自发的，由参与者的共同热情所驱动，但没有任何明确定义的“中心”来组织这些努力。

Pack ecosystems represent broad initiatives that are largely spontaneous, driven by a common passion among a group of participants without any clearly defined "center" to organize the efforts.

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像Facebook这样的网站，穿梭于实体世界和虚拟世界之间，鼓励年轻人加入群体、参与活动，将他们引入到新的实体现实中。

Sites like Facebook hop between the physical and the virtual, encouraging young people to join groups and events that introduce them to new physical realities.

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