If the percentage of the population in a vaccinated community is below this threshold number, the disease will begin to spread more freely and may generate an outbreak of this disease within the community.
如果社区里接种过疫苗的人口百分比 低于这个阈值的数字 那么这个疾病就会很容易传播 且这个社区可能会爆发这种疾病