initial transmission

例句：

1. 1. The initial transmission of the virus is a major concern for public health officials.
   病毒的初始传播是公共卫生官员们的主要关切。
2. 2. In the early stages of the pandemic, effective initial transmission prevention measures are crucial.
   在疫情初期，有效的初始传播预防措施至关重要。
3. 3. Researchers have been exploring new methods to reduce initial transmission rates and improve vaccine efficacy.
   研究人员一直在探索新的方法和策略，以降低初始传播率并提高疫苗效力。