1.A: Oral polio vaccine (OPV) contains a weakened version of poliovirus, activating an immune response in the body.
答：口服脊髓灰质炎疫苗（OPV）包含一种减毒脊髓灰质炎病毒，能在体内引发免疫反应。
2.The small risk of VDPVs pales in significance to the tremendous public health benefits associated with OPV.
从重要意义上来看，VDPV带来的微小风险与口服脊髓灰质炎疫苗产生的巨大公共卫生相关益处相比黯然失色。
3.The OPV also reports that 221 prisoners were murdered in the first six months of this year alone.
OPV还称，仅今年的前六个月，就有221名囚犯被谋杀。
4.Over the past 10 years, more than 10 billion doses of OPV have been administered to more than 2. 5 billion children.
过去十年中，共有25亿多儿童使用了超过100亿份口服脊髓灰质炎疫苗。
5.National Immunization Days (NIDs) will be conducted in the country on 18-20 July, using bivalent OPV (containing type 1 & 3 serotypes).
使用双价口服脊髓灰质炎疫苗的（包含1型和3型血清型）国家免疫接种日（NIDs）将于7月18-20日在该国开展。
6.Evaluation of OPV Supplementary Immunization Effect for Maintaining Polio-free Status in Hebei Province
河北省为保持无脊髓灰质炎实施的强化免疫效果评价
7.high infant immunization coverage with four doses of oral poliovirus vaccine (OPV) in the first year of life;
婴儿出生头一年服用四剂口服脊灰病毒疫苗（OPV），达到高免疫覆盖率；