Particularly risky experiments are underway, he says, yet WHO experts hae agreed that no alid reason exists to retain smallpox irus stocks for DNA sequencing, diagnostic tests, or accine deelopment.

• 极其危险的试验正在进行；他说；但WHO的专家们一致认为；没有为DNA测序；诊断试验或疫苗研制而保留天花病毒储存的正当理由.