活病毒口服小兒麻痺疫苗(OPV)被用於臺灣地區小兒麻痺根除計畫已有相當長的歷史。由最不具熱安定性之小兒麻痺病毒製成的OPV，只有儲存在攝氏零下20度或更低的溫度中才能維持其安定性。本研究之目的為評估臺灣地區疫苗儲運cold chain系統是否具備維持小兒麻痺疫苗效價的能力。我們自民國86年9月至87年2月在臺灣各縣（含直轄市）市中隨機選擇衛生所、衛生室及合約醫院進行疫苗抽樣及效價試驗。從試驗結果中發現，所有疫苗檢體之第一型病毒效價皆符合我國衛生署及世界衛生組織的相關規定，此外除了少數個案外，絕大部份的第二與第三型病毒方可維持其效價。造成第二型病毒效價降低的原因可能與儲存時小兒麻痺疫苗是否處於溶解狀態有關，至於造成第三型病毒效價降低的原因仍不清楚，但上述第二與第三型病毒活性降低現象可能與儲存疫苗之冷凍櫃╱冰箱效率不佳有關。本研究的結果顯示臺灣地區所使用的cold chain系統已能提供活病毒口服小兒麻痺疫苗適當的儲存環境。

　　　　　The live attenuated oral poliovirus vaccine (OPV) has been used for thepoliomyelitis erad-ication program in Taiwan for a long time. Since it ismanufactured from a highly thermola-bile vaccine strain of poliovirus, it shouldbe stored under the recommended temperature of -20℃ or below. This studyinvestigated and evaluated the efficiency of the cold chain system for maintainingthe polio vaccine potency in Taiwan. We selected several health stations andlocal hospitals/pediatric offices in each County/City of Taiwan to take the OPVsamples and test their potency from Nov. 1997 to Feb. 1998. Our results showedthat the type-1 poliovirus of all OPV samples met the requirements for thepotency test, showing titers were higher than the criteria of the WHO and theROC (Taiwan) national standard. The type-2 and -3 polioviruses in most of theOPV samples showed titers higher than the criteria, with the exception of a fewsamples. We found that the degradation of type-2 poliovirus was associated withthe thawed samples, which were stored at temperatures not low enough. The factorthat caused the degradation of the type-3 poliovirus was unclear so far.Nevertheless, the results of this study indicated that the cold chain systemused in Taiwan was generally satisfactory for the OPV storage.