Al-Dhahry S H, Koul R L, Al-Busaidy S M, Al-Awaidy S T, Al-Khusaiby S M, Suleman A J
Department of Microbiology & Immunology, College of Medicine, Sultan Qaboos University, PO Box 35, Al-Khodh, Muscat 123, Oman.
Acta Trop. 2001 Oct 22;80(2):125-30. doi: 10.1016/s0001-706x(01)00166-8.
Since 1988, the Sultanate of Oman has experienced three outbreaks of paralytic poliomyelitis. The last outbreak occurred in December 1993 and involved two children aged 10 months and 4 1/2 years. The children had received five and four doses, respectively, of trivalent oral polio vaccine (OPV) and lived in the same village. Serum neutralizing antibody tests suggested that paralytic polio in these children was due to poor antibody response to OPV. Wild poliovirus type 1 was isolated from both patients, as well as from seven of ten close contacts of the older child, and one of eight contacts of the younger child. All contacts had received three to six doses of OPV. Genomic sequence studies indicated that the virus isolates belonged to a genotypic group prevalent in southern and western Asia, but differed markedly from virus isolated during the 1988/89 outbreak, suggesting another importation of poliovirus. In response to the outbreak, supplementary immunization with OPV was given to children <6 years of age, initially in the affected district, and subsequently to children in the whole country. This study demonstrates that immunization with three to six doses of OPV did not prevent infection with wild poliovirus. In those children with sub-optimal response to OPV, infection resulted in paralytic poliomyelitis. The outbreak remained localized in one village, indicating that the outbreak control measures were effective.
自1988年以来，阿曼苏丹国经历了三次麻痹性脊髓灰质炎疫情。最后一次疫情发生在1993年12月，涉及两名儿童，年龄分别为10个月和4岁半。这两名儿童分别接种了五剂和四剂三价口服脊髓灰质炎疫苗（OPV），且居住在同一个村庄。血清中和抗体检测表明，这些儿童的麻痹性脊髓灰质炎是由于对OPV的抗体反应不佳所致。从两名患者以及年龄较大儿童的十名密切接触者中的七人、年龄较小儿童的八名接触者中的一人身上分离出了1型野生脊髓灰质炎病毒。所有接触者均接种了三至六剂OPV。基因组序列研究表明，病毒分离株属于在南亚和西亚流行的一个基因型组，但与1988/89年疫情期间分离出的病毒有明显差异，这表明脊髓灰质炎病毒再次传入。针对此次疫情，最初在受影响地区对6岁以下儿童进行了OPV补充免疫，随后在全国范围内开展。这项研究表明，接种三至六剂OPV并不能预防野生脊髓灰质炎病毒感染。在那些对OPV反应欠佳的儿童中，感染导致了麻痹性脊髓灰质炎。疫情仅局限于一个村庄，这表明疫情控制措施是有效的。
