Poliomyelitis in Oman: acute flaccid paralysis surveillance leading to early detection and rapid response to a type 3 outbreak

Abstract

Countries are increasingly requesting guidance on carrying out acute flaccid paralysis (AFP) surveillance, aimed at detecting and confirming all cases of acute paralytic poliomyelitis. The experience of Oman provides many lessons in this respect. AFP surveillance in Oman was established systematically. First, an epidemiologist was assigned to coordinate surveillance, and a laboratory for performing polio-virus isolation was identified. Next, operational guidelines for AFP surveillance were developed and widely promoted among health staff. The quality of the system has been monitored for more than 3 years with selected performance indicators. From January 1990 to April 1993, 49 AFP cases were reported, corresponding to an average annual rate of 2.1 AFP cases per 100,000 children aged less than 15 years. A total of 98% of the AFP cases were investigated within 48 hours of being reported; two stool samples were obtained from 94% of the cases. Following complete investigation, nearly a third of the reported AFP cases were classified as being clinically compatible with Guillain-Barré syndrome. Four AFP cases, all reported in 1991, were confirmed to be due to wild type 3 poliovirus. Because AFP surveillance detected these cases rapidly, Oman was able to carry out outbreak control measures promptly and more than 350,000 extra doses of oral poliovirus vaccine were delivered to children under 6 years of age.