Emerging polio-free zone--southern Africa, 1990-1994.

A key component of the global strategy to eradicate poliomyelitis by the year 2000 is surveillance for all cases of acute flaccid paralysis (AFP), ensuring the detection of cases of paralytic polio. During the 1990s, most of the countries of southern Africa (Table 1) have reported high (i.e., 70%-90%) levels of vaccination coverage among children aged < 1 year with three doses of oral poliovirus vaccine (OPV3). In addition, with the exception of Namibia, all of these countries have reported very low or zero incidence of polio (Table 1, Figure 1). To determine whether the low number of reported polio cases reflects the true incidence or underreporting, during 1992 and 1993 assessments of polio incidence and the quality of surveillance of suspected polio were conducted by teams consisting of national health officials, World Health Organization (WHO) staff and consultants, and representatives from Rotary International, using a standard protocol (1). This report summarizes the findings of assessments in Botswana, Lesotho, Malawi, South Africa, Swaziland, and Zimbabwe.