To remain polio-free we must ensure the maintenance of our highly sensitive surveillance system, so that we can detect outbreaks early, and we must also sustain high levels of polio immunization through routine immunization.
In the early years of polio vaccine development, many studies were carried out to determine the protective levels of polio antibodies [ 18].
With the all-time low levels of polio in Egypt, India, Pakistan and Afghanistan, four of the six remaining endemic countries are on track to meet the end-2004 target for stopping polio – a date set by endemic country governments on 15 January at the signing of the "Geneva Declaration for the Eradication of Poliomyelitis".
With latest figures showing the Asian and north African regions at record low levels of polio (together reporting only 21 cases in 2004, compared to 94 this time last year), ministers of health of Afghanistan, Egypt, India, and Pakistan announced an accelerated strategy to "mop-up" each new virus.
In addition, immunization coverage appears higher in CGPP program areas compared to state averages, even though these areas have a level of intensity of polio eradication efforts greater than in the rest of the state.
The results of this study indicate that the cut-off level for polio antibodies is 0.075 IU/ml for Polio 1, 0.180 IU/ml for Polio 2 and 0.080 IU/ml for Polio 3. Neutralizing antibodies against poliovirus type 1, 2 and 3 were detected in 96.2%, 96.8% and 89.6% of samples, respectively.
A previous seroepidemiological study in Germany as well as this one revealed substantial regional variations of immunity levels to Polio 3 [ 10].
Despite the massive exodus of people from East-Europe during 1990's and the large outbreak which occurred in Albania in 1996, no imported cases have been reported in the latest period because of the good level of coverage for polio in these populations [ 28].
And, there is no evidence that routine immunization in CGPP areas was worse than performance at the state level despite increased intensity of polio eradication efforts in these areas.
