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VOL. 71 (2), 321-339, 2005 HISTORY AND FUTURE OF POLIOVACCINATION...

immunization. The strategy is similar to that used for smallpox
eradication in 1977.

The strategy developed by WHO and its partners (Rotary,
UNICEF) to eradicate polio has 4 components:

(1) High routine infant immunization with OPV. OPV is one
of the six antigens provided by the national routine
immunization programme during the first year of life.
Routine coverage of at least 90% with three doses of OPV is
the foundation for establishing the level of population
immunity needed to eradicate polio.

(2) Supplemental mass immunization (National Immunization
days). In order to ensure that all children have been
adequately immunized with OPV and interrupt the
circulation of wild poliovirus, it is necessary to conduct
supplemental immunization campaigns.

(3) Epidemiological and laboratory surveillance for Acute
Flaccid Paralysis. A sensitive surveillance system for acute
flaccid paralysis is necessary to identify paths of continuing
transmission of wild poliovirus and to provide evidence to
allow for the certification of polio-free status and subsequent
cessation of immunization.

(4) «Mopping-up» immunization. «Mopping-up» immunization
activities are most important in the later stages of the
eradication effort, when areas that are at high risk based on
continued circulation of the wild poliovirus, can be targeted.
During this phase, OPV is administered in a house-to-house
campaign (2).

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