Poliovirus vaccine strains will continue to circulate long after wild strains have been eradicated.

States that poliovirus vaccine strains will continue to circulate long after wild strains have been eradicated. Differences between the poliovirus and smallpox strains; Eradication programs for each virus; Varieties of smallpox; Continued use of oral polio vaccines in developing countries; Need to make inactivated polio vaccine available at an affordable price in all countries; Issue of polio and poliovirus eradication.