European journal of epidemiology
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A report is presented about studies on poliovirus type 3 isolates from vaccine-associated cases or contacts of cases of paralytic poliomyelitis, observed over a period of 30 years in East Germany (former GDR). In the viral isolates, some mutations were found in comparison to the Sabin vaccine type 3 strain, distributed over the whole genome. ⋯ In five isolates, intertypic recombination between Sabin type 3 and Sabin type 1 vaccine strain occurred. Primary and secondary structures were analysed for the recombination sites.