Excretion of vaccine polioviruses by the children From closed institutions

Investigation of 198 healthy vaccinees from closed institutions resulted in isolation of37 vaccine polioviruses. In the orphanages where among other children there lived children born to HIV-positive mothers the frequency of isolation of polioviruses was higher than in other institutions. In these orphanages the period of excretion of polioviruses after vaccination was the longest. The RFLP analysis showed that 41% of the studied strains were the intertypic recombinant strains. According to the sequence analysis 29% of the studied strains had a certain number of nucleotide substitutions in the VP3-VP1 genomic region. The study revealed a correlation between the dynamics of the excretion of polioviruses after vaccination and the kinetics of the appearance of intertypic recombinants. On the latest days after vaccination all the excreted polioviruses were the recombinant strains.