[Risk of introduction and spread of polioviruses in closed-type child-care facilities].

AIM

Compare frequency of isolation of polioviruses in children living in closed-type facilities (orphanages) before and after the change in poliomyelitis vaccination scheme.

MATERIALS AND METHODS

Feces samples of 207 children from 5 orphanages during immunization with oral poliomyelitis vaccine (OPV) and of 259 children from 4 orphanages during vaccination with inactivated poliomyelitis vaccine (IPV) were studied. Isolation and identification of polioviruses was carried out according to WHO recommendations.

RESULTS

In orphanages, where children were immunized with the oral vaccines, 21 polioviruses were isolated. In orphanages, where only inactivated vaccine was used, 10 polioviruses were isolated, the presence of polioviruses in these facilities is associated with their introduction from the outside. The percentage of poliovirus detection in children immunized with OPV was shown to be 16.9 ± 3.4% and was significantly higher than in children vaccinated with IPV (6.1 ± 1.9%). Polioviruses isolated from children immunized with OPV belonged to serotypes 1, 2 and 3 in 19.0, 14.3 and 66.7% of cases, respectively. Polioviruses detected in children immunized with IPV belonged to serotypes 1, 2 and 3 in 30, 40 and 30% of cases, respectively. All the isolated polioviruses turned out to be Sabin vaccine strains.

CONCLUSION

Implementation of strict prophylaxis measures in orphanages is necessary in order to prevent the possibility of introduction, transmission and circulation of polioviruses. Improvement of control in children from closed-type facilities will ensure maintenance of Russian Federation status as the country free of poliomyelitis.