Behavior of Sabin Type 1 Attenuated Poliovirus in an Infant Population Infected With Echo 14 Virus

Twenty-five babies fully susceptible to poliovirus, and dwelling in an infant home, were fed Sabin LSc2ab Type 1 attenuated poliovirus. Although 40% of the infant population was infected concurrently with ECHO 14 virus, little effect was noted upon either acquisition of infection with attenuated poliovirus or the development of immunity to it. Sixty-six per cent of the unvaccinated infants who were studied became infected with poliovirus, and some were noted to excrete it for as long as 2 months. Poliovirus persisted in the institution for at least 3 months following the last feeding of vaccine. No illness could be attributed to the ECHO 14 virus, and little immunologic response was demonstrated to this virus in the study population.