A controlled trial with inactivated poliovaccine.

A trail with inactivated polio vaccine (IPV) was carried out, aiming at the earliest possible vaccination of young infants from rural settlements, before their exposure to type 1 wild poliovirus, highly prevalent in the environment. One hundred and fifteen infants were primed at the age of 2 and 3 1/2 months with the quadruple antigen DPT-polio. When 10 months old, 61 were boosted with the same antigen, and 54 with TOPV associated with DTP. Another 53 babies fed with TOPV at 2, 4, 6 and 12 months were used as a control. One dose of IPV produced antibody to polio type 1 in 83% of babies. With two doses of IPV a 100% response was obtained. Six months after the second dose, a small decrease in the percentage of infants wih detectable antibody to type 1 was observed, but at one month after the booster a highly significant anamnestic response was achieved. The results with IPV compared favorably with the immune response of infants given TOPV. Details on the results of the field trial will be presented, and field implementations of IPV will be discussed.