Polio is a disease that generally impacts children under the age of five who have not been vaccinated against it. Polio can cause permanent paralysis and death. There are two types of polio vaccines; the OPV (oral polio vaccine) and the IPV (inactivated polio vaccine). Although the number of wild polio cases has dramatically decreased due to regular vaccinations, the number of cases resulting in paralysis linked to the OPV is currently higher than the amount of paralysis cases caused by the wild polio virus itself. I find this very concerning!
As stated in a Cochrane article, as of 2016, the Word Health Organization has recommended that children should have has at least one dose of the IPV before the OPV. This will hopefully lessen the chances of developing paralysis as a result of the oral polio vaccine. The OPV has the ability to cause paralysis because it is a live attenuated vaccine as opposed to carrying an inactivated virus form, like the IPV. If given a dose of IPV first, their body will develop antibodies as protection against polio without being exposed to the live virus. The good news is, when these vaccines are given in the IPV-OPV order, chances of paralysis linked to the OPV is lessened by up to 100%.
A complete shift from the OPV to the safer IPV was perviously inhibited due to cost constraints. However, Dr. Andrew Kreppel studied the effectiveness of a new, less expensive inactivated polio vaccine. In his study, Kreppel had a participant pool of 1115 healthy, polio-unimmunized infants 60-90 days old. He was able to determine that the new sIPV is non-inferior when compared to the more expensive IPV. This was determined by measures of seroconversion rates along with geometric mean titers. I think these results are very promising and hopefully will soon be able to limits risks of paralysis associated with polio immunizations.
Kinsey's Blog 