“When known importations have occurred in Canada, in the United States . . . in Sweden, and in The Netherlands . . . cases of polio have . . . all occurred in either unvaccinated or inadequately vaccinated groups. . . . Virus has not spread to the vaccinated population, regardless of whether OPV or IPV has been used. . . . A well-immunized population with IPV clearly seems to be able to withstand significant disease. . . . If you have an all IPV policy, you don't have any vaccine-associated disease. . . . [A] serious question has to be asked whether you can continue to afford to have eight to ten paralytic cases of polio in the United States because of an OPV policy.”

From a presentation by Ronald Gold in advocacy of an IPV vaccination strategy, CDC-sponsored polio vaccine workshop, June 8, 1995.

Pasteur Mérieux is currently the only manufacturer of IPV and would monopolize the market until IPVs in development by other manufacturers are licensed. The amount of vaccine immediately available could not meet the demand in the United States if the schedule were immediately changed from OPV to IPV. The price per dose of IPV is greater than that for OPV; however, some savings are achieved because wastage per vial may be reduced. The price of IPV will be reduced as more manufacturers enter the market, and as the volume of sales increases, the price could become comparable to that of OPV.

SEQUENTIAL SCHEDULE FOR IPV and OPV7

Public Health Experience

When OPV was introduced in the United States in 1961–1964, most children who received the vaccine had already received some doses of IPV. Cases of VAPP have been reported rarely in OPV recipients who previously received IPV.

In Canada between 1965 and 1988, the various provinces used IPV, OPV, or a sequential series of IPV and OPV. Surveillance for vaccine-associated

7  

The material in this section is adapted from a presentation by John Modlin and comments by other workshop speakers or participants.



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