COMING YOUR WAY:
OPV vs. IPV-- A Complex Choice
Charles Grose, MD, Professor and Director of Infectious Disease Control,
Department of Pediatrics, The University of Iowa
Summer 1997

Two of the most famous names in American virology are Jonas Salk and Albert Sabin. Jonas Salk produced inactivated poliovirus vaccine (IPV) and Albert Sabin produced live attenuated [oral] poliovirus vaccine (OPV). Their efforts to produce a vaccine began in the 1940s.

Today, health care providers are heatedly debating the merits of IPV versus OPV. IPV was actually the first poliovaccine approved in the US, and its use resulted in a marked decline in the incidence of poliomyelitis. Then a dramatic and terrible mistake occurred in a plant which manufactured IPV. The vaccine was not completely inactivated, and scores of immunized children developed paralytic poliomyelitis. Shortly thereafter the US public health service switched to OPV, originally developed by Sabin and first tested in the USSR.

The widespread use of OPV, one of the most successful vaccines ever developed, has led to the near elimination of paralytic poliomyelitis in the US, Canada, and more recently in much of Central and South America. The vaccination mimics the natural disease, so there is a lifelong immune response after the initial vaccine series.

Yet OPV presents a threat. It can revert to a paralytic virus that can infect an immunocompromised child or a non-immunized adult. In the US, about 5 to 20 children develop paralytic polio each year following vaccination with OPV. Non-immunized adults, most often parents, can pick up the virus from an infant who has been given the OPV vaccine.

After years of intense debate, the public health service recently made the decision, albeit not unanimously, to recommend that infants in the US be immunized with IPV in the first year, because by the end of the first year most immune deficiencies will have been diagnosed. The booster can then be OPV. Non-immunized parents of infants can be given IPV at the same time their infants are immunized. At the University of Iowa Hospitals and Clinics, the preferred protocol calls for infants to receive IPV during the first year of life and OPV thereafter in childhood.

For immunocompromised infants, the use of IPV is most appropriate. With the use of IPV, children with immune deficiencies will continue to need IPV boosters, most likely through adulthood (OPV requires no booster in adulthood).

In the future, a new combination vaccine may provide yet another alternative. Attempts are being made to develop a 5-in-1 immunization for pertussis, diphtheria, tetanus, haemophilus, and polio. But it won't be available soon.