Effect of different vaccination schedules on excretion of oral poliovirus vaccine strains.

Inactivated poliovirus vaccine (IPV) is believed to induce significantly lower mucosal immunity than oral poliovirus vaccine (OPV). Most of the data supporting this were generated before enhanced IPV (eIPV) was introduced. Excretion of poliovirus by OPV recipients can be used to assess intestinal immunity. We studied polymerase chain reaction amplification of viral complementary DNA from the stool of children vaccinated with either OPV alone or eIPV. Of first-time OPV recipients, 92% excreted virus after 1 week, and 81% excreted virus after 3 weeks. Prior vaccination with OPV reduced the number to 22% and shortened the duration of virus excretion (to 5% after 3 weeks). Two doses of IPV reduced the number of poliovirus-positive 1-week samples (to 76%), the duration of shedding (to 37% at 3 weeks), and the quantity of excreted virus. This suggests that IPV-vaccinated communities are partially protected from the spread of poliovirus. Further enhancement of IPV potency may lead to even higher levels of mucosal immunity.

[A comparison of the diagnostic value of the virus neutralization reaction and of indirect immunoenzyme analysis using monoclonal antibodies for the intratype differentiation of vaccinal and virulent poliovirus strains]. / Porivniannia diahnostychnoï tsinnosti reaktsiï virusneitralizatsiï ta nepriamoho imunofermentnoho analizu z vykorystanniam monoklonal'nykh antytil dlia vnutrishn'otypovoï dyfereentsiatsiï vaktsynnykh ta virulentnykh shtamiv poliovirusiv.

A comparative evaluation was carried out of potentialities of the practical use of the virus neutralization reaction (VNR) and indirect immunoenzymatic analysis (IIEA) relying on the monoclonal antibodies (MKAB) for intratype differentiation of polioviruses. It has been proved that in each of the reactions MKAB can interact with different epitopes on the surface of virions. This brings about an unequal degree of activity and specificity of similar antibodies in the two serologic reactions. In VNR monoclonal antibodies "work" in a more specific manner than they do in IIEA. Therefore this test is still more suitable for clinical use in intratype differentiation of polioviruses.

Preventive strategies against poliomyelitis.

Successful poliomyelitis prevention depends upon the epidemiological characteristics of the infection and the immune status of the population in the area. Presently available polio vaccines may prove very useful for progress with polio control, provided the prevention programme has been adequately chosen and the limitations of the vaccine used have been taken into consideration. In the present and near future, polio prevention should aim at the containment and local elimination of the paralytic disease, which can be obtained with either OPV or E-IPV. The vaccine-associated disease remains an unsolved issue in an OPV programme. The association of OPV and E-IPV offers a clear advantage over the immunization with a single vaccine, particularly with OPV alone. Global eradication of polio, possible in principle, will be difficult to achieve by the year 2000, because of the present global dimensions of polio infection and the unequal environmental development of the world.

Eradication of poliomyelitis in the United States. II. Experience with killed poliovirus vaccine.

Killed poliovirus vaccine was the only poliomyelitis vaccine available in the United States from 1954 to 1962. During that time, the incidence of poliomyelitis among non-vaccinated individuals decreased by 90%, an indication that the circulation of wild poliovirus had been reduced ("herd effect"). The rate of decline of wild poliovirus disease, which resulted from use of killed vaccine, did not change after oral, live poliovirus vaccine was introduced in 1962. Neither mass immunization campaigns nor use of an orally administered vaccine has increased rates of poliomyelitis immunization. Outbreaks of poliomyelitis can occur in susceptible subgroups in otherwise well vaccinated populations; therefore, the degree of population protection is best evaluated in terms of the number of susceptible individuals and their opportunities for contact with each other rather than in terms of the percentage of the total population vaccinated. Eradication of poliomyelitis and elimination of poliovirus from large populations are possible with use of killed poliovirus vaccine.

Eradication of poliomyelitis in the United States. III. Poliovaccines--practical considerations.

Practical considerations for the choice of poliomyelitis vaccine in the United States are discussed. Both killed and live poliovirus vaccines protect against paralysis. They provide equivalent duration of immunity in individuals, equivalent protection against spread of poliovirus in communities, and equally rapid protection during epidemic outbreaks of poliomyelitis. The principal differences between these vaccines are the transmission of live vaccine viruses from recipieits to their contacts and the occurrence of occasional cases of paralytic poliomyelitis associated with use of live poliovirus vaccine. Risks and benefits of "spreading immunity" by person-to-person transmission of live vaccine viruses are presented. Suggestions for reducing the incidence of live virus vaccine-associated disease are discussed. The level of protection against poliomyelitis that has been achieved in the general population of the United States has resulted in the virtual eradication of disease due to wild polioviruses. Routine use of killed poliovirus vaccine may eradicate all domestically arising poliomyelitis, both vaccine-associated and wild poliovirus disease, and may eliminate poliovirus from the United States.