Trends in the risk of U.S. polio outbreaks and poliovirus vaccine availability for response
by Kimberly M. Thompson, Gregory S. Wallace, Radboud J. Duintjer Tebbens, Philip J. Smith, Albert E. Barskey, Mark A. Pallansch, Kathleen M. Gallagher, James P. Alexander, Gregory L. Armstrong, Stephen L. Cochi, and Steven G. F. Wassilk, Public Health Reports 2012;127:23-37. PDF

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What are the study’s main findings?
What are the study’s main recommendations?
Background on polio

What are the study’s main findings?

• Although the risk of poliovirus introduction remains real, widespread transmission of polioviruses appears unlikely in the U.S. given high routine coverage.
• In some communities, clusters of un- or underimmunized children might create pockets of susceptibility that could potentially lead to one or more paralytic polio cases following an introduction of a live poliovirus.
• After 10 years of exclusive reliance on inactivated poliovirus vaccine (IPV), the U.S. population includes a declining proportion of individuals with mucosal immunity (i.e., immunity induced by infection with a live poliovirus) and population immunity no longer gets boosted from circulation of live polioviruses.
• The shift toward combination vaccine utilization, with limited age indications for use, and other current trends (e.g., the decreasing proportion of the population with immunity induced by live polioviruses and accumulation and aging of individuals with personal belief exemptions) might increase the vulnerability to poliovirus reintroduction at the same time that the ability to respond may decrease.
• The U.S. poliovirus vaccine stockpile remains an important resource that may potentially be needed in the future to respond to an outbreak if a live poliovirus gets imported into a subpopulation with low vaccination coverage.
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• Maintain the stockpile for poliovirus vaccines to enable response to an outbreak caused by an imported live poliovirus, and carefully monitor trends related to the susceptibility of the population and the availability of appropriate vaccines for use with different age groups for outbreak response
• Explore the potential needs and demands for poliovirus vaccine from high-risk subpopulations (e.g., clusters of religious objectors and individuals with personal belief exemptions) in more depth to identify potential strategies to close existing immunity gaps and/or develop appropriate targeted outbreak response plans and resources.
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