Managing population immunity to reduce or eliminate the risks of circulation following the importation of polioviruses. Issue 13 (24th March 2015)

• Record Type: Journal Article
• Authors: Thompson, Kimberly M.; Kalkowska, Dominika A.; Duintjer Tebbens, Radboud J.
• Is Part Of: Vaccine. Volume 33:Issue 13(2015)
• Page Start: 1568
• Page End: 1577
• Publication Date: 2015-03-24
• Subjects: Polio -- Eradication -- Population immunity -- Vaccine; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2015.02.013
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: Countries continue to increasingly adopt inactivated poliovirus vaccine (IPV). Using IPV only, even with high coverage, may not prevent live poliovirus transmission. A 2013 wild poliovirus importation into Israel showed the potential for silent circulation. Environmental surveillance may lead to early detection and facilitate preventive efforts. Countries using IPV only need to manage population immunity to transmission. Abstract: Poliovirus importations into polio-free countries represent a major concern during the final phases of global eradication of wild polioviruses (WPVs). We extend dynamic transmission models to demonstrate the dynamics of population immunity out through 2020 for three countries that only used inactivated poliovirus vaccine (IPV) for routine immunization: the US, Israel, and The Netherlands. For each country, we explore the vulnerability to re-established transmission following an importation for each poliovirus serotype, including the impact of immunization choices following the serotype 1 WPV importation that occurred in 2013 in Israel. As population immunity declines below the threshold required to prevent transmission, countries become at risk for re-established transmission. Although importations represent stochastic events that countries cannot fully control because people cross borders and polioviruses mainly cause asymptomatic infections, countries can ensure that any importations die out. Our results suggest that the general US population will remain above the threshold for transmission through 2020. In contrast, Israel became vulnerable to re-established transmission of importations of live polioviruses by the late 2000s. In Israel, the recent WPV importation and outbreak response use of bivalent oral poliovirus vaccine (bOPV) eliminated the vulnerability to an importation of poliovirus serotypes 1 and 3 for several years, but not serotype 2. The Netherlands experienced a serotype 1 WPV outbreak in 1992–1993 and became vulnerable to re-established transmission in religious communities with low vaccine acceptance around the year 2000, although the general population remains well-protected from widespread transmission. All countries should invest in active management of population immunity to avoid the potential circulation of imported live polioviruses. IPV-using countries may wish to consider prevention opportunities and/or ensure preparedness for response. Countries currently using a sequential IPV/OPV schedule should continue to use all licensed OPV serotypes until global OPV cessation to minimize vulnerability to circulation of imported polioviruses.