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. 2013 Oct 1;31(42):4911-6.
doi: 10.1016/j.vaccine.2013.06.106. Epub 2013 Jul 24.

Population immunity to polioviruses in the context of a large-scale wild poliovirus type 1 outbreak in Tajikistan, 2010

Nino Khetsuriani  1 , Mark A Pallansch, Shamsiddin Jabirov, Nargis Saparova, M Steven Oberste, Kathleen Wannemuehler, Pavel Ursu, Steve Wassilak, Rebecca Martin
Affiliations

Population immunity to polioviruses in the context of a large-scale wild poliovirus type 1 outbreak in Tajikistan, 2010

Nino Khetsuriani et al. Vaccine. .

Abstract

Background: A serosurvey to evaluate population immunity to polioviruses (PVs) in the context of the importation-related wild PV1 outbreak in Tajikistan in 2010 (461 confirmed cases among children and young adults) was conducted.

Methods: Serum specimens from a nationwide sample of 1-24 year-old persons selected through stratified cluster sampling (n=2447) were tested for neutralizing antibodies to all three PV types. Samples with titers<1:8 were considered seronegative. The serosurvey was conducted during the interval after mOPV1 supplementary immunization activities (SIAs) and before tOPV SIAs (targeting ages ≤ 15 years) implemented to control the outbreak. In the absence of pre-outbreak specimens, results for PV3 were used as a proxy for pre-outbreak PV1 immunity patterns.

Results: Overall, PV1 seroprevalence was 98.9%, PV2 seroprevalence was 98.8%, and PV3 seroprevalence was 86.9%. PV1 and PV2 seroprevalence exceeded 95% in all age groups and regions. PV3 seroprevalence was <90% in all age groups and regions, except 15-19 year-olds (91.7%) and Dushanbe (90.0%). PV3 seroprevalence was lowest among 1-4 (82.7%) and 5-9 (84.4%) year-olds, particularly among 1-4 year-olds in Kurgan-Tube (76.3%) and RRS (80.0%) regions. Birth cohorts immunized only through routine services (ages, 1-7 years) had lower PV3 seroprevalence than birth cohorts targeted by the SIAs during 1995-2002 (8-19 years): 82.5% versus 89.3%, p<0.001.

Conclusions: Suboptimal (<90%) PV3 seroprevalence across wide age range suggests the outbreak resulted from accumulation of susceptibles due to suboptimal coverage over a long time period, particularly in the birth cohorts immunized only through routine services and in areas where the outbreak began (Kurgan-Tube and RRS). High PV1 seroprevalence indicates that mOPV1 SIAs with expanded target age (≤ 15 years) succeeded in closing the immunity gap and ongoing WPV1 transmission is unlikely. To accelerate outbreak control in areas which have been polio-free for long time, expanding SIA target age should be considered.

Keywords: Antibodies against polioviruses; Poliomyelitis; Poliomyelitis outbreaks; Polioviruses; Population immunity; Seroprevalence; Tajikistan.

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Conflict of interest statement

Conflicts of interest

None declared by any co-author.

Figures

Fig. 1.
Fig. 1.
Reported WPV1 cases (per cent of all cases in the region) and proportion PV3-seronegative by region and age group, Tajikistan, 2010.
See this image and copyright information in PMC

References

    1. WHO. Certification of poliomyelitis eradication. Fifteenth meeting of the European Regional Certification Commission. WHO; 2005. Available at: http://www.euro.who.int/data/assets/pdf_file/0003/79374/E88105.pdf [accessed 05.03.13].
    1. CDC. Outbreaks following wild poliovirus importations – Europe, Africa, and Asia, January–September 2009. MMWR Weekly: 2010;59:1393–9. - PubMed
    1. WHO. Operation MECACAR: eradicating polio. Final report, 1995–2000. WHO; 2001. Available at: http://pdf.usaid.gov/pdfdocs/PNACP804.pdf [accessed 05.03.13].
    1. State Committee on Statistics of the Republic of Tajikistan. Tajikistan Multiple Indicator Cluster Survey 2005. Final Report. Dushanbe; 2007. Available at: http://www.stat.tj/en/img/e1aef37486b7a4528ba06bfcb918347f_1280833057.pdf [accessed 05.03.13].
    1. UNICEF and State Committee on Statistics of the Republic of Tajikistan. Tajikistan Living Standards Measurement Survey (LSMS) 2007. Dushanbe; 2007. Available at: http://www.tojikinfo.tj/en/download/files/UNICEF%20TLSS%20Report%20Eng.pdf [accessed 05.03.13].

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