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An outbreak of type π vaccine-derived poliovirus in Sichuan province, China: emergence and circulation in an under-immunized population.

Wang HB, Fang G, Yu WZ, Du F, Fan CX, Liu QL, Hao LX, Liu Y, Zheng JS, Qin ZY, Xia W, Zhang SY, Yin ZD, Jing Q, Zhang YX, Huang RN, Yang RP, Tong WB, Qi Q, Guan XJ, Jing YL, Ma QL, Wang J, Ma XZ, Chen N, Zheng HR, Li YQ, Ma C, Su QR, Reilly KH, Luo HM, Wu XP, Wen N, Yang WZ - PLoS ONE (2014)

Bottom Line: Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine.High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated.Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.

View Article: PubMed Central - PubMed

Affiliation: Chinese Center for Disease Control and Prevention, Nanwei Rd 27#, Xicheng District, Beijing 100050, PR China; Peking University Clinical Research Institute, Xueyuan Rd 38#, Haidian District, Beijing 100191, PR China.

ABSTRACT

Background: During August 2011-February 2012, an outbreak of type Π circulating vaccine-derived poliovirus (cVDPVs) occurred in Sichuan Province, China.

Methods: A field investigation of the outbreak was conducted to characterize outbreak isolates and to guide emergency response. Sequence analysis of poliovirus capsid protein VP1 was performed to determine the viral propagation, and a coverage survey was carried out for risk assessment.

Results: One clinical compatible polio case and three VDPV cases were determined in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province. Case patients were unimmunized children, 0.8-1 years old. Genetic sequencing showed that the isolates diverged from the VP1 region of the type Π Sabin strain by 5-12 nucleotides (nt) and shared the same 5 nt VP1 substitutions, which indicate single lineage of cVDPVs. Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine. Supplementary immunization activities (SIAs) were conducted in February-May, 2012, and the strain has not been isolated since.

Conclusion: High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated. Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.

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Related in: MedlinePlus

Distribution of prefectures where SIAs were conducted in Sichuan, Qinghai and Gansu provinces.Note: SIAs, supplementary immunization activities.
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pone-0113880-g002: Distribution of prefectures where SIAs were conducted in Sichuan, Qinghai and Gansu provinces.Note: SIAs, supplementary immunization activities.

Mentions: SIAs were conducted in Ngawa Tibetan and Qiang Autonomous Prefecture and neighboring prefectures, including Ganzi and Liangshan prefectures in Sichuan Province, Guoluo and Yushu prefectures in Qinghai Province, as well as Linxia, Gannan and Longnan prefectures in Gansu Province (Table 2 and Fig. 2).


An outbreak of type π vaccine-derived poliovirus in Sichuan province, China: emergence and circulation in an under-immunized population.

Wang HB, Fang G, Yu WZ, Du F, Fan CX, Liu QL, Hao LX, Liu Y, Zheng JS, Qin ZY, Xia W, Zhang SY, Yin ZD, Jing Q, Zhang YX, Huang RN, Yang RP, Tong WB, Qi Q, Guan XJ, Jing YL, Ma QL, Wang J, Ma XZ, Chen N, Zheng HR, Li YQ, Ma C, Su QR, Reilly KH, Luo HM, Wu XP, Wen N, Yang WZ - PLoS ONE (2014)

Distribution of prefectures where SIAs were conducted in Sichuan, Qinghai and Gansu provinces.Note: SIAs, supplementary immunization activities.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263476&req=5

pone-0113880-g002: Distribution of prefectures where SIAs were conducted in Sichuan, Qinghai and Gansu provinces.Note: SIAs, supplementary immunization activities.
Mentions: SIAs were conducted in Ngawa Tibetan and Qiang Autonomous Prefecture and neighboring prefectures, including Ganzi and Liangshan prefectures in Sichuan Province, Guoluo and Yushu prefectures in Qinghai Province, as well as Linxia, Gannan and Longnan prefectures in Gansu Province (Table 2 and Fig. 2).

Bottom Line: Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine.High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated.Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.

View Article: PubMed Central - PubMed

Affiliation: Chinese Center for Disease Control and Prevention, Nanwei Rd 27#, Xicheng District, Beijing 100050, PR China; Peking University Clinical Research Institute, Xueyuan Rd 38#, Haidian District, Beijing 100191, PR China.

ABSTRACT

Background: During August 2011-February 2012, an outbreak of type Π circulating vaccine-derived poliovirus (cVDPVs) occurred in Sichuan Province, China.

Methods: A field investigation of the outbreak was conducted to characterize outbreak isolates and to guide emergency response. Sequence analysis of poliovirus capsid protein VP1 was performed to determine the viral propagation, and a coverage survey was carried out for risk assessment.

Results: One clinical compatible polio case and three VDPV cases were determined in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province. Case patients were unimmunized children, 0.8-1 years old. Genetic sequencing showed that the isolates diverged from the VP1 region of the type Π Sabin strain by 5-12 nucleotides (nt) and shared the same 5 nt VP1 substitutions, which indicate single lineage of cVDPVs. Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine. Supplementary immunization activities (SIAs) were conducted in February-May, 2012, and the strain has not been isolated since.

Conclusion: High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated. Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.

Show MeSH
Related in: MedlinePlus