Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014

Nijuan Xiang; Tian Bai; Kai Kang; Hui Yuan; Suizan Zhou; Ruiqi Ren; Xiuying Li; Jiabing Wu; Liquan Deng; Ge Zeng; Xianjun Wang; Shenghua Mao; Jian Shi; Rongbao Gao; Tao Chen; Sumei Zou; Dan Li; Fiona Havers; Marc-Alain Widdowson; Carolyn M Greene; Yanping Zhang; Daxin Ni; Xiaoqing Liu; Qun Li; Yuelong Shu

doi:10.1111/irv.12435

Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014

Nijuan Xiang, Tian Bai, Kai Kang, Hui Yuan, Suizan Zhou, Ruiqi Ren, Xiuying Li, Jiabing Wu, Liquan Deng, Ge Zeng, Xianjun Wang, Shenghua Mao, Jian Shi, Rongbao Gao, Tao Chen, Sumei Zou, Dan Li, Fiona Havers, Marc-Alain Widdowson, Carolyn M GreeneYanping Zhang, Daxin Ni, Xiaoqing Liu, Qun Li, Yuelong Shu

Institute of Tropical Medicine

Research output: Contribution to journal › A1: Web of Science-article › peer-review

Abstract

BACKGROUND: The first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.

OBJECTIVES: We assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.

PATIENTS/METHODS: From March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2-3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.

RESULTS: Among general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02-0.44) were positive by MN. Among 61 healthcare and 117 non-healthcare contacts' sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.

CONCLUSIONS: There was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.

Original language	English
Journal	Influenza and Other Respiratory Viruses
Volume	11
Issue number	2
Pages (from-to)	170-176
Number of pages	7
ISSN	1750-2640
DOIs	https://doi.org/10.1111/irv.12435
Publication status	Published - 2017

Keywords

Adult
Animals
Antibodies, Viral/blood
China/epidemiology
Female
Humans
Influenza A Virus, H7N9 Subtype/immunology
Influenza in Birds/epidemiology
Influenza, Human/epidemiology
Male
Orthomyxoviridae Infections/epidemiology
Poultry/virology
Seroepidemiologic Studies
Young Adult

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10.1111/irv.12435

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Xiang, N., Bai, T., Kang, K., Yuan, H., Zhou, S., Ren, R., Li, X., Wu, J., Deng, L., Zeng, G., Wang, X., Mao, S., Shi, J., Gao, R., Chen, T., Zou, S., Li, D., Havers, F., Widdowson, M.-A., ... Shu, Y. (2017). Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014. Influenza and Other Respiratory Viruses, 11(2), 170-176. https://doi.org/10.1111/irv.12435

@article{a6a264d49fef482483d51d36c33499d3,

title = "Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014",

abstract = "BACKGROUND: The first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.OBJECTIVES: We assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.PATIENTS/METHODS: From March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2-3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.RESULTS: Among general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02-0.44) were positive by MN. Among 61 healthcare and 117 non-healthcare contacts' sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.CONCLUSIONS: There was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.",

keywords = "Adult, Animals, Antibodies, Viral/blood, China/epidemiology, Female, Humans, Influenza A Virus, H7N9 Subtype/immunology, Influenza in Birds/epidemiology, Influenza, Human/epidemiology, Male, Orthomyxoviridae Infections/epidemiology, Poultry/virology, Seroepidemiologic Studies, Young Adult",

author = "Nijuan Xiang and Tian Bai and Kai Kang and Hui Yuan and Suizan Zhou and Ruiqi Ren and Xiuying Li and Jiabing Wu and Liquan Deng and Ge Zeng and Xianjun Wang and Shenghua Mao and Jian Shi and Rongbao Gao and Tao Chen and Sumei Zou and Dan Li and Fiona Havers and Marc-Alain Widdowson and Greene, {Carolyn M} and Yanping Zhang and Daxin Ni and Xiaoqing Liu and Qun Li and Yuelong Shu",

note = "{\textcopyright} 2016 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.",

year = "2017",

doi = "10.1111/irv.12435",

language = "English",

volume = "11",

pages = "170--176",

journal = "Influenza and Other Respiratory Viruses",

issn = "1750-2640",

publisher = "John Wiley & Sons",

number = "2",

}

Xiang, N, Bai, T, Kang, K, Yuan, H, Zhou, S, Ren, R, Li, X, Wu, J, Deng, L, Zeng, G, Wang, X, Mao, S, Shi, J, Gao, R, Chen, T, Zou, S, Li, D, Havers, F, Widdowson, M-A, Greene, CM, Zhang, Y, Ni, D, Liu, X, Li, Q & Shu, Y 2017, 'Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014', Influenza and Other Respiratory Viruses, vol. 11, no. 2, pp. 170-176. https://doi.org/10.1111/irv.12435

TY - JOUR

T1 - Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014

AU - Xiang, Nijuan

AU - Bai, Tian

AU - Kang, Kai

AU - Yuan, Hui

AU - Zhou, Suizan

AU - Ren, Ruiqi

AU - Li, Xiuying

AU - Wu, Jiabing

AU - Deng, Liquan

AU - Zeng, Ge

AU - Wang, Xianjun

AU - Mao, Shenghua

AU - Shi, Jian

AU - Gao, Rongbao

AU - Chen, Tao

AU - Zou, Sumei

AU - Li, Dan

AU - Havers, Fiona

AU - Widdowson, Marc-Alain

AU - Greene, Carolyn M

AU - Zhang, Yanping

AU - Ni, Daxin

AU - Liu, Xiaoqing

AU - Li, Qun

AU - Shu, Yuelong

PY - 2017

Y1 - 2017

N2 - BACKGROUND: The first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.OBJECTIVES: We assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.PATIENTS/METHODS: From March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2-3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.RESULTS: Among general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02-0.44) were positive by MN. Among 61 healthcare and 117 non-healthcare contacts' sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.CONCLUSIONS: There was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.

AB - BACKGROUND: The first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.OBJECTIVES: We assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.PATIENTS/METHODS: From March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2-3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.RESULTS: Among general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02-0.44) were positive by MN. Among 61 healthcare and 117 non-healthcare contacts' sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.CONCLUSIONS: There was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.

KW - Adult

KW - Animals

KW - Antibodies, Viral/blood

KW - China/epidemiology

KW - Female

KW - Humans

KW - Influenza A Virus, H7N9 Subtype/immunology

KW - Influenza in Birds/epidemiology

KW - Influenza, Human/epidemiology

KW - Male

KW - Orthomyxoviridae Infections/epidemiology

KW - Poultry/virology

KW - Seroepidemiologic Studies

KW - Young Adult

U2 - 10.1111/irv.12435

DO - 10.1111/irv.12435

M3 - A1: Web of Science-article

C2 - 27762061

SN - 1750-2640

VL - 11

SP - 170

EP - 176

JO - Influenza and Other Respiratory Viruses

JF - Influenza and Other Respiratory Viruses

IS - 2

ER -

Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014

Abstract

Keywords

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