Assessing Change in Avian Influenza A(H7N9) Virus Infections During the Fourth Epidemic — China, September 2015–August 2016

Xiang, Nijuan; Li, Xiyan; Ren, Ruiqi; Wang, Dayan; Zhou, Suizan; Greene, Carolyn M.; Song, Ying; Zhou, Lei; Yang, Lei; Davis, Christal; Zhang, Ye; Wang, Yali; Zhao, Jian; Li, Xiaodan; Iuliano, A. Danielle; Havers, Fiona; Olsen, Sonja J.; Uyeki, Timothy M.; Azziz‐Baumgartner, Eduardo; Trock, Susan C.; Liu, Bo; Sui, Haitian; Huang, Xu; Zhang, Yanping; Ni, Daxin; Feng, Zijian; Shu, Yuelong; Li, Qun

doi:10.15585/mmwr.mm6549a2

Cited by 49 publications

(53 citation statements)

References 9 publications

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“…Studies have shown that the demographic, epidemiologic and virologic characteristics of H7N9 cases from these epidemics remained unchanged, while the epidemic curve illustrated a decline in the magnitude of outbreaks over time, particularly in the third and fourth seasons in 2015 and 2016. ( 2 , 3 ) However, since September 2016, not only has the fifth outbreak started earlier than usual, but a steep increase in the number of humans infected with H7N9 virus has also been observed, causing domestic and international concern. On 9 January 2017, China notified the World Health Organization through the International Health Regulations mechanism of 106 cases.…”

Section: Introductionmentioning

confidence: 99%

Sudden increase in human infection with avian influenza A(H7N9) virus in China, September–December 2016

Zhou

Ren

Yang

et al. 2017

WPSAR

Self Cite

102

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Since the first outbreak of avian influenza A(H7N9) virus in humans was identified in 2013, there have been five seasonal epidemics observed in China. An earlier start and a steep increase in the number of humans infected with H7N9 virus was observed between September and December 2016, raising great public concern in domestic and international societies. The epidemiological characteristics of the recently reported confirmed H7N9 cases were analysed. The results suggested that although more cases were reported recently, most cases in the fifth epidemic were still highly sporadically distributed without any epidemiology links; the main characteristics remained unchanged and the genetic characteristics of virus strains that were isolated in this epidemic remained similar to earlier epidemics. Interventions included live poultry market closures in several cities that reported more H7N9 cases recently.

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Section: Introductionmentioning

confidence: 99%

Sudden increase in human infection with avian influenza A(H7N9) virus in China, September–December 2016

Zhou

Ren

Yang

et al. 2017

WPSAR

Self Cite

102

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“…The novel avian-origin influenza A strain (H7N9), initially identified in 2013, is now circulating with almost annual frequency and accounted for one-third of all cases n the 2016/2017 influenza season. Most worringly, the case-fatality rate for this virus exceeds 40% (1)(2)(3). In addition, H7N9 influenza viruses have recently been assessed as having the highest potential pandemic risk of any novel influenza A viruses; this assessment is based on recent studies which indicate that H7N9 viruses have increased genetic diversity, geographical distribution, and in recent outbreaks a significantly higher proportion of H7N9-infected patients have needed care in an ICU (1)(2)(3).…”

Section: Introductionmentioning

confidence: 99%

“…Most worringly, the case-fatality rate for this virus exceeds 40% (1)(2)(3). In addition, H7N9 influenza viruses have recently been assessed as having the highest potential pandemic risk of any novel influenza A viruses; this assessment is based on recent studies which indicate that H7N9 viruses have increased genetic diversity, geographical distribution, and in recent outbreaks a significantly higher proportion of H7N9-infected patients have needed care in an ICU (1)(2)(3). For the past 70 years vaccination has been the mainstay healthcare strategy against influenza infection (4)(5)(6).…”

Section: Introductionmentioning

confidence: 99%

Novel Bivalent Viral-Vectored Vaccines Induce Potent Humoral and Cellular Immune Responses Conferring Protection against Stringent Influenza A Virus Challenge

Chinnakannan

Mullarkey

Ulaszewska

et al. 2017

The Journal of Immunology

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Abstract:Seasonal influenza viruses (IAV) are a common cause of acute respiratory illness worldwide and generate a significant socio-economic burden. IAV rapidly mutate, necessitating annual vaccine reformulation as traditional vaccines do not typically induce broad-spectrum immunity. In addition to seasonal infections, emerging pandemic influenza viruses present a continued threat to global public health. Pandemic influenza viruses have consistently higher attack rates and are typically associated with greater mortality as compared to seasonal strains. Ongoing strategies to improve vaccine efficacy typically focus on providing broad-spectrum immunity, and while both B and T cells can mediate heterosubtypic responses, typical vaccine development will augment either humoral or cellular immunity. However, multipronged approaches, targeting several antigens, may limit the generation of viral escape mutants. There are few vaccine platforms that can deliver multiple antigens and generate robust cellular and humoral immunity. In this work, we describe a novel vaccination strategy, tested pre-clinically in mice, for the delivery of novel bivalent viral-vectored vaccines. Here, we show this strategy elicits potent T cell responses toward highly conserved internal antigens, whilst simultaneously inducing high levels of antibodies towards hemagglutinin (HA). Importantly, these humoral responses generate longlived plasma cells and generate antibodies capable of neutralising variant HA-expressing pseudotyped lentiviruses. Significantly, these novel viral-vectored vaccines induce strong immune responses capable of conferring protection in a stringent influenza A virus challenge.Thus, this vaccination regimen induces lasting efficacy toward influenza. Importantly, the simultaneous delivery of dual antigens may alleviate the selective pressure thought to potentiate antigenic diversity in avian influenza viruses.

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“…Epidemiological data suggested that avian influenza A(H7N9) infections were associated with exposure to live poultry markets (LPMs) 2, 3, 4, 5, 6. To control its impact, temporary or permanent closure of live poultry markets has been implemented by many local governments, leading to a declining trend of laboratory‐confirmed cases in the first four waves 7, 8, 9, 10, 11. However, an unprecedented outbreak of human infection with avian influenza A(H7N9) virus, identified as the fifth wave, occurred in China from September 2016, and a number of cases reported in the fifth wave exceeded those reported in the previous waves in China 8, 9, 10, 12…”

Section: Introductionmentioning

confidence: 99%

Comparison of the three waves of avian influenza A(H7N9) virus circulation since live poultry markets were permanently closed in the main urban areas in Zhejiang Province, July 2014‐June 2017

Cheng

Wang

Shen

et al. 2018

Influenza Resp Viruses

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BackgroundThe sudden increase in the number of human cases infected with avian influenza A(H7N9) virus after September 2016 raised global concern.ObjectivesTo assess the changes in epidemiological characteristics of H7N9 cases since the massive closure of live poultry markets (LPMs) in the main urban areas in Zhejiang province.MethodsWe used descriptive statistics to compare epidemiological characteristics of the three distinct waves of H7N9 cases in Zhejiang province. The rural or urban cases were defined according to the location where the patients had exposure within 2 weeks before illness onset.ResultsBetween July 2014 and June 2017, 166 H7N9 cases were reported in Zhejiang province, with 45, 34, and 87 cases reported in the third, fourth, and fifth wave, respectively. Across the three waves, most reported cases were from rural areas. A similar percentage of cases in all three waves reported exposure to LPMs, raising poultry at home or around the house, as well as occupational exposure. Compared to the third (80.00%) and fourth wave (70.59%), a significantly larger proportion of cases from the non‐LPMs closure areas were observed in the fifth wave (89.66%) (P = .034).ConclusionEpidemiological characteristics of human cases infected with avian influenza A(H7N9) virus had generally remained unchanged since the massive closure of LPMs in the main urban area of Zhejiang province. The sudden increase in the number of H7N9 cases in the fifth wave was mainly attributed to the excessive cases reported from areas where LPMs were not permanently closed.

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Assessing Change in Avian Influenza A(H7N9) Virus Infections During the Fourth Epidemic — China, September 2015–August 2016

Cited by 49 publications

References 9 publications

Sudden increase in human infection with avian influenza A(H7N9) virus in China, September–December 2016

Sudden increase in human infection with avian influenza A(H7N9) virus in China, September–December 2016

Novel Bivalent Viral-Vectored Vaccines Induce Potent Humoral and Cellular Immune Responses Conferring Protection against Stringent Influenza A Virus Challenge

Comparison of the three waves of avian influenza A(H7N9) virus circulation since live poultry markets were permanently closed in the main urban areas in Zhejiang Province, July 2014‐June 2017

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