Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Jul;9(4):216-24.
doi: 10.1111/irv.12323.

Virological characterization of influenza H1N1pdm09 in Vietnam, 2010-2013

Hang K L Nguyen  1 , Phuong T K Nguyen  2 , Thach C Nguyen  1 , Phuong V M Hoang  1 , Thanh T Le  1 , Cuong D Vuong  1 , Anh P Nguyen  1 , Loan T T Tran  3 , Binh G Nguyen  4 , Mai Q Lê  1
Affiliations

Virological characterization of influenza H1N1pdm09 in Vietnam, 2010-2013

Hang K L Nguyen et al. Influenza Other Respir Viruses. 2015 Jul.

Abstract

Objectives: Influenza A/H1N1pdm09 virus was first detected in Vietnam on May 31, 2009, and continues to circulate in Vietnam as a seasonal influenza virus. This study has monitored genotypic and phenotypic changes in this group of viruses during 2010-2013 period.

Design and setting: We sequenced hemagglutinin (HA) and neuraminidase (NA) genes from representative influenza A/H1N1pdm09 and compared with vaccine strain A/California/07/09 and other contemporary isolates from neighboring countries. Hemagglutination inhibition (HI) and neuraminidase inhibition (NAI) assays also were performed on these isolates.

Sample: Representative influenza A/H1N1pdm09 isolates (n = 61) from ILI and SARI surveillances in northern Vietnam between 2010 and 2013.

Main outcome measures and results: The HA and NA phylogenies revealed six and seven groups, respectively. Five isolates (8·2%) had substitutions G155E and N156K in the HA, which were associated with reduced HI titers by antiserum raised against the vaccine virus A/California/07/2009. One isolate from 2011 and one isolate from 2013 had a predicted H275Y substitution in the neuraminidase molecule, which was associated with reduced susceptibility to oseltamivir in a NAI assay. We also identified a D222N change in the HA of a virus isolated from a fatal case in 2013.

Conclusions: Significant genotypic and phenotypic changes in A/ H1N1pdm09 influenza viruses were detected by the National Influenza Surveillance System (NISS) in Vietnam between 2010 and 2013 highlighting the value of this system to Vietnam and to the region. Sustained NISS and continued virological monitoring of seasonal influenza viruses are required for vaccine policy development in Vietnam. 3.

Keywords: Influenza A/H1N1pdm09; Vietnam; the vaccine virus A/California/07/2009; virological characterization.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Proportion of ILI patients in Vietnam infected with (RT-PCR reactive) the influenza virus genotypes shown between 2009 and 2013.
Figure 2
Figure 2
Number of A/H1N1pdm09 infections detected by RT-PCR during ILI and SVP surveillance, in Vietnam, 2010–2013.
Figure 3
Figure 3
Maximum likelihood phylogeny of the HA genes of A/H1N1pdm09 viruses circulating in Vietnam, 2009–2013.
Figure 4
Figure 4
Maximum Likelihood phylogeny of NA genes of A/H1N1pdm09 viruses circulating in Vietnam, 2009–2013.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. WHO. Evolution of a Pandemic A(H1N1) 2009, April 2009–August 2010. 2nd edn. Switzerland: WHO; 2010. . Available at http://apps.who.int/iris/bitstream/10665/78414/1/9789241503051_eng.pdf (Accessed 28 May 2014)
    1. An LV, Bao Chi LT, Bach NH, et al. Molecular characterization of influenza A(H1N1)pdm09 virus circulating during the 2009 outbreak in Thua Thien Hue, Vietnam. J Infect Dev Ctries. 2013;7:235–242. - PubMed
    1. Dawood FS, Iuliano AD, Reed C, et al. Estimated global mortality associated with the first 12 months of 2009 pandemic influenza A H1N1 virus circulation: a modelling study. Lancet Infect Dis. 2012;12:687–695. - PubMed
    1. Weekly NISS Report-29 Nov 2013-#47.
    1. El Moussi A, Ben Hadj Kacem MA, Pozo F, et al. Genetic diversity of HA1 domain of heammaglutinin gene of influenza A(H1N1)pdm09 in Tunisia. Virol J. 2013;10:150. - PMC - PubMed

Publication types

MeSH terms