Early Pandemic Influenza (2009 H1N1) in Ho Chi Minh City, Vietnam: A Clinical Virological and Epidemiological Analysis

English version České info

Background:
To date, little is known about the initial spread and response to the 2009 pandemic of novel influenza A (“2009 H1N1”) in tropical countries. Here, we analyse the early progression of the epidemic from 26 May 2009 until the establishment of community transmission in the second half of July 2009 in Ho Chi Minh City (HCMC), Vietnam. In addition, we present detailed systematic viral clearance data on 292 isolated and treated patients and the first three cases of selection of resistant virus during treatment in Vietnam.

Methods and Findings:
Data sources included all available health reports from the Ministry of Health and relevant health authorities as well as clinical and laboratory data from the first confirmed cases isolated at the Hospital for Tropical Diseases in HCMC. Extensive reverse transcription (RT)-PCR diagnostics on serial samples, viral culture, neuraminidase-inhibition testing, and sequencing were performed on a subset of 2009 H1N1 confirmed cases. Virological (PCR status, shedding) and epidemiological (incidence, isolation, discharge) data were combined to reconstruct the initial outbreak and the establishment of community transmission. From 27 April to 24 July 2009, approximately 760,000 passengers who entered HCMC on international flights were screened at the airport by a body temperature scan and symptom questionnaire. Approximately 0.15% of incoming passengers were intercepted, 200 of whom tested positive for 2009 H1N1 by RT-PCR. An additional 121 out of 169 nontravelers tested positive after self-reporting or contact tracing. These 321 patients spent 79% of their PCR-positive days in isolation; 60% of PCR-positive days were spent treated and in isolation. Influenza-like illness was noted in 61% of patients and no patients experienced pneumonia or severe outcomes. Viral clearance times were similar among patient groups with differing time intervals from illness onset to treatment, with estimated median clearance times between 2.6 and 2.8 d post-treatment for illness-to-treatment intervals of 1–4 d, and 2.0 d (95% confidence interval 1.5–2.5) when treatment was started on the first day of illness.

Conclusions:
The patients described here represent a cross-section of infected individuals that were identified by temperature screening and symptom questionnaires at the airport, as well as mildly symptomatic to moderately ill patients who self-reported to hospitals. Data are observational and, although they are suggestive, it is not possible to be certain whether the containment efforts delayed community transmission in Vietnam. Viral clearance data assessed by RT-PCR showed a rapid therapeutic response to oseltamivir.

: Please see later in the article for the Editors' Summary

Vyšlo v časopise: Early Pandemic Influenza (2009 H1N1) in Ho Chi Minh City, Vietnam: A Clinical Virological and Epidemiological Analysis. PLoS Med 7(5): e32767. doi:10.1371/journal.pmed.1000277
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pmed.1000277

Souhrn

Zdroje

1. 2009 Influenza pandemic (H1N1) 2009: Viet Nam, patient data - 20090708.2450. ProMED-mail

2. 2009 Influenza pandemic (H1N1) 2009: Viet Nam, patient data update - 20090809.2819. ProMED-mail

3. 2009 Influenza pandemic (H1N1) 2009: Viet Nam, virus clearance - 20091011.3519. ProMED-mail

4. 2009 Daily health reports. Ho Chi Minh City Health Services

5. WHO/USCDC 2009 CDC Protocol for realtime RTPCR for influenza A(H1N1) - revision 1 30 April 2009

6. GuanY

PeirisJS

LipatovAS

EllisTM

DyrtingKC

2002 Emergence of multiple genotypes of H5N1 avian influenza viruses in Hong Kong SAR. Proc Natl Acad Sci U S A 99 8950 8955

7. PotierM

MameliL

BelisleM

DallaireL

MelanconSB

1979 Fluorometric assay of neuraminidase with a sodium (4-methylumbelliferyl-alpha-D-N-acetylneuraminate) substrate. Anal Biochem 94 287 296

8. WetherallNT

TrivediT

ZellerJ

Hodges-SavolaC

McKimm-BreschkinJL

2003 Evaluation of neuraminidase enzyme assays using different substrates to measure susceptibility of influenza virus clinical isolates to neuraminidase inhibitors: report of the neuraminidase inhibitor susceptibility network. J Clin Microbiol 41 742 750

9. MatrosovichM

MatrosovichT

CarrJ

RobertsNA

KlenkHD

2003 Overexpression of the alpha-2,6-sialyltransferase in MDCK cells increases influenza virus sensitivity to neuraminidase inhibitors. J Virol 77 8418 8425

10. ReichNG

LesslerJ

CummingsDA

BrookmeyerR

2009 Estimating incubation period distributions with coarse data. Stat Med 28 2769 2784

11. FraserC

DonnellyCA

CauchemezS

HanageWP

Van KerkhoveMD

2009 Pandemic potential of a strain of influenza A (H1N1): early findings. Science 324 1557 1561

12. FergusonNM

CummingsDA

CauchemezS

FraserC

RileyS

2005 Strategies for containing an emerging influenza pandemic in Southeast Asia. Nature 437 209 214

13. CowlingBJ

FangVJ

RileyS

Malik PeirisJS

LeungGM

2009 Estimation of the serial interval of influenza. Epidemiology 20 344 347

14. WallingaJ

LipsitchM

2007 How generation intervals shape the relationship between growth rates and reproductive numbers. Proc Biol Sci 274 599 604

15. de SilvaUC

WarachitJ

WaicharoenS

ChittaganpitchM

2009 A preliminary analysis of the epidemiology of influenza A(H1N1)v virus infection in Thailand from early outbreak data, June-July 2009. Euro Surveill 14 19292

16. NguyenHT

DharanNJ

LeMT

NguyenNB

NguyenCT

2009 National influenza surveillance in Vietnam, 2006-2007. Vaccine 28 398 402

17. SimmermanJM

UyekiTM

2008 The burden of influenza in East and South-East Asia: a review of the English language literature. Influenza Other Respi Viruses 2 81 92

18. MillsCE

RobinsJM

BergstromCT

LipsitchM

2006 Pandemic influenza: risk of multiple introductions and the need to prepare for them. PLoS Med 3 e135 doi:10.1371/journal.pmed.0030135

19. CooperBS

PitmanRJ

EdmundsWJ

GayNJ

2006 Delaying the international spread of pandemic influenza. PLoS Med 3 e212 doi:10.1371/journal.pmed.0030212

20. Scalia TombaG

WallingaJ

2008 A simple explanation for the low impact of border control as a countermeasure to the spread of an infectious disease. Math Biosci 214 70 72

21. ReedC

AnguloFJ

SwerdlowDL

LipsitchM

MeltzerMI

2009 Estimates of the prevalence of pandemic (H1N1) 2009, United States, April-July 2009. Emerg Infect Dis 15 2004 2007

22. Novel influenza A(H1N1) investigation team 2009 Description of the early stage of pandemic (H1N1) 2009 in Germany, 27 April-16 June 2009. Euro Surveill 14 19295

23. HahneS

DonkerT

MeijerA

TimenA

van SteenbergenJ

2009 Epidemiology and control of influenza A(H1N1)v in the Netherlands: the first 115 cases. Euro Surveill 14 19267

24. HaydenFG

TreanorJJ

FritzRS

LoboM

BettsRF

1999 Use of the oral neuraminidase inhibitor oseltamivir in experimental human influenza: randomized controlled trials for prevention and treatment. JAMA 282 1240 1246

25. CunhaBA

PherezFM

SchochP

2009 Diagnostic importance of relative lymphopenia as a marker of swine influenza (H1N1) in adults. Clin Infect Dis 49 1454 1456

26. CaoB

LiXW

MaoY

WangJ

LuHZ

2009 Clinical features of the initial cases of 2009 pandemic influenza A (H1N1) virus infection in China. N Engl J Med 361 2507 2517

27. WhitleyRJ

HaydenFG

ReisingerKS

YoungN

DutkowskiR

2001 Oral oseltamivir treatment of influenza in children. Pediatr Infect Dis J 20 127 133

28. De SerresF

RouleauI

HamelinM

QuachC

BoulianneN

2009 Shedding of novel 2009 pandemic H1N1 (nH1N1) virus at one week post illness onset [Abstract K-1918a]. In: Proceedings of ICAAC; 12–15 September 2009; San Francisco, United States

29. EggertsonL

2009 Pandemic (H1N1) 2009 lives in some people for at least eight days after symptoms develop. Can Med Assoc J 181 E203

30. LyeD

ChowA

TanA

WinN

WinM

2009 Oseltamivir therapy and viral shedding in pandemic (H1N1) 2009. In: Proceedings of ICAAC; 12–15 September 2009; San Francisco, United States

31. BhattaraiA

SessionsW

PalekarR

BermanL

WinterJ

2009 Viral shedding patterns of the pandemic influenza A H1N1 virus during an outbreak associated with an elementary school in Pennsylvania, May-June 2009. In: Proceedings of Annual Meeting of the Infectious Diseases Society of America. 29 October–1 November 2009; Philadelphia, Pennsylvania, United States

32. WitkopCT

DuffyMR

MaciasEA

GibbonsTF

EscobarJD

2009 Novel influenza A (H1N1) outbreak at the U.S. Air Force Academy: epidemiology and viral shedding duration. Am J Prev Med 38 121 126

33. PanningM

EickmannM

LandtO

MonazahianM

OlschlagerS

2009 Detection of influenza A(H1N1)v virus by real-time RT-PCR. Euro Surveill 14 19329

34. KisoM

MitamuraK

Sakai-TagawaY

ShiraishiK

KawakamiC

2004 Resistant influenza A viruses in children treated with oseltamivir: descriptive study. Lancet 364 759 765

35. WhitleyRJ

HaydenFG

ReisingerKS

YoungN

DutkowskiR

2001 Oral oseltamivir treatment of influenza in children. Pediatr Infect Dis J 20 127

36. GubarevaLV

KaiserL

MatrosovichMN

Soo-HooY

HaydenFG

2001 Selection of influenza virus mutants in experimentally infected volunteers treated with oseltamivir. J Infect Dis 183 523 531

37. StephensonI

DemocratisJ

LackenbyA

McNallyT

SmithJ

2009 Neuraminidase inhibitor resistance after oseltamivir treatment of acute influenza A and B in children. Clin Infect Dis 48 389 396

38. BansalS

PourbohloulB

HupertN

GrenfellB

MyersLA

2009 The shifting demographic landscape of influenza, version 2. PLoS Currents Influenza. Available: http://knol.google.com/k/the-shifting-demographic-landscape-of-influenza

39. BoniMF

GogJR

AndreasenV

FeldmanMW

2006 Epidemic dynamics and antigenic evolution in a single season of influenza A. Proc Biol Sci 273 1307 1316

40. BoniMF

ManhBH

ThaiPQ

FarrarJ

HienTT

2009 Modelling the progression of pandemic influenza A (H1N1) in Vietnam and the opportunities for reassortment with other influenza viruses. BMC Medicine 7 43