Transmission Characteristics of the 2009 H1N1 Influenza Pandemic: Comparison of 8 Southern Hemisphere Countries

English version České info

While in Northern hemisphere countries, the pandemic H1N1 virus (H1N1pdm) was introduced outside of the typical influenza season, Southern hemisphere countries experienced a single wave of transmission during their 2009 winter season. This provides a unique opportunity to compare the spread of a single virus in different countries and study the factors influencing its transmission. Here, we estimate and compare transmission characteristics of H1N1pdm for eight Southern hemisphere countries/states: Argentina, Australia, Bolivia, Brazil, Chile, New Zealand, South Africa and Victoria (Australia). Weekly incidence of cases and age-distribution of cumulative cases were extracted from public reports of countries' surveillance systems. Estimates of the reproduction numbers, R₀, empirically derived from the country-epidemics' early exponential phase, were positively associated with the proportion of children in the populations (p = 0.004). To explore the role of demography in explaining differences in transmission intensity, we then fitted a dynamic age-structured model of influenza transmission to available incidence data for each country independently, and for all the countries simultaneously. Posterior median estimates of R₀ ranged 1.2–1.8 for the country-specific fits, and 1.29–1.47 for the global fits. Corresponding estimates for overall attack-rate were in the range 20–50%. All model fits indicated a significant decrease in susceptibility to infection with age. These results confirm the transmissibility of the 2009 H1N1 pandemic virus was relatively low compared with past pandemics. The pattern of age-dependent susceptibility found confirms that older populations had substantial –⁠ though partial -⁠ pre-existing immunity, presumably due to exposure to heterologous influenza strains. Our analysis indicates that between-country-differences in transmission were at least partly due to differences in population demography.

Vyšlo v časopise: Transmission Characteristics of the 2009 H1N1 Influenza Pandemic: Comparison of 8 Southern Hemisphere Countries. PLoS Pathog 7(9): e32767. doi:10.1371/journal.ppat.1002225
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.ppat.1002225

Souhrn

Zdroje

1. World Health Organization 2009 Statement by WHO Director-General, Dr Margaret Chan. Available: http://www.who.int/mediacentre/news/statements/2009/h1n1_20090429/en/index.html

2. World Health Organization 2009 Pandemic (H1N1) 2009 -⁠ weekly update 81. Available: http://www.who.int/csr/don/2009_12_30/en/index.html

3. Center for Disease Control and Prevention 2010 Updated CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths in the United States, April 2009 –⁠ April 10, 2010. Available: http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm

4. World Health Organization 2009 Human infection with pandemic (H1N1) 2009 virus: updated interim WHO guidance on global surveillance. 10 July 2009. Available: http://www.who.int/csr/resources/publications/swineflu/interim_guidance/en/index.html

5. YazdanbakhshMKremsnerPG 2009 Influenza in Africa. PLoS Med 6 e1000182

6. Van KerkhoveMDMountsAMallSVandemaeleKChamberlandM 2011 Epidemiologic and Virologic Assessment of the 2009 Influenza A (H1N1) Pandemic on Selected Temperate Countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa. Influenza Other Respi Viruses 5 10.1111/j.1750-2659.2011.00249.x

7. World Health Organization 2009 Pandemic (H1N1) 2009 -⁠ update 61 -⁠ Epidemiological Update on the Global Situation and Preliminary Overview of the Southern Hemisphere Winter Influenza Season (as of 6 August 2009). Available: http://www.who.int/csr/don/2009_08_12/en/index.html

8. ShamanJKohnM 2009 Absolute humidity modulates influenza survival, transmission, and seasonality. Proc Natl Acad Sci U S A 106 3243 3248

9. du PrelJBPuppeWGrondahlBKnufMWeiglJA 2009 Are meteorological parameters associated with acute respiratory tract infections? Clin Infect Dis 49 861 868

10. LipsitchMViboudC 2009 Influenza seasonality: lifting the fog. Proc Natl Acad Sci U S A 106 3645 3646

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

12. GrasslyNCFraserC 2008 Mathematical models of infectious disease transmission. Nat Rev Microbiol 6 477 487

13. CauchemezSDonnellyCAReedCGhaniACFraserC 2009 Household transmission of 2009 pandemic influenza A (H1N1) virus in the United States. N Engl J Med 361 2619 2627

14. CauchemezSBhattaraiAMarchbanksTLFaganRPOstroffS 2011 Role of social networks in shaping disease transmission during a community outbreak of 2009 H1N1 pandemic influenza. Proc Natl Acad Sci U S A 108 2825 2830

15. DiekmannOHeesterbeekJARobertsMG 2010 The construction of next-generation matrices for compartmental epidemic models. J R Soc Interface 7 873 885

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

17. MossongJHensNJitMBeutelsPAuranenK 2008 Social contacts and mixing patterns relevant to the spread of infectious diseases. PLoS Med 5 e74

18. SertsouGWilsonNBakerMNelsonPRobertsMG 2006 Key transmission parameters of an institutional outbreak during the 1918 influenza pandemic estimated by mathematical modelling. Theor Biol Med Model 3 38

19. MillsCERobinsJMLipsitchM 2004 Transmissibility of 1918 pandemic influenza. Nature 432 904 906

20. ChowellGAmmonCEHengartnerNWHymanJM 2006 Estimation of the reproductive number of the Spanish flu epidemic in Geneva, Switzerland. Vaccine 24 6747 6750

21. CooperBSPitmanRJEdmundsWJGayNJ 2006 Delaying the international spread of pandemic influenza. PLoS Med 3 e212

22. GaniRHughesHFlemingDGriffinTMedlockJ 2005 Potential impact of antiviral drug use during influenza pandemic. Emerg Infect Dis 11 1355 1362

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

24. FergusonNMCummingsDAFraserCCajkaJCCooleyPC 2006 Strategies for mitigating an influenza pandemic. Nature 442 448 452

25. ChowellGMillerMAViboudC 2008 Seasonal influenza in the United States, France, and Australia: transmission and prospects for control. Epidemiol Infect 136 852 864

26. HsiehYH 2010 Pandemic influenza A (H1N1) during winter influenza season in the southern hemisphere. Influenza Other Respi Viruses 4 187 197

27. LesslerJSantosTDAguileraXBrookmeyerRCummingsDA 2010 H1N1pdm in the Americas. Epidemics 2 132 138

28. PaineSMercerGNKellyPMBandaranayakeDBakerMG 2010 Transmissibility of 2009 pandemic influenza A(H1N1) in New Zealand: effective reproduction number and influence of age, ethnicity and importations. Euro Surveill 15 19591

29. KellyHAMercerGNFieldingJEDowseGKGlassK 2010 Pandemic (H1N1) 2009 influenza community transmission was established in one Australian state when the virus was first identified in North America. PLoS One 5 e11341

30. PedroniEGarciaMEspinolaVGuerreroAGonzalezC 2010 Outbreak of 2009 pandemic influenza A(H1N1), Los Lagos, Chile, April-June 2009. Euro Surveill 15 19456

31. MillerEHoschlerKHardelidPStanfordEAndrewsN 2010 Incidence of 2009 pandemic influenza A H1N1 infection in England: a cross-sectional serological study. Lancet 375 1100 1108

32. DelangueJSalezNNinoveLKiefferAZandottiC Serological study of the 2009 pandemic due to influenza A H1N1 in the metropolitan French population. Clin Microbiol Infect 10.1111/j.1469-0691.2011.03545.x

33. XuCBaiTIulianoADWangMYangL 2011 The Seroprevalence of Pandemic Influenza H1N1 (2009) Virus in China. PLoS One 6 e17919

34. IkonenNStrengellMKinnunenLOsterlundPPirhonenJ 2010 High frequency of cross-reacting antibodies against 2009 pandemic influenza A(H1N1) virus among the elderly in Finland. Euro Surveill 15 19478

35. HancockKVeguillaVLuXZhongWButlerEN 2009 Cross-Reactive Antibody Responses to the 2009 Pandemic H1N1 Influenza Virus. N Engl J Med DOI:10.1056/NEJMoa0906453

36. Van KerkhoveMDAsikainenTBeckerNGBjorgeSDesenclosJC 2010 Studies needed to address public health challenges of the 2009 H1N1 influenza pandemic: insights from modeling. PLoS Med 7 e1000275

37. CowlingBJNgDMIpDKLiaoQLamWW 2010 Community psychological and behavioral responses through the first wave of the 2009 influenza A(H1N1) pandemic in Hong Kong. J Infect Dis 202 867 876

38. LauJTGriffithsSChoiKCTsuiHY 2010 Avoidance behaviors and negative psychological responses in the general population in the initial stage of the H1N1 pandemic in Hong Kong. BMC Infect Dis 10 139

39. IbukaYChapmanGBMeyersLALiMGalvaniAP 2010 The dynamics of risk perceptions and precautionary behavior in response to 2009 (H1N1) pandemic influenza. BMC Infect Dis 10 296

40. SloanCMooreMLHartertT 2011 Impact of pollution, climate, and sociodemographic factors on spatiotemporal dynamics of seasonal respiratory viruses. Clin Transl Sci 4 48 54

41. ShamanJGoldsteinELipsitchM 2011 Absolute humidity and pandemic versus epidemic influenza. Am J Epidemiol 173 127 135

42. CauchemezSValleronAJBoellePYFlahaultAFergusonNM 2008 Estimating the impact of school closure on influenza transmission from Sentinel data. Nature 452 750 754

43. BriandSMountsAChamberlandM 2011 Challenges of global surveillance during an influenza pandemic. Public Health 125 247 256

44. ShamanJPitzerVEViboudCGrenfellBTLipsitchM 2010 Absolute humidity and the seasonal onset of influenza in the continental United States. PLoS Biol 8 e1000316

45. GhaniACBaguelinMGriffinJFlascheSPebodyR 2009 The Early Transmission Dynamics of H1N1pdm Influenza in the United Kingdom. PLoS Curr 1 RRN1130

46. TsaiTFPedottiPHilbertALindertKHohenbokenM 2010 Regional and age-specific patterns of pandemic H1N1 influenza virus seroprevalence inferred from vaccine clinical trials, August-October 2009. Euro Surveill 15 19624

47. ZimmerSMCrevarCJCarterDMStarkJHGilesBM 2010 Seroprevalence following the second wave of Pandemic 2009 H1N1 influenza in Pittsburgh, PA, USA. PLoS One 5 e11601

48. GilbertGLCretikosMAHuestonLDoukasGO'TooleB 2010 Influenza A (H1N1) 2009 antibodies in residents of New South Wales, Australia, after the first pandemic wave in the 2009 southern hemisphere winter. PLoS One 5 e12562

49. KellyHGrantK 2009 Interim analysis of pandemic influenza (H1N1) 2009 in Australia: surveillance trends, age of infection and effectiveness of seasonal vaccination. Euro Surveill 14 19288

50. BakerMGWilsonNHuangQSPaineSLopezL 2009 Pandemic influenza A(H1N1)v in New Zealand: the experience from April to August 2009. Euro Surveill 14 19319