Publication Date:
2009-05-13
Description:
A novel influenza A (H1N1) virus has spread rapidly across the globe. Judging its pandemic potential is difficult with limited data, but nevertheless essential to inform appropriate health responses. By analyzing the outbreak in Mexico, early data on international spread, and viral genetic diversity, we make an early assessment of transmissibility and severity. Our estimates suggest that 23,000 (range 6000 to 32,000) individuals had been infected in Mexico by late April, giving an estimated case fatality ratio (CFR) of 0.4% (range: 0.3 to 1.8%) based on confirmed and suspected deaths reported to that time. In a community outbreak in the small community of La Gloria, Veracruz, no deaths were attributed to infection, giving an upper 95% bound on CFR of 0.6%. Thus, although substantial uncertainty remains, clinical severity appears less than that seen in the 1918 influenza pandemic but comparable with that seen in the 1957 pandemic. Clinical attack rates in children in La Gloria were twice that in adults (〈15 years of age: 61%; 〉/=15 years: 29%). Three different epidemiological analyses gave basic reproduction number (R0) estimates in the range of 1.4 to 1.6, whereas a genetic analysis gave a central estimate of 1.2. This range of values is consistent with 14 to 73 generations of human-to-human transmission having occurred in Mexico to late April. Transmissibility is therefore substantially higher than that of seasonal flu, and comparable with lower estimates of R0 obtained from previous influenza pandemics.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735127/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735127/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fraser, Christophe -- Donnelly, Christl A -- Cauchemez, Simon -- Hanage, William P -- Van Kerkhove, Maria D -- Hollingsworth, T Deirdre -- Griffin, Jamie -- Baggaley, Rebecca F -- Jenkins, Helen E -- Lyons, Emily J -- Jombart, Thibaut -- Hinsley, Wes R -- Grassly, Nicholas C -- Balloux, Francois -- Ghani, Azra C -- Ferguson, Neil M -- Rambaut, Andrew -- Pybus, Oliver G -- Lopez-Gatell, Hugo -- Alpuche-Aranda, Celia M -- Chapela, Ietza Bojorquez -- Zavala, Ethel Palacios -- Guevara, Dulce Ma Espejo -- Checchi, Francesco -- Garcia, Erika -- Hugonnet, Stephane -- Roth, Cathy -- WHO Rapid Pandemic Assessment Collaboration -- G0600719/Medical Research Council/United Kingdom -- GR082623MA/Wellcome Trust/United Kingdom -- U54 GM088491/GM/NIGMS NIH HHS/ -- Biotechnology and Biological Sciences Research Council/United Kingdom -- Medical Research Council/United Kingdom -- New York, N.Y. -- Science. 2009 Jun 19;324(5934):1557-61. doi: 10.1126/science.1176062. Epub 2009 May 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, Faculty of Medicine, Norfolk Place, London W2 1PG, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19433588" target="_blank"〉PubMed〈/a〉
Keywords:
*Disease Outbreaks
;
Global Health
;
Humans
;
*Influenza A Virus, H1N1 Subtype
;
Influenza, Human/*epidemiology/mortality/transmission/virology
;
Mexico/epidemiology
;
Molecular Sequence Data
;
Travel
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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