Epidemiology of 2009 Pandemic Influenza A (H1N1) in the United States

Jhung, Michael A.; Swerdlow, David L.; Olsen, Sonja J.; Jernigan, Daniel B.; Biggerstaff, Matthew; Kamimoto, Laurie; Kniss, Krista; Reed, Carrie; Fry, Alicia M.; Brammer, Lynnette; Gindler, Jacqueline; Gregg, William J.; Bresee, Joseph S.; Finelli, Lyn

doi:10.1093/cid/ciq008

Cited by 160 publications

(170 citation statements)

References 38 publications

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“…Our new estimate of 4·8 excess R&C deaths per 100 000 (95% CI: 3·27–6·40) using traditional excess mortality approaches fits well in the range of previous estimates. Further, the signature age shift of deaths toward younger ages reported here echoes previous studies 6, 13, 14…”

Section: Discussionsupporting

confidence: 91%

“…This ratio compares favorably with diagnostic propensity in Mexico (1/7), but is not as high as in France (1/2) or the United Kingdom (1/4) 16, 18, 20. Further, the age distribution of pandemic‐related deaths is in strong agreement between excess mortality models and laboratory‐confirmed deaths, with 79% (respectively, 85%) of deaths in persons under 65 14. Precise estimates of pandemic excess mortality burden are difficult to obtain for seniors, however, due to the mild nature of the 2009–10 season in this age group.…”

Section: Discussionmentioning

confidence: 77%

“…In the United States, 2096 laboratory‐confirmed deaths were reported from August 30, 2009–April 6, 2010 14. Our estimate of 14 800 excess R&C deaths attributable to the pandemic suggests that 1 in ~7 excess deaths were captured by laboratory surveillance.…”

Section: Discussionmentioning

confidence: 86%

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Mortality burden of the 2009‐10 influenza pandemic in the United States: improving the timeliness of influenza severity estimates using inpatient mortality records

Charu

Simonsen

Lustig³

et al. 2013

Influenza Resp Viruses

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BackgroundDelays in the release of national vital statistics hinder timely assessment of influenza severity, especially during pandemics. Inpatient mortality records could provide timelier estimates of influenza‐associated mortality.MethodsWe compiled weekly age‐specific deaths for various causes from US State Inpatient Databases (1990–2010) and national vital statistics (1990–2009). We calculated influenza‐attributable excess deaths by season based on Poisson regression models driven by indicators of respiratory virus activity, seasonality, and temporal trends.ResultsExtrapolations of excess mortality from inpatient data fell within 11% and 17% of vital statistics estimates for pandemic and seasonal influenza, respectively, with high year‐to‐year correlation (Spearman's rho = 0·87–0·90, P < 0·001, n = 19). We attribute 14 800 excess respiratory and cardiac deaths (95% CI: 10 000–19 650) to pandemic influenza activity during April 2009–April 2010, 79% of which occurred in people under 65 years.ConclusionsModeling inpatient mortality records provides useful estimates of influenza severity in advance of national vital statistics release, capturing both the magnitude and the age distribution of pandemic and epidemic deaths. We provide the first age‐ and cause‐specific estimates of the 2009 pandemic mortality burden using traditional ‘excess mortality’ methods, confirming the unusual burden of this virus in young populations. Our inpatient‐based approach could help monitor mortality trends in other infectious diseases.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 77%

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Mortality burden of the 2009‐10 influenza pandemic in the United States: improving the timeliness of influenza severity estimates using inpatient mortality records

Charu

Simonsen

Lustig³

et al. 2013

Influenza Resp Viruses

View full text Add to dashboard Cite

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“…Basic patient demographics and underlying risk factors for severe influenza are provided ( Table 1). The median age in our cohort was 28.5 years (range: 2 mo to 101 yr), similar to the age distribution observed during the 2009-2010 influenza season (8).…”

Section: High Intensive Care Unit Admission Rate For 2013-2014 Influesupporting

confidence: 84%

High Intensive Care Unit Admission Rate for 2013–2014 Influenza Is Associated with a Low Rate of Vaccination

Catania

Que

Govert

et al. 2014

Am J Respir Crit Care Med

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“…An estimated 2,500-6,000 pH1N1-related deaths occurred between April and October 17, 2009 in the United States (www.cdc.gov/h1n1flu/estimates/ April_March_13.htm). The pH1N1 virus was a triple-reassortant virus that had not been reported previously in animals or humans (1), and several epidemiologic characteristics differed substantially between this and other circulating H1N1 viruses. pH1N1-associated hospitalization rates and mortality among the elderly population were lower than those for seasonal influenza and higher for children and young adults (1); they also were higher for Hispanic, African American, Pacific Islander and American Indian/Alaska Native populations than for those of European/Caucasian descent (2)(3)(4)(5)(6)(7)(8)(9)(10).…”

mentioning

confidence: 78%

HLA targeting efficiency correlates with human T-cell response magnitude and with mortality from influenza A infection

Hertz

Oshansky

Roddam

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Experimental and computational evidence suggests that HLAs preferentially bind conserved regions of viral proteins, a concept we term "targeting efficiency," and that this preference may provide improved clearance of infection in several viral systems. To test this hypothesis, T-cell responses to A/H1N1 (2009) were measured from peripheral blood mononuclear cells obtained from a household cohort study performed during the 2009-2010 influenza season. We found that HLA targeting efficiency scores significantly correlated with IFN-γ enzyme-linked immunosorbent spot responses (P = 0.042, multiple regression). A further population-based analysis found that the carriage frequencies of the alleles with the lowest targeting efficiencies, A*24, were associated with pH1N1 mortality (r = 0.37, P = 0.031) and are common in certain indigenous populations in which increased pH1N1 morbidity has been reported. HLA efficiency scores and HLA use are associated with CD8 T-cell magnitude in humans after influenza infection. The computational tools used in this study may be useful predictors of potential morbidity and identify immunologic differences of new variant influenza strains more accurately than evolutionary sequence comparisons. Population-based studies of the relative frequency of these alleles in severe vs. mild influenza cases might advance clinical practices for severe H1N1 infections among genetically susceptible populations.MHC | HLA association | T-cell epitope | Native American

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Epidemiology of 2009 Pandemic Influenza A (H1N1) in the United States

Cited by 160 publications

References 38 publications

Mortality burden of the 2009‐10 influenza pandemic in the United States: improving the timeliness of influenza severity estimates using inpatient mortality records

Mortality burden of the 2009‐10 influenza pandemic in the United States: improving the timeliness of influenza severity estimates using inpatient mortality records

High Intensive Care Unit Admission Rate for 2013–2014 Influenza Is Associated with a Low Rate of Vaccination

HLA targeting efficiency correlates with human T-cell response magnitude and with mortality from influenza A infection

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