The 2009 pandemic influenza A (H1N1) virus was accompanied by high morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with documented 2009 influenza A (H1N1) virus admitted to a reference chest hospital, the disease outcome, and risk factors associated with ICU admission.
METHODS:
We assessed 109 subjects admitted to the respiratory infection unit of a hospital for chest disease with signs and symptoms of the 2009 influenza A (H1N1) virus between April 2009 and December 2010. Demographic data, comorbidities, clinical signs and symptoms, laboratory tests, radiographic findings, treatment, and final outcomes were all recorded. Factors associated with severe disease requiring ICU admission were determined.
RESULTS:
Ninety subjects (82.5%) had laboratory-confirmed 2009 influenza A (H1N1). Sixty-four percent of these subjects had pneumonia on admission, 26% had respiratory failure, and 11% required care in the ICU. Dyspnea and the presence of infiltrates on chest x-rays were the most common signs among the subjects with H1N1. All subjects were treated with antiviral therapy, and 75% received antibiotic treatment based on their clinical and laboratory findings. The predictive factors of ICU admission were severe hypoxemia and lymphocytosis.
CONCLUSIONS:
The outcome of subjects with influenza A (H1N1) virus infection was influenced by the severity of the disease on admission, the subjects' underlying conditions, and complications during hospitalization.
LytrasT, TheocharopoulosG, TsiodrasS, MentisA, PanagiotopoulosT, BonovasS, Influenza Surveillance Report Group. Enhanced surveillance of influenza A(H1N1)v in Greece during the containment phase. Euro Surveill, 2009; 14(29):pii 19275.
3.
PanagiotopoulosT, BonovasS, DanisK, IliopoulosD, DedoukouX, PavliA, et al. Cluster of new influenza A(H1N1) cases in travellers returning from Scotland to Greece–community transmission within the European Union?. Euro Surveill, 2009; 14(21):pii 19226.
4.
AthanasiouM, LytrasT, SpalaG, TriantafyllouE, GkolfinopoulouK, TheocharopoulosG, et al. Fatal cases associated with pandemic influenza A (H1N1) reported in Greece. PLoS Curr, 2010; 2:RRN1194.
5.
Centers for Disease Control and Prevention (CDC). Deaths and hospitalizations related to 2009 pandemic influenza A (H1N1)–Greece, May 2009–February 2010. MMWR Morb Mortal Wkly Rep, 2010; 59(22):682–686.
6.
SypsaV, BonovasS, TsiodrasS, BakaA, EfstathiouP, MallioriM, et al. Estimating the disease burden of 2009 pandemic influenza A(H1N1) from surveillance and household surveys in Greece. PLoS ONE, 2011; 6(6):e20593.
7.
NikolopoulosG, BagosP, LytrasT, BonovasS. An ecological study of the determinants of differences in 2009 pandemic influenza mortality rates between countries in Europe. PLoS ONE, 2011; 6(5):e19432.
Centers for Disease Control and Prevention. Interim guidance on case definitions to be used for investigations of novel influenza A (H1N1)v virus cases. http://www.cdc.gov/h1n1flu/casedef.htm. Accessed July 16, 2014.
11.
WardCL, DempseyMH, RingCJ, KempsonRE, ZhangL, GorD, et al. Design and performance testing of quantitative real time PCR assays for influenza A and B viral load measurement. J Clin Virol, 2004; 29(3):179–188.
12.
CharlsonME, PompeiP, AlesKL, MacKenzieCR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis, 1987; 40(5):373–383.
13.
SmithJR, RaynerCR, DonnerB, WollenhauptM, KlumppK, DutkowskiR. Oseltamivir in seasonal, pandemic, and avian influenza: a comprehensive review of 10-years clinical experience. Adv Ther, 2011; 28(11):927–959.
14.
Van KerkhoveMD, VandemaeleKA, ShindeV, Jaramillo-GutierrezG, KoukounariA, DonnellyCA, et al. Risk factors for severe outcomes following 2009 influenza A (H1N1) infection: a global pooled analysis. PLoS Med, 2011; 8(7):e1001053.
15.
CardeñosaN, RodésA, FolliaN, PlasenciaE, LafuenteS, AriasC, et al. Epidemiological analysis of severe hospitalized 2009 pandemic influenza A (H1N1) cases in Catalonia, Spain. Hum Vaccin, 2011; 7(Suppl):226–229.
16.
FuhrmanC, BonmarinI, PatyAC, DuportN, ChironE, LucasE, et al. Severe hospitalised 2009 pandemic influenza A(H1N1) cases in France, 1 July–15 November 2009. Euro Surveill, 2010; 15(2); pii 19463.
17.
HancockK, VeguillaV, LuX, ZhongW, ButlerEN, SunH, et al. Cross-reactive antibody responses to the 2009 pandemic H1N1 influenza virus. N Engl J Med, 2009; 361(20):1945–1952.
18.
LeeVJ, TayJK, ChenMI, PhoonMC, XieML, WuY, et al. Inactivated trivalent seasonal influenza vaccine induces limited cross-reactive neutralizing antibody responses against 2009 pandemic and 1934 PR8 H1N1 strains. Vaccine, 2010; 28(42):6852–6857.
19.
IorioAM, CamilloniB, LepriE, NeriM, BasileoM, AzziA. Induction of cross-reactive antibodies to 2009 pandemic H1N1 influenza virus (pH1N1) after seasonal vaccination (Winter 2003/04 and 2007/08). Proc Vaccinol, 2011; 4:50–58.
Writing Committee of the Second World Health Organization Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus, Abdel-GhafarAN, ChotpitayasunondhT, GaoZ, HaydenFG, NguyenDH, et al. Update on avian influenza A (H5N1) virus infection in humans. N Engl J Med, 2008; 358(3):261–273.
22.
Echevarría-ZunoS, Mejía-AranguréJM, Mar-ObesoAJ, Grajales-MuñizC, Robles-PérezE, González-LeónM, et al. Infection and death from influenza A H1N1 virus in Mexico: a retrospective analysis. Lancet, 2009; 374(9707):2072–2079.
23.
MertzD, KimTH, JohnstoneJ, LamPP, ScienceM, KusterSP, et al. Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis. BMJ, 2013; 347:f5061.
24.
DonaldsonLJ, RutterPD, EllisBM, GreavesFE, MyttonOT, PebodyRG, YardleyIE. Mortality from pandemic A/H1N1 2009 influenza in England: public health surveillance study. BMJ, 2009; 339:b5213.
25.
LouieJK, AcostaM, WinterK, JeanC, GavaliS, SchechterR, et al. Factors associated with death or hospitalization due to pandemic 2009 influenza A(H1N1) infection in California. JAMA, 2009; 302(17):1896–902.
26.
KumarA, ZarychanskiR, PintoR, CookDJ, MarshallJ, LacroixJ, et al. Critically ill patients with 2009 influenza A (H1N1) infection in Canada. JAMA, 2009; 302(17):1872–1879.
27.
ANZIC Influenza Investigators, WebbSA, PettiläV, SeppeltI, BellomoR, BaileyM, et al. Critical care services and 2009 H1N1 influenza in Australia and New Zealand. N Engl J Med, 2009; 361(20):1925–1934.
28.
CorderoE, AydilloT, FariñasMC, Paño-PardoJR, PachónJ, ViasusD, et al. Immunosupressed patients with pandemic influenza A 2009 (H1N1) virus infection. Eur J Clin Microbiol Infect Dis, 2012; 31(4):547–556.
29.
McKennaJJ, BramleyAM, SkarbinskiJ, FryAM, FinelliL, JainS, et al. Asthma in patients hospitalized with pandemic influenza A(H1N1)pdm09 virus infection–United States, 2009. BMC Infect Dis, 2013; 13:57.
30.
de Miguel-DiezJ, Carrasco-GarridoP, Hernández-BarreraV, Rodríguez-RodríguezP, Puente-MaestuL, de MiguelAG, et al. Hospitalizations from pandemic influenza (pH1N1) infections among patients with asthma or COPD in Spain. J Infect, 2012; 65(1):95–98.
31.
AkinbamiLJ, MoormanJE, LiuX. Asthma prevalence, health care use, and mortality: United States 2005-2009. Natl Health Stat Rep, 2011; 32:1–14. http://www.cdc.gov/nchs/data/nhsr/nhsr032.pdf. Accessed July 16, 2014.
32.
Nguyen-Van-TamJS, OpenshawPJ, HashimA, GaddEM, LimWS, SempleMG, et al. Risk factors for hospitalization and poor outcome with pandemic A/H1N1 influenza: United Kingdom first wave (May–September 2009). Thorax, 2010; 65(7):645–651.
33.
CullenG, MartinJ, O'DonnellJ, BolandM, CannyM, KeaneE, et al. Surveillance of the first 205 confirmed hospitalised cases of pandemic H1N1 influenza in Ireland, 28 April–3 October 2009. Euro Surveill, 2009; 14(44):pii 19389.
34.
DenholmJT, GordonCL, JohnsonPD, HewagamaSS, StuartRL, AboltinsC, et al. Hospitalised adult patients with pandemic (H1N1) 2009 influenza in Melbourne, Australia. MJA, 2010; 192(2):84–86.
35.
Santa-Olalla PeraltaP, Cortes-GarcíaM, Vicente-HerreroM, Castrillo-VillamandosC, Arias-BohigasP, Pachon-del AmoI, et al. Risk factors for disease severity among hospitalised patients with 2009 pandemic influenza A (H1N1) in Spain, April–December 2009. Euro Surveill, 2010; 15(38):pii 19667.
36.
SubramonyH, LaiFY, AngLW, CutterJL, LimPL, JamesL. An epidemiological study of 1348 cases of pandemic H1N1 influenza admitted to Singapore hospitals from July to Septembeer 2009. Ann Acad Med Singapore, 2010; 39(4):283–288.
KokJ, BlythCC, FooH, BaileyMJ, PilcherDV, WebbSA, et al. Viral pneumonitis is increased in obese patients during the first wave of pandemic A(H1N1) 2009 virus. PLoS ONE, 2013; 8(2):e55631.
39.
Gutiérrez-CuadraM, González-FernándezJL, Rodríguez-CundinP, Fariñas-ÁlvarezC, San JuanMV, ParraJA, et al. Clinical characteristics and outcome of patients with pandemic 2009 influenza A(H1N1)v virus infection admitted to hospitals with different levels of health-care. Rev Esp Quimioter, 2012; 25(1):56–64.
40.
CillónizC, EwigS, MenéndezR, FerrerM, PolverinoE, ReyesS, et al. Bacterial co-infection with H1N1 infection in patients admitted with community acquired pneumonia. J Infect, 2012; 65(3):223–230.
41.
MorensDM, TaubenbergerJK, FauciAS. Predominant role of bacterial pneumonia as a cause of death in pandemic influenza: implications for pandemic influenza preparedness. J Infect Dis, 2008; 198(7):962–970.
42.
ChampunotR, TanjathamS, KerdsinA, PuangpatraP, WangsaiS, TreebuphachatsakulP, et al. Impact of pandemic influenza (H1N1) virus-associated community-acquired pneumonia among adults in a tertiary hospital in Thailand. Jpn J Infect Dis, 2010; 63(4):251–256.
43.
WongSM, BernuiM, ShenH, AkerleyBJ. Genome-wide fitness profiling reveals adaptations required by Haemophilus in coinfection with influenza A virus in the murine lung. Proc Natl Acad Sci USA, 2013; 110(38):15413–15418.
44.
JamiesonAM, PasmanL, YuS, GamradtP, HomerRJ, DeckerT, MedzhitovR. Role of tissue protection in lethal respiratory viral-bacterial coinfection. Science, 2013; 340(6137):1230–1234.
45.
ViasusD, Paño-PardoJR, PachónJ, RieraM, López-MedranoF, PayerasA, et al. Timing of oseltamivir administration and outcomes in hospitalized adults with pandemic 2009 influenza A (H1N1) virus infection. Chest, 2011; 140(4):1025–1032.
46.
FioreAE, FryA, ShayD, GubarevaL, BreseeJS, UyekiTM, Centers for Disease Control and Prevention (CDC). Antiviral agents for the treatment and chemoprophylaxis of influenza—recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep, 2011; 60(1):1–24.
47.
RodríguezA, DíazE, Martín-LoechesI, SandiumengeA, CanadellL, DíazJJ, et al. Impact of early oseltamivir treatment on outcome in critically ill patients with 2009 pandemic influenza A. J Antimicrob Chemother, 2011; 66(5):1140–1149.
48.
KawaiN, IkematsuH, TanakaO, MatsuuraS, MaedaT, YamauchiS, et al. Comparison of the clinical symptoms and the effectiveness of neuraminidase inhibitors for patients with pandemic influenza H1N1 2009 or seasonal H1N1 influenza in the 2007-2008 and 2008–2009 seasons. J Infect Chemother, 2011; 17(3):375–381.
49.
TrivellinV, GandiniV, NespoliL. Low adherence to influenza vaccination campaigns: is the H1N1 virus pandemic to be blamed?. Ital J Pediatr, 2011; 10:37:54.
50.
Centers for Disease Control and Prevention. Interim results: state-specific Influenza A (H1N1) 2009 monovalent vaccination coverage–United States, October 2009–January 2010. MMWR Morb Mortal Wkly Rep, 2010; 59(12):363–368.
51.
TsiodrasS, SypsaV, HatzakisA. The vaccination campaign against 2009 pandemic influenza A (H1N1) and its continued importance in view of the uncertainty surrounding the risk associated with the pandemic. Euro Surveill, 2010; 15(3):pii 19468.
52.
SypsaV, LivaniosT, PsichogiouM, MallioriM, TsiodrasS, NikolakopoulosI, HatzakisA. Public perceptions in relation to intention to receive pandemic influenza vaccination in a random population sample: evidence from a cross-sectional telephone survey. Euro Surveill, 2009; 14(49):pii 19437.
