Influenza-Associated Pneumonia Among Hospitalized Patients With 2009 Pandemic Influenza A (H1N1) Virus-United States, 2009

Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Clinical Infectious Diseases (Impact Factor: 8.89). 03/2012; 54(9):1221-9. DOI: 10.1093/cid/cis197
Source: PubMed


Pneumonia was a common complication among hospitalized patients with 2009 pandemic influenza A H1N1 [pH1N1] in the United States in 2009.
Through 2 national case series conducted during spring and fall of 2009, medical records were reviewed. A pneumonia case was defined as a hospitalized person with laboratory-confirmed pH1N1 virus and a chest radiographic report consistent with pneumonia based on agreement among 3 physicians.
Of 451 patients with chest radiographs performed, 195 (43%) had pneumonia (spring, 106 of 237 [45%]; fall, 89 of 214 [42%]). Compared with 256 patients without pneumonia, these 195 patients with pneumonia were more likely to be admitted to the intensive care unit (52% vs 16%), have acute respiratory distress syndrome (ARDS; 26% vs 2%), have sepsis (18% vs 3%), and die (17% vs 2%; P < .0001). One hundred eighteen (61%) of the patients with pneumonia had ≥1 underlying condition. Bacterial infections were reported in 13 patients with pneumonia and 2 patients without pneumonia. Patients with pneumonia, when compared with patients without pneumonia, were equally likely to receive influenza antiviral agents (78% vs 79%) but less likely to receive antiviral agents within ≤2 days of illness onset (28% vs 50%; P < .0001).
Hospitalized patients with pH1N1 and pneumonia were at risk for severe outcomes including ARDS, sepsis, and death; antiviral treatment was often delayed. In the absence of accurate pneumonia diagnostics, patients hospitalized with suspected influenza and lung infiltrates on chest radiography should receive early and aggressive treatment with antibiotics and influenza antiviral agents.

Full-text preview

Available from:
  • Source
    • "Both intravenous zanamivir and oseltamivir use were associated with lower aHR for death when modeled as timedependent exposures. The observed mortality rate was lower but consistent with retrospective cohort studies of critically ill hospitalized patients with influenza during this time period202122232425. For example, in critically ill patients with 2009 influenza A/H1N1pdm09, a 50% ICU mortality rate has been reported[25], and a California-cohort study in 1950 patients reported a 25% mortality rate with neuraminidase treatment (median time from symptom onset, 4 days) and a 42% mortality rate without treatment[26]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: IVZ is a neuraminidase inhibitor in development for treatment of hospitalized patients with severe influenza. Methods: Hospitalized symptomatic patients with local laboratory-confirmed influenza within 7 days of illness onset received IVZ for 5-10 days at 600 mg twice daily adjusted for renal impairment or renal replacement therapy (RRT). Patients were assessed during treatment and for 23 days after treatment for safety and virology. Serial serum PK sampling was done with the first and a repeat IVZ dose ( NCT01014988). Results: 130 adults (56 female, 4 pregnant) from 8 countries were enrolled from November 2009 to August 2011. Median age was 48 years (range, 18-94), 75% were Caucasian, 33% were obese (BMI>30), 80% had received oseltamivir (median, 2 days). 75% had chronic medical conditions (respiratory 32%, immunocompromised 25%). Median time from influenza symptom onset to IVZ was 4.5 days (range, 1-7). At baseline, 89% had an infiltrate on chest X-ray, 48% required mechanical ventilation (MV) and 5% RRT. During the study 60% required MV, 83% required ICU care, and 3% ECMO. Median hospital stay was 15 days (range, 1-133) and median ICU stay was 11.5 days (range, 1-104). 14 and 28-day cumulative mortality was 13% and 17%. 94% of subjects had influenza A (71% H1N1pdm09, 12% H3N2, 11% subtype unknown), 2% influenza B and 4% not typed. Of 93 subjects with positive baseline nasopharyngeal PCR, median baseline viral load was 5.34 log10 c/mL (range, 2.86-8.17) and median change at Day 3 was –1.42 log10 c/mL (range, –3.38 to +1.08). Steady state PK data from 76 subjects with normal renal function (mean Cmax=35.3 µg/mL, AUC=90.3 h*µg/mL, Cmin= 0.82 µg/mL) were as expected for 600 mg and above the mean reported influenza IC50 (0.08-1.01 ng/mL) for IVZ. 85% of subjects experienced adverse events (AEs), 44% had a grade 3 or 4 AE and 34% a serious AE. 13% met protocol defined liver-event criteria (8% on-treatment, 5% post-treatment) with no correlation to PK. There were no clinically significant trends in labs, vital signs or ECGs. Potential causality of AEs was confounded by severity of illness and concomitant medications. Conclusion: No significant safety signals attributable to IVZ were identified in this population with severe influenza. A Phase 3 study of IVZ is underway.
    Full-text · Conference Paper · Oct 2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Shortly after the advent of severe acute respiratory syndrome and the avian influenza, the emergence of the influenza A(H1N1)2009 pandemic caused significant vibrations to the public health authorities and stressed the health systems worldwide. We sought to investigate whether this experience has altered our knowledge and our current and future practice on the management of severe acute respiratory infections (SARI) and community-acquired pneumonia. A changing epidemiology was demonstrated, with obesity and pregnancy beyond established risk groups for influenza A, other clinical syndromes beyond primary viral pneumonia, possible coinfections by other viral beyond bacterial pathogens and a disappointing performance of all available severity assessment tools. On the treatment topic, accumulating evidence suggesting worse outcomes argues against the use of corticosteroids, but some noninvasive ventilating modalities require further assessment. The recent influenza A(H1N1)2009 pandemic has highlighted our weaknesses relating to the diagnosis and assessment of severity of SARI, compromising early treatment and ultimate outcomes; further research based on this experience will help to improve prognosis and boost our future preparedness. An important message is the necessity of international collaboration for the rapid dissemination of locally acquired knowledge.
    No preview · Article · Jul 2012 · Current opinion in critical care
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The 2009 H1N1 outbreak provides an opportunity to learn about the strengths and weaknesses of current U.S. public health surveillance systems and to identify implications for measuring public health emergency preparedness. We adopted a "triangulation" approach in which multiple contemporary data sources, each with different expected biases, are compared to identify time patterns that are likely to reflect biases versus those that are more likely to be indicative of actual infection rates. This approach is grounded in the understanding that surveillance data are the result of a series of decisions made by patients, health care providers, and public health professionals about seeking and providing health care and about reporting cases to health authorities. Although limited by the lack of a gold standard, this analysis suggests that children and young adults are over-represented in many pH1N1 surveillance systems, especially in the spring wave. In addition, the nearly two-month delay between the Northeast and the South in the Fall peak in some surveillance data seems to at least partially reflect regional differences in concerns about pH1N1 rather than real differences in pH1N1 infection rates. Although the extent of the biases suggested by this analysis cannot be known precisely, the analysis identifies underlying problems with surveillance systems--in particular their dependence on patient and provider behavior, which is influenced by a changing information environment--that could limit situational awareness in future public health emergencies. To improve situational awareness in future health emergencies, population-based surveillance systems such as telephone surveys of representative population samples and seroprevalence surveys in well-defined population cohorts are needed.
    Full-text · Article · Aug 2012 · PLoS ONE
Show more