[Show abstract][Hide abstract] ABSTRACT: Influenza and pneumonia combined are the leading causes of death due to infectious diseases in the United States. We describe factors associated with pneumonia among adults hospitalized with influenza.
Through the Emerging Infections Program, we identified adults ≥ 18 years, who were hospitalized with laboratory-confirmed influenza during October 2005 through April 2008, and had a chest radiograph (CXR) performed. Pneumonia was defined as the presence of a CXR infiltrate and either an ICD-9-CM code or discharge summary diagnosis of pneumonia.
Among 4,765 adults hospitalized with influenza, 1392 (29 %) had pneumonia. In multivariable analysis, factors associated with pneumonia included: age ≥ 75 years, adjusted odds ratio (AOR) 1.27 (95 % confidence interval 1.10-1.46), white race AOR 1.24 (1.03-1.49), nursing home residence AOR 1.37 (1.14-1.66), chronic lung disease AOR 1.37 (1.18-1.59), immunosuppression AOR 1.45 (1.19-1.78), and asthma AOR 0.76 (0.62-0.92). Patients with pneumonia were significantly more likely to require intensive care unit (ICU) admission (27 % vs. 10 %), mechanical ventilation (18 % vs. 5 %), and to die (9 % vs. 2 %).
Pneumonia was present in nearly one-third of adults hospitalized with influenza and was associated with ICU admission and death. Among patients hospitalized with influenza, older patients and those with certain underlying conditions are more likely to have pneumonia. Pneumonia is common among adults hospitalized with influenza and should be evaluated and treated promptly.
[Show abstract][Hide abstract] ABSTRACT: During the 2013-14 influenza season in the United States, influenza activity increased through November and December before peaking in late December. Influenza A (H1N1)pdm09 (pH1N1) viruses predominated overall, but influenza B viruses and, to a lesser extent, influenza A (H3N2) viruses also were reported in the United States. This influenza season was the first since the 2009 pH1N1 pandemic in which pH1N1 viruses predominated and was characterized overall by lower levels of outpatient illness and mortality than influenza A (H3N2)-predominant seasons, but higher rates of hospitalization among adults aged 50-64 years compared with recent years. This report summarizes influenza activity in the United States for the 2013-14 influenza season (September 29, 2013-May 17, 2014†) and reports recommendations for the components of the 2014-15 Northern Hemisphere influenza vaccines.
MMWR. Morbidity and mortality weekly report 06/2014; 63(22):483-490.
[Show abstract][Hide abstract] ABSTRACT: Background. Persons with influenza can develop complications that result in hospitalization and death. These are most commonly respiratory-related, but cardiovascular or neurologic complications or exacerbations of underlying chronic medical conditions may also occur. Patterns of complications observed during pandemics may differ from typical influenza seasons, and characterizing variations in influenza-related complications can provide a better understanding of the impact of pandemics and guide appropriate clinical management and planning for the future. Methods. Using a population-based surveillance system, we compared clinical complications using ICD-9 discharge diagnosis codes in adults hospitalized with seasonal influenza (n=5,270) or 2009 pandemic influenza A(H1N1) (H1N1pdm09) (n=4,962). Results. Adults hospitalized with H1N1pdm09 were younger (median age 47 years) than those with seasonal influenza (median: 68 years, p<0.01), and differed in the frequency of certain underlying medical conditions. While there was similar risk for many influenza-associated complications, after controlling for age and type of underlying medical condition adults hospitalized with H1N1pdm09 were more likely to have lower respiratory tract complications, shock/sepsis, and organ failure than those with seasonal influenza. They were also more likely to be admitted to the ICU, require mechanical ventilation, or die. Young adults, in particular, had 2-4 times the risk of severe outcomes from H1N1pdm09 than persons of the same ages with seasonal influenza. Conclusions. While thought of as a relatively mild pandemic, these data highlight the impact of the 2009 pandemic on the risk of severe influenza, especially among younger adults, and the impact this virus may continue to have.
[Show abstract][Hide abstract] ABSTRACT: We challenge the notion that influenza B virus infection is milder than influenza A virus infection by finding similar clinical characteristics and outcomes between adults hospitalized with these two types of influenza. Among patients treated with oseltamivir, length of stay and mortality did not differ by type of virus infection.
[Show abstract][Hide abstract] ABSTRACT: Little information is available describing the epidemiology and clinical characteristics of those <12 months hospitalized with influenza, particularly at a population level.
We used population-based, laboratory-confirmed influenza hospitalization surveillance data from 2003-2012 seasons to describe the impact of influenza by age category (<3, 3 to <6 and 6 to <12 months). Logistic regression was used to explore risk factors for intensive care unit (ICU) admission. Adjusted age specific influenza-associated hospitalization rates were calculated and applied to the number of U.S. infants to estimate national numbers of hospitalizations.
Influenza was associated with an annual average of 6,514 infant hospitalizations (range 1,842- 12,502). Hospitalization rates among infants <3 months were substantially higher than the rate in older infants. Most hospitalizations occurred in otherwise healthy infants (75%) among whom up to 10% were admitted to the ICU and up to 4% had respiratory failure. These proportions were 2-3 times higher in infants with high risk conditions. Infants <6 months were 40% more likely to be admitted to the ICU than older infants. Lung disease (adjusted odds ratio [aOR] 1.80; 95% confidence interval [CI] 1.22, 2.67), cardiovascular disease (aOR 4.16; 95% CI 2.65, 6.53), and neuromuscular disorder (aOR 2.99; 95% CI 1.87, 4.78) were risk factors for ICU admission among all infants.
The impact of influenza on infants, particularly those very young or with high risk conditions, underscore the importance of influenza vaccination, especially among pregnant women and those in contact with young infants not eligible for vaccination.
[Show abstract][Hide abstract] ABSTRACT: Influenza activity in the United States began to increase in mid-November, remained elevated through February 21, 2015, and is expected to continue for several more weeks. To date, influenza A (H3N2) viruses have predominated overall. As has been observed in previous seasons during which influenza A (H3N2) viruses predominated, adults aged ≥65 years have been most severely affected. The cumulative laboratory-confirmed influenza-associated hospitalization rate among adults aged ≥65 years is the highest recorded since this type of surveillance began in 2005. This age group also accounts for the majority of deaths attributed to pneumonia and influenza. The majority of circulating influenza A (H3N2) viruses are different from the influenza A (H3N2) component of the 2014-15 Northern Hemisphere seasonal vaccines, and the predominance of these antigenically and genetically drifted viruses has resulted in reduced vaccine effectiveness. This report summarizes U.S. influenza activity* since September 28, 2014, and updates the previous summary.
MMWR. Morbidity and mortality weekly report 02/2014; 63(7):148-54.
[Show abstract][Hide abstract] ABSTRACT: Seasonal influenza is responsible for more than 200,000 hospitalizations each year in the United States. Although hospital-onset (HO) influenza contributes to morbidity and mortality among these patients, little is known about its overall epidemiology.
We describe patients with HO influenza in the United States during the 2010-2011 influenza season and compare them with community-onset (CO) cases to better understand factors associated with illness.
We identified laboratory-confirmed, influenza-related hospitalizations using the Influenza Hospitalization Surveillance Network (FluSurv-NET), a network that conducts population-based surveillance in 16 states. CO cases had laboratory confirmation ≤ 3 days after hospital admission; HO cases had laboratory confirmation > 3 days after admission.
We identified 172 (2.8%) HO cases among a total of 6,171 influenza-positive hospitalizations. HO and CO cases did not differ by age (P = .22), sex (P = .29), or race (P = .25). Chronic medical conditions were more common in HO cases (89%) compared with CO cases (78%) (P < .01), and a greater proportion of HO cases (42%) than CO cases (17%) were admitted to the intensive care unit (P < .01). The median length of stay after influenza diagnosis of HO cases (7.5 days) was greater than that of CO cases (3 days) (P < .01).
HO cases had greater length of stay and were more likely to be admitted to the intensive care unit or die compared with CO cases. HO influenza may play a role in the clinical outcome of hospitalized patients, particularly among those with chronic medical conditions.
American journal of infection control 10/2013; 42(1). DOI:10.1016/j.ajic.2013.06.018 · 2.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Adults ≥65 years are at greatest risk for influenza hospitalization; ~60% of influenza-related hospitalizations occur in this age group. Hospitalizations are associated with increased disability among the elderly, but no study has specifically examined the impact of influenza hospitalization on community-dwelling older adults with or without co-morbidities. We studied adults ≥65 years living in the community prior to laboratory-confirmed influenza hospitalization to assess whether their need for care increased afterwards.
Methods: We used population-based data collected prospectively through the Influenza Hospitalization Surveillance Network during the 2010-11 season. We described demographic and clinical characteristics of patients with and without co-morbidities; used multivariate analysis to identify independent risk factors for needing higher level of care (defined as admission to nursing home) after discharge.
Results: In the 2010-11 season, there were 1,473 community-dwelling adults ≥65 years hospitalized with influenza (38% were <75 years, 36% between 75-84 years, and 25% were ≥85 years); 53 (3.6%) died during hospitalization. Overall, 11% (157) of hospitalized adults had no identified co-morbidity. Specific co-morbidities varied significantly by age; prevalence of chronic lung and cardiovascular diseases, and neuromuscular disorders increased with age whereas metabolic disorders and asthma decreased. Among those with and without co-morbidities, 17% and 11% respectively required higher level of care after discharge. Independent risk factors for needing higher level of care after discharge included older age (odds ratio [OR] 4.9, 95% confidence interval [CI] 3.2-7.4 among ≥85 years vs. <75 years), neuromuscular disorder (OR 2.5, 95% CI 1.5-4.2) and intensive care during hospitalization (OR 4.4, 95% CI 3.1-6.4).
Conclusion: Influenza hospitalization for community-dwelling elderly patients results in increased need for higher level of care following hospital discharge. This adds to the burden of influenza in this age group, increasing societal and healthcare utilization costs. Annual influenza vaccination and antiviral treatment for those at risk for influenza complications may reduce this burden.
IDWeek 2013 Meeting of the Infectious Diseases Society of America; 10/2013
[Show abstract][Hide abstract] ABSTRACT: Background. Data on the range and severity of influenza-associated complications among children are limited. We describe the frequency and severity of complications in hospitalized children aged <18 years with seasonal influenza (2003-2009) and influenza A(H1N1)pdm09 (2009-2010).
Methods. Population-based surveillance for laboratory-confirmed influenza hospitalizations was conducted among 5.3 million children in 10 states. Complications were identified by ICD-9 codes in medical records.
Results. During 2003-2010, 7,293 children hospitalized with influenza were identified, of whom 6,769 (93%) had complete ICD-9 code data. Among the 6,769 children, the median length of hospitalization was 3 days (interquartile range 2-4), 975 (14%) required intensive care, 359 (5%) had respiratory failure, and 40 (1%) died. The most common complications were pneumonia (28%), asthma exacerbations (793/3616 children >2 years, 22%), and dehydration (21%). Lung abscess/empyema, tracheitis, encephalopathy, bacteremia/sepsis, acute renal failure, and myocarditis were rare (<2%) but associated with median hospitalization >6 days and 48-70% of children required intensive care. Positive bacterial cultures were identified in 2% of children (107/6769); Staphylococcus aureus and Streptococcus pneumoniae were most commonly identified.
Conclusion. Complications add substantially to the burden of hospitalized children with influenza through intensive care requirements and prolonged hospitalization, highlighting the importance of primary prevention with influenza vaccination.
The Journal of Infectious Diseases 08/2013; DOI:10.1093/infdis/jit473 · 5.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background. The Emerging Infections Programs (EIP) network has conducted population-based surveillance for hospitalizations due to laboratory-confirmed influenza among children since 2003, with the network expanding in 2005 to include adults. Methods. From 15 April 2009 through 30 April 2010, the EIP conducted surveillance among 22.1 million people residing in 10 states. Incidence rates per 100 000 population were calculated using US Census Bureau data. Mean historic rates were calculated on the basis of previously published and unpublished EIP data. Results. During the 2009 pandemic of influenza A virus subtype H1N1 infection, rates of hospitalizations due to laboratory-confirmed influenza were 202, 88, 49, 31, 27, 36, 28, and 27 episodes per 100 000 among persons aged < 6 months, 6-23 months, 2-4 years, 5-17 years, 18-49 years, 50-64 years, 65-74 years, and > 75 years, respectively. Comparative mean rates from previous influenza seasons during which EIP conducted surveillance were 153, 53, 20, 6, 4, 8, 20, and 56 episodes per 100 000 among persons aged < 6 months, 6-23 months, 2-4 years, 5-17 years, 18-49 years, 50-64 years, 65-74 years, and > 75 years, respectively. Conclusions. During the pandemic, rates of hospitalization due to laboratory-confirmed influenza among individuals aged 5-17 years and 18-49 years increased 5-fold and 6-fold, respectively, compared with mean rates from previous influenza seasons. Hospitalization rates for other pediatrie and adult age groups increased, compared with mean rates from previous influenza seasons, whereas the rate among individuals aged > 75 years decreased.
The Journal of Infectious Diseases 10/2012; 206(9):1350-1358. DOI:10.2307/41725763 · 5.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Influenza antiviral treatment is recommended for all persons hospitalized with influenza virus infection. During the 2010-2011 influenza season, antiviral treatment of children and adults hospitalized with laboratory-confirmed influenza declined significantly compared with treatment during the 2009 pandemic (children, 56% vs 77%; adults, 77% vs 82%; both P < .01).
[Show abstract][Hide abstract] ABSTRACT: The 2009 influenza pandemic led to guidelines emphasizing antiviral treatment for all persons hospitalized with influenza, including pregnant women. We compared antiviral use among adults hospitalized with influenza before and during the pandemic.
The Emerging Infections Program conducts active population-based surveillance for persons hospitalized with community-acquired, laboratory-confirmed influenza in 10 states. We analyzed data collected via medical record review of patients aged ≥18 years admitted during prepandemic (1 October 2005 through 14 April 2009) and pandemic (15 April 2009 through 31 December 2009) time frames.
Of 5943 adults hospitalized with influenza in prepandemic seasons, 3235 (54%) received antiviral treatment, compared with 4055 (82%) of 4966 during the pandemic. Forty-one (22%) of 187 pregnant women received antiviral treatment in prepandemic seasons, compared with 369 (86%) of 430 during the pandemic. Pregnancy was a negative predictor of antiviral treatment before the pandemic (adjusted odds ratio [aOR], 0.24; 95% confidence interval [CI], .16-.35) but was independently associated with treatment during the pandemic (aOR, 1.97; 95% CI, 1.32-2.96). Antiviral treatment among adults hospitalized >2 days after illness onset increased from 43% before the pandemic to 79% during the pandemic (P < .001).
Antiviral treatment of hospitalized adults increased during the pandemic, especially among pregnant women. This suggests that many clinicians followed published guidance to treat hospitalized adults with antiviral agents. However, compliance with antiviral recommendations could be improved.
The Journal of Infectious Diseases 12/2011; 204(12):1848-56. DOI:10.1093/infdis/jir648 · 5.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Concerns have been raised regarding possible racial-ethnic disparities in 2009 pandemic influenza A (H1N1) (pH1N1) illness severity and health consequences for U.S. minority populations.
Using data from the Centers for Disease Control and Prevention's Behavioral Risk Factor Surveillance System, Emerging Infections Program Influenza-Associated Hospitalization Surveillance, and Influenza-Associated Pediatric Mortality Surveillance, we calculated race-ethnicity-specific, age-adjusted rates of self-reported influenza-like illness (ILI) and pH1N1-associated hospitalizations. We used χ(2) tests to evaluate racial-ethnic disparities in ILI-associated health care-seeking behavior and pH1N1 hospitalization. To evaluate pediatric deaths, we compared racial-ethnic proportions of deaths against U.S. population distributions.
Prevalence of self-reported ILI was lower among Hispanics (6.5%), higher among American Indians/Alaska Natives (16.2%), and similar among non-Hispanic blacks (7.7%) compared with non-Hispanic whites (8.5%). No racial-ethnic differences were identified in ILI-associated health care-seeking behavior. Age-adjusted pH1N1-associated Emerging Infections Program hospitalization rates were higher among all minority populations (range: 8.1-10.9/100,000 population) compared with non-Hispanic whites (3.0/100,000). The proportion of pH1N1-associated pediatric deaths was higher than expected among Hispanics (31%) and lower than expected among non-Hispanic whites (45%) given the proportions of the U.S. population they comprise (22% and 58%, respectively).
Racial-ethnic disparities in pH1N1-associated hospitalizations and pediatric deaths were identified. Vaccination remains the primary intervention for preventing influenza.
Annals of epidemiology 08/2011; 21(8):623-30. DOI:10.1016/j.annepidem.2011.03.002 · 2.15 Impact Factor