scholarly journals Hospitalisation associated with the 2009 H1N1 pandemic and seasonal influenza in Hong Kong, 2005 to 2010

2012 ◽  
Vol 17 (45) ◽  
Author(s):  
L Yang ◽  
X L Wang ◽  
K P Chan ◽  
P H Cao ◽  
H Y Lau ◽  
...  
Keyword(s):  
Hong Kong ◽  
Chronic Diseases ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Influenza ◽  
Morbidity Burden ◽  
Increased Risk ◽  
Influenza A H1n1 ◽  
2009 H1n1

Reliable estimates of the morbidity burden caused by the 2009 pandemic influenza (pH1N1) are important for assessing the severity of the pandemic. Poisson regression models were fitted to weekly numbers of cause-specific hospitalisation in Hong Kong from 2005 to 2010. Excess hospitalisation associated with the 2009 pandemic and seasonal influenza was derived from the model by incorporating the proxy variables of weekly proportions of specimens positive for the pandemic influenza A(H1N1)pdm09, seasonal influenza A (subtypes H3N2 and H1N1) and B viruses. Compared with seasonal influenza, pH1N1 influenza was associated with higher hospitalisation rates for acute respiratory disease (ARD) among children younger than 18 years and adults aged between 18 and 64 years, but among the elderly aged 65 years and older the hospitalisation rates were lower for pH1N1 than for seasonal H3N2 and H1N1 influenza. Hospitalisation rates for chronic diseases associated with pH1N1 influenza were generally higher than those associated with seasonal influenza. The reported hospitalised cases with laboratory-confirmed pandemic infections accounted for only 16% of pH1N1 influenza-associated hospitalisations for ARD in the age group 75 years and older, and 5?66% of hospitalisations for chronic diseases in those older than 40 years. The 2009 H1N1 influenza pandemic was associated with a dramatically increased risk of hospitalisation among children and young adults. The morbidity burden of pandemic was underreported in old people and in those with chronic conditions.

scholarly journals Contemporary Seasonal Influenza A (H1N1) Virus Infection Primes for a More Robust Response To Split Inactivated Pandemic Influenza A (H1N1) Virus Vaccination in Ferrets

2010 ◽  
Vol 17 (12) ◽  
pp. 1998-2006 ◽  
Author(s):  
Ali H. Ellebedy ◽  
Thomas P. Fabrizio ◽  
Ghazi Kayali ◽  
Thomas H. Oguin ◽  
Scott A. Brown ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Virus ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Inactivated Vaccine ◽  
H1n1 Influenza Virus ◽  
Influenza A H1n1

ABSTRACT Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8+ cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.

Increased Severity of Pandemic H1N1 Influenza in Children and Young Adults with Sickle Cell Disease.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 264-264 ◽  
Author(s):  
John J. Strouse ◽  
Martha Amoako ◽  
Megan Reller ◽  
James F. Casella
Keyword(s):  
Young Adults ◽  
Intensive Care ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Influenza ◽  
Johns Hopkins Hospital ◽  
Acute Chest Syndrome ◽  
Increased Risk ◽  
Children And Young Adults

Abstract Abstract 264 Background: Admission for influenza is more than 50 times more frequent in children with sickle cell disease (SCD) than in the general population. H1N1 influenza, a novel influenza A virus of swine origin, began circulating in the United States in the spring of 2009 and has now been detected in over 170 countries. H1N1 influenza has been reported to cause more severe illness in children and young adults than seasonal influenza. To compare the relative severity of H1N1 influenza vs. seasonal influenza A and B in young persons with SCD, we compared the clinical characteristics and complications associated with these infections in patients seen at our tertiary care hospital. Methods: We defined a case as laboratory-confirmed influenza infection with influenza A or B in a patient aged 0–21 years with SCD who was evaluated at Johns Hopkins Hospital from 1 September 1993 to 31 July 2009. Through July 2006, we searched the discharge and billing databases for Johns Hopkins Hospital to identify those with SCD and laboratory testing for respiratory infections. Thereafter, we prospectively identified cases through divisional records. We confirmed the diagnosis of influenza by review of microbiology results in each patient's paper and/or electronic medical record. All respiratory samples positive for influenza A after 1 May 2009 were tested for pandemic H1N1 at the Maryland Department of Health and Mental Hygiene using a real-time reverse transcription polymerase chain reaction assay. We used Fisher's exact test to compare proportions, Student's t-test or Wilcoxon rank-sum test to compare continuous variables, and logistic regression to evaluate associations. Results: We identified 99 patients with SCD and influenza (64 seasonal influenza A, 25 seasonal influenza B, and 10 pandemic influenza A) during the study period (Figure). Eighteen patients had pandemic (10) or seasonal (8) influenza during the 2008 – 2009 season and July of 2009. Clinical symptoms, such as reported fever (90%), cough (93%), and rhinorrhea (79%), were similar. However, those with pandemic influenza were more likely to have acute chest syndrome and to require intensive care and ventilator support (Table). In a multivariable logistic regression model, older age (OR 1.2 per year, 95% CI 1.04 –1.3, P=.004) and pandemic influenza vs. seasonal influenza (OR 11, 95% CI 1.3 –88, P=0.025) were associated with increased risk of intensive care. Discussion: We found pandemic influenza to be associated with a greater risk of life-threatening complications than seasonal influenza in young patients with SCD, including an estimated 3-fold increased risk of acute chest syndrome and a 9-fold increased risk of need for intensive care. Older age may also be a risk factor for more severe disease, but could also reflect referral bias (with only the sickest adolescents and young adults being referred for tertiary pediatric care). We conclude that vaccination against pandemic influenza, in addition to seasonal influenza, will be essential for children and young adults with SCD and others in their households. The influenza season was defined as for 1995 (7/1/95–6/30/96) for each year. Disclosures: Casella: Boehringer Ingelheim: Consultancy, Honoraria; Cytrex: Research Funding; Ikaria: Research Funding.

Epidemiological analysis of critically ill adult patients with pandemic influenza A(H1N1) in South Korea

2012 ◽  
Vol 141 (5) ◽  
pp. 1070-1079 ◽  
Author(s):  
S. B. HONG ◽  
E. Y. CHOI ◽  
S. H. KIM ◽  
G. Y. SUH ◽  
M. S. PARK ◽  
...  
Keyword(s):  
South Korea ◽  
Influenza A ◽  
Multivariate Logistic Regression Analysis ◽  
H1n1 Influenza ◽  
Epidemiological Analysis ◽  
Influenza A H1n1 ◽  
Failure Assessment ◽  
2009 H1n1 ◽  
Independent Risk Factors ◽  
Chronic Comorbidities

SUMMARYA total of 245 patients with confirmed 2009 H1N1 influenza were admitted to the intensive-care units of 28 hospitals (South Korea). Their mean age was 55·3 years with 68·6% aged >50 years, and 54·7% male. Nine were obese and three were pregnant. One or more comorbidities were present in 83·7%, and nosocomial acquisition occurred in 14·3%. In total, 107 (43·7%) patients received corticosteroids and 66·1% required mechanical ventilation. Eighty (32·7%) patients died within 30 days after onset of symptoms and 99 (40·4%) within 90 days. Multivariate logistic regression analysis showed that the clinician's decision to prescribe corticosteroids, older age, Sequential Organ Failure Assessment score and nosocomial bacterial pneumonia were independent risk factors for 90-day mortality. In contrast with Western countries, critical illness in Korea in relation to 2009 H1N1 was most common in older patients with chronic comorbidities; nosocomial acquisition occurred occasionally but disease in obese or pregnant patients was uncommon.

scholarly journals Hospitalized Children with 2009 Pandemic Influenza A (H1N1): Comparison to Seasonal Influenza and Risk Factors for Admission to the ICU

PLoS ONE ◽  
2010 ◽  
Vol 5 (12) ◽  
pp. e15173 ◽  
Author(s):  
Dayanand Bagdure ◽  
Donna J. Curtis ◽  
Emily Dobyns ◽  
Mary P. Glodé ◽  
Samuel R. Dominguez
Keyword(s):  
Risk Factors ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Hospitalized Children ◽  
Influenza A H1n1

scholarly journals Response to 2009 Pandemic Influenza A (H1N1) Vaccine in HIV-Infected Patients and the Influence of Prior Seasonal Influenza Vaccination

PLoS ONE ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. e16496 ◽  
Author(s):  
Darius Soonawala ◽  
Guus F. Rimmelzwaan ◽  
Luc B. S. Gelinck ◽  
Leo G. Visser ◽  
Frank P. Kroon
Keyword(s):  
Influenza Vaccination ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Seasonal Influenza ◽  
H1n1 Vaccine ◽  
Seasonal Influenza Vaccination ◽  
Influenza A H1n1

Pandemic 2009 Influenza A (H1N1) Virus among Japanese Healthcare Workers: Seroprevalence and Risk Factors

2012 ◽  
Vol 33 (1) ◽  
pp. 58-62 ◽  
Author(s):  
Yoko Nukui ◽  
Shuji Hatakeyama ◽  
Takatoshi Kitazawa ◽  
Tamami Mahira ◽  
Yoshizumi Shintani ◽  
...  
Keyword(s):  
Risk Factors ◽  
Healthcare Workers ◽  
Influenza A ◽  
H1n1 Virus ◽  
Healthcare Personnel ◽  
Care Hospital ◽  
Occupational Risk Factors ◽  
Increased Risk ◽  
Influenza A H1n1 ◽  
2009 H1n1

Objective.To evaluate the seroprevalence and risk factors for 2009 influenza A (H1N1) virus infection among healthcare personnel.Design.Observational cross-sectional study.Patients and Setting.Healthcare workers (HCWs) in an acute care hospital.Methods.Between September 14 and October 4, 2009, before 2009 H1N1 vaccination, we collected serological samples from 461 healthy HCWs. Hemagglutination-inhibition antibody assays were conducted. To evaluate the risk factors of seropositivity for 2009 H1N1 virus, gender, age, profession, work department, usage of personal protective equipment, and seasonal influenza vaccination status data were gathered via questionnaires.Results.Our survey showed that doctors and nurses were at highest risk of seropositivity for the 2009 H1N1 virus (odds ratio [OR], 5.25 [95% confidence interval {CI}, 1.21–22.7]). An increased risk of seropositivity was observed among pediatric, emergency room, and internal medicine staff (adjusted OR, 1.98 [95% CI, 1.07–3.65]). Risk was also higher among HCWs who had high titers of antibodies against the seasonal H1N1 virus (adjusted OR, 1.59 [95% CI, 1.02–2.48]).Conclusions.Seropositivity for the 2009 H1N1 virus was associated with occupational risk factors among HCWs.Infect Control Hosp Epidemiol 2012;33(1):58-62

scholarly journals Situational Awareness and Health Protective Responses to Pandemic Influenza A (H1N1) in Hong Kong: A Cross-Sectional Study

PLoS ONE ◽  
2010 ◽  
Vol 5 (10) ◽  
pp. e13350 ◽  
Author(s):  
Qiuyan Liao ◽  
Benjamin Cowling ◽  
Wing Tak Lam ◽  
Man Wai Ng ◽  
Richard Fielding
Keyword(s):  
Hong Kong ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Situational Awareness ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Influenza A H1n1

Excess mortality associated with the 2009 pandemic of influenza A(H1N1) in Hong Kong

2011 ◽  
Vol 140 (9) ◽  
pp. 1542-1550 ◽  
Author(s):  
L. YANG ◽  
K. P. CHAN ◽  
B. J. COWLING ◽  
S. S. CHIU ◽  
K. H. CHAN ◽  
...  
Keyword(s):  
Hong Kong ◽  
Influenza A ◽  
Excess Mortality ◽  
Seasonal Influenza ◽  
Mortality Rates ◽  
Timely Manner ◽  
Mortality Burden ◽  
Influenza A H1n1 ◽  
Excess Deaths ◽  
Modelling Approach

SUMMARYReliable estimates of the burden of 2009 pandemic influenza A(pH1N1) cannot be easily obtained because only a small fraction of infections were confirmed by laboratory tests in a timely manner. In this study we developed a Poisson prediction modelling approach to estimate the excess mortality associated with pH1N1 in 2009 and seasonal influenza in 1998–2008 in the subtropical city Hong Kong. The results suggested that there were 127 all-cause excess deaths associated with pH1N1, including 115 with cardiovascular and respiratory disease, and 22 with pneumonia and influenza. The excess mortality rates associated with pH1N1 were highest in the population aged ⩾65 years. The mortality burden of influenza during the whole of 2009 was comparable to those in the preceding ten inter-pandemic years. The estimates of excess deaths were more than twofold higher than the reported fatal cases with laboratory-confirmed pH1N1 infection.

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