Seasonal influenza-associated intensive care unit admission and death in tropical Singapore, 2011-2015.

BACKGROUND: Seasonal influenza can cause severe illness leading to intensive care unit (ICU) admission and death. OBJECTIVE: To define the clinical and epidemiological features of severe seasonal influenza infection and factors associated with mortality. STUDY DESIGN: A retrospective review was conducted on all patients with laboratory-confirmed influenza infection who were either admitted into the ICU or died in the two largest tertiary hospitals in Singapore from 2011-2015. RESULTS: Of 520 patients included in our study, 423 (81.3%) had influenza A infection and the rest with influenza B. Of patients with influenza A infection, 70.0% (296/423) were subtyped, of whom 24.0% (71/296) had A/H1N1pdm2009 and 76.0% (225/296) had A/H3N2. The median age of patients was 72 years (IQR 61-82). Males constituted 53.1% (276/520). Median Charlson comorbidity index score was 1 (IQR 0-3). About 70% had physical or radiological evidence of pneumonia upon admission. In-hospital mortality was 58.1% (302/520). On multiple logistic regression analysis, factors positively associated with mortality were age ≥65 years (adjusted odds ratio, aOR = 3.64, 95%CI 2.21-5.99, p < 0.001), malignancy (aOR = 2.53, 95%CI 1.12-5.73; p = 0.026), and hypoalbuminemia (aOR = 2.16, 95%CI 1.26-3.73; p = 0.005), while antiviral therapy (aOR = 0.33, 95%CI 0.17-0.63; p < 0.001) and ventilation (aOR = 0.23, 95% CI 0.13-0.39; p < 0.001) were negatively associated. CONCLUSIONS: Patients with severe seasonal influenza infection were characterized by advanced age, hypoalbuminemia and presence of pneumonia on admission. Age ≥65 years, malignancy, and hypoalbuminemia were associated with increased mortality, and antiviral therapy and ventilation with decreased mortality.

Diagnostic Accuracy of Parameters for Zika and Dengue Virus Infections, Singapore.

Singapore experienced its first documented Zika virus outbreak in 2016. We identified clinical and laboratory parameters that increase the probability for Zika or dengue virus infection. Early during the illness, combinations of key parameters obtained through clinical assessment and hematologic tests can help distinguish between these infections.

Group B Streptococcus Sequence Type 283 Disease Linked to Consumption of Raw Fish, Singapore.

An outbreak of invasive group B Streptococcus (GBS) disease occurred in Singapore in mid-2015. We conducted a case-control study of 22 adults with invasive GBS infections during June 21-November 21, 2015. Consumption of raw fish was strongly associated with invasive sequence type 283 infections, but not with non-sequence type 283 infections.

Rates and predictors for influenza vaccine prescriptions among HIV-infected clinic patients in Singapore

<p><b>INTRODUCTION</b>Although Singapore national guidelines recommend influenza vaccination for individuals with comorbidities, the vaccine uptake remains relatively low. This study examines the rates of influenza vaccine prescriptions in a clinic population, and patient, doctor and clinic factors that could affect the vaccine prescribing rates.</p><p><b>MATERIALS AND METHODS</b>This retrospective review utilised electronic medical records from HIV-infected patients seen in an infectious disease (ID) specialist clinic. Data from 40 randomly selected patients per physician were analysed for the outcome of influenza vaccine prescriptions from 1 January to 31 December 2007. All 7 consultants and the 6 ID registrars who had spent at least 4 months in the Department during 2007 were included. Data analysed included patient, physician, and clinic characteristics, and clinically relevant outcomes of admission within a year, and the length of hospital stay.</p><p><b>RESULTS</b>Of the 461 HIV-infected patients analysed for this study, only 107 (23%) were prescribed influenza vaccine in 2007. Vaccine prescribing rates by individual physicians ranged from 0% to 77%. The outcome of vaccine prescribing was analysed by patient demographics (age >40 years, gender, race), physician characteristics (doctor grade, gender and training), and clinic volumes (number of patients per clinic session). Multivariate analysis demonstrated that patients with female doctors (OR 1.8, 95% CI, 1.1 to 3.0, P = 0.017), and doctors with overseas medical training (OR 11.6, 95% CI, 6.0 to 22.2, P <0.001) were significantly more likely to have influenza vaccine prescribed. On univariate analysis, patients were more likely to be admitted if they were male (OR 2.1, 95% CI, 1.0 to 5.1, P = 0.041), and over 40 years old (OR 2.1, 95% CI, 1.1 to 4.5, P = 0.024). Patients prescribed influenza vaccine showed a non-significant trend for protection against admission (OR 0.7, P = 0.288), and shorter length of stay (median 5 vs 9 days, P = 0.344).</p><p><b>CONCLUSION</b>Influenza vaccine prescribing for HIV-infected outpatients in 2007 was only 23%, even in an ID specialist clinic. There was substantial variability in prescribing rates by individual physicians. Neither patient demographics nor patient volumes per clinic session had an impact on the prescribing rates, but significant predictors included physician gender and medical school training. Patients prescribed influenza vaccine had fewer admissions and shorter hospital lengths of stay, although these trends were non-significant.</p>

Causes of death and factors associated with early death among human immunodeficiency virus (HIV)-infected persons in Singapore: pre-highly active antiretroviral therapy (HAART) and Peri-HAART

<p><b>INTRODUCTION</b>Highly active antiretroviral therapy (HAART) has greatly changed the epidemiology of human immunodefi ciency virus (HIV) mortality. The aim of this study is to compare the causes of death and factors associated with early death in HIV-infected persons in the pre- and peri-highly active antiretroviral therapy (HAART) periods.</p><p><b>MATERIALS AND METHODS</b>We conducted a retrospective review of 483 HIV-infected persons who were diagnosed with HIV from 1985 to 2000, and had died within 5 years of the diagnosis. We examined the temporal change in the primary causes of death between those who were diagnosed in the pre-HAART (1985 to 1995) and peri-HAART (1996 to 2000) periods, and compared the demographic and clinical characteristics of the 2 groups.</p><p><b>RESULTS</b>During the peri-HAART period, HIV encephalopathy, cryptococcal meningitis, and lymphoma were no longer the leading causes of death. Opportunistic infections remained important causes of death. Early deaths from the peri-HAART period were older (60 years and above) at diagnosis (Adj OR 7.50; 95% CI, 1.78 to 31.58), more likely to be divorced (Adj OR 5.05, 95% CI, 1.96 to 13.02) and tended to have a low baseline CD4 cell count of <50 cells/ uL (Adj OR 2.18, 95% CI, 1.14 to 4.16) , and were more likely to have received HAART (Adj OR 5.19; 95% CI, 2.22 to 12.12) than early deaths from the pre-HAART period.</p><p><b>CONCLUSION</b>In the peri-HAART era, HIV-infected persons who died within 5 years of diagnosis were those who were older (≥60 years), divorced, or who presented with very late-stage disease (CD4 <50) at diagnosis. More targeted public health interventions, such as targeted public health messages and outreach to increase access to HIV testing and treatment should be developed for these subpopulations.</p>

Influenza B outbreak among influenza-vaccinated welfare home residents in Singapore

<p><b>INTRODUCTION</b>Outbreaks of acute respiratory illness occur commonly in long-term care facilities (LTCF), due to the close proximity of residents. Most influenza outbreak reports have been from temperate countries. This study reports an outbreak of influenza B among a highly immunised resident population in a welfare home in tropical Singapore, and discusses vaccine efficacy and the role of acute respiratory illness surveillance for outbreak prevention and control.</p><p><b>MATERIALS AND METHODS</b>During the period from 16 to 21 March 2007, outbreak investigations and active case finding were carried out among residents and nursing staff at the welfare home. Interviews and medical notes review were conducted to obtain epidemiological and clinical data. Hospitalised patients were tested for respiratory pathogens. Further genetic studies were also carried out on positive respiratory samples.</p><p><b>RESULTS</b>The overall clinical attack rate was 9.4% (17/180) in residents and 6.7% (2/30) in staff. All infected residents and staff had received influenza immunisation. Fifteen residents were hospitalised, with 2 developing severe complications. Genetic sequencing revealed that the outbreak strain had an 8.2% amino acid difference from B/Malaysia/2506/2004, the 2006 southern hemisphere influenza vaccine strain, which the residents and staff had earlier received.</p><p><b>CONCLUSIONS</b>A mismatch between the vaccine and circulating influenza virus strains can result in an outbreak in a highly immunised LTCF resident population. Active surveillance for acute respiratory illness in LTCFs could be implemented for rapid detection of antigenic drift. Enhanced infection control and other preventive measures can then be deployed in a timely manner to mitigate the effect of any outbreaks.</p>