Robert Allard

Severity and Prognosis of Acute Human Immunodeficiency Virus Type 1 Illness: A Dose-Response Relationship

This study examined the relationship between the severity of acute human immunodeficiency virus type 1 (HIV-1) illness and disease progression and death. The population included 218 patients with acute HIV-1 illness and 41 asymptomatic patients who underwent HIV-1 seroconversion; the patients were followed up prospectively. We analyzed progression to Centers for Disease Control and Prevention clinical categories B and C (AIDS-defining conditions) and death according to an additive clinical score (CS) based on six predictive clinical features at the time of acute HIV-1 infection. Compared with patients with a CS of 0 (asymptomatic patients), those with a CS of 3-4 and 5-6 had faster progression to category B disease (adjusted hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.01-1.92; and HR, 1.80; 95% CI, 1.34-2.40; respectively); those with a CS of 5-6 had faster progression to category C disease (HR, 1.37; 95% CI, 1.01-1.89) and death (HR, 2.05; 95% CI, 1.27-3.32). Thus, the number of symptoms and signs at the time of acute HIV-1 illness affects disease progression and survival, even in symptomatic patients who have undergone seroconversion.

Pre-exposure rabies prophylaxis for the international traveller: a decision analysis.

To determine for which travellers pre-exposure rabies prophylaxis is indicated, a decision tree-based model has been developed which enables the comparison of one million travellers going to rabies-endemic areas who receive a pre-exposure rabies prophylaxis to one million travellers also going to rabies-endemic areas who are not vaccinated. Using data obtained from a review of the literature, probabilities were assigned to each significant outcome. When numbers were not available, estimates were used and tested with a sensitivity analysis. Routine pre-exposure prophylaxis would prevent 0.054 cases per million adult travellers per month at a cost of 5 billion (thousand million) Canadian dollars. In the worst-case scenario, which concerns children, the cost per case prevented per year of stay would be

Invasive Group A Streptococcal Infections, Clinical Manifestations and Their Predictors, Montreal, 1995–2002

275,000 dollars. Our decision analysis leads us to believe that routine pre-exposure prophylaxis given to travellers heading for rabies-endemic regions of the world is not indicated. We conclude that pre-exposure rabies prophylaxis is a medical decision that must be individualized for every traveller and should be particularly considered for children at high risk of being exposed to rabies, who are leaving for a long stay (more than one year) and who will not have rapid access to medical services and rabies immunobiologics.

Association between the Rate of CD4+ T Cell Decrease and the Year of Human Immunodeficiency Virus (HIV) Type 1 Seroconversion among Persons Enrolled in the Swiss HIV Cohort Study

Specific clinical manifestations of invasive group A streptococcal infection appear to develop not in response to the pathogen, but rather to host or environmental factors.

Estimating Attributable Mortality Due to Nosocomial Infections Acquired in Intensive Care Units

The aim of this study was to investigate the early CD4+ T cell response among human immunodeficiency virus type 1 (HIV-1) seroconverters in relation to their year of seroconversion. Study participants were enrolled in the Swiss HIV Cohort Study between 1985 and 1995 and had not received antiretroviral treatment. The slope of the CD4+ T cell count within 2 years after seroconversion was significantly associated with the year of seroconversion, by sex and by use of injection drugs, when controlling for initial CD4+ cell count. These results show that the loss of CD4+ cells might be associated with the year of seroconversion, suggesting a change in the pathogenesis of HIV across the years. If these results are confirmed, they could have important implications for the pathogenesis of and therapeutic strategies for HIV-1 infection.

Surveillance of invasive Streptococcus pneumoniae infection in the province of Quebec, Canada, from 1996 to 1998: serotype distribution, Antimicrobial susceptibility, and clinical characteristics.

BACKGROUNDnThe strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken.nnnOBJECTIVEnTo assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients.nnnSETTINGnEleven ICUs of a French university hospital.nnnDESIGNnWe analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis.nnnRESULTSnAmong 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection.nnnCONCLUSIONSnICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

Campylobacter coli Outbreak in Men Who Have Sex with Men, Quebec, Canada, 2010–2011

ABSTRACT In the province of Quebec, Canada, from 1996 to 1998, 3,650 invasive Streptococcus pneumoniae infections were reported. A total of 1,354 isolates were serotyped and tested for antimicrobial susceptibility. The distribution of serotypes remained stable over the 3 years, with serotypes 14, 6B, 4, 9V, 23F, and 19F accounting for 61% of the isolates. Overall, 90% of isolates were included in the current 23-valent vaccine and 67% were included in the 7-valent conjugate vaccine. We were able to determine that resistance to penicillin and to other antibiotics is increasing.

Prognostic value of the CD4+ T cell count for HIV-1 infected patients with advanced immunosuppression

During September 2010–November 2011, a cluster of erythromycin-susceptible, tetracycline- and ciprofloxacin-resistant Campylobacter coli pulsovar 1 infections was documented, involving 10 case-patients, in Montreal, Quebec, Canada. The findings suggested sexual transmission of an enteric infection among men who have sex with men.

Community-Acquired Clostridium difficile-Associated Diarrhea, Montreal, 2005-2006: Frequency Estimates and Their Validity

The prognostic value of the CD4+ T cell count is not clearly established for HIV-1 infected patients with an advanced immunosuppression. The aim of this study was to assess the relationship between CD4+ T cell counts and survival in patients with less than 50 CD4+ T cells per mm3 (/mm3). We examined an historical cohort of 97 patients with 2 consecutive CD4+ T cells determinations < 50/mm3 within 3 months, followed at a university hospital of the University of Montreal. The proportion of men was 93% with 74% being homo/bisexual. The means of the 2 CD4+ T cell counts/mm3 were 25 and 25.1 respectively. Median survival after the first CD4+ T cell count < 50 CD4+ T cells/mm3 was 15.2 months. Using the proportional hazard model, the median survival of patients with 2 consecutive CD4+ T cell counts < or = 20/mm3 was 9.3 months compared to 19.2 for those with 20-50 CD4+ T cells/mm3 (P < 0.0001). It seems then, that the CD4+ T cell count is a helpful prognostic marker, even in very immunosuppressed patients. Its prognostic value is more accurate if the measurement is replaced within 1-3 months because of high variability at this level of immunosuppression.

The incubation period of acute retroviral syndrome as a multistep process: A parametric survival analysis

A retrospective search for community-acquired Clostridium difficile-associated diarrhea in 15 hospitals revealed important discrepancies with numbers for the same period reported in real time to the surveillance system. Several of the observed problems could be solved by implementing case-by-case notification with subsequent investigation by local public health, as for other reportable diseases.