Upsurge of chlamydial reinfection in a large Canadian city: an indication of suboptimal chlamydia screening practices?

OBJECTIVES: Given the limited knowledge on chlamydial reinfection (CR) in Canada, we examined the extent and predictors of CR in Montréal, a large Canadian city. METHODS: We retrospectively studied all Montréal residents aged > or =10 years for whom > or =1 laboratory-confirmed chlamydial infection was reported to the public health department between 1988 and 2007 (n = 44,580). Each person was passively followed for two years after baseline infection or until reinfection. Socio-demographic factors and histories of other notifiable diseases were examined as potential predictors. Cox multivariate regression was used to model the time to CR. Survival analyses were stratified by age group (<25 vs. > or =25 years). RESULTS: We estimated an overall two-year CR rate of 6.4%, an incidence density of 3.5 per 100 person-years, and a median time to reinfection of nine months. CR significantly increased over time. Among persons <25 years, reinfection was significantly more likely among females [adjusted hazard ratio (AHR): 1.58] and younger participants (10-14 years: AHR: 2.98; 15-19 years: AHR: 1.81). Residing within the South Central sector was deleterious for six months following initial infection after which it became protective. Among persons > or =25 years, a history of sexually transmitted infections increased the risk of reinfection (AHR: 1.79). CONCLUSION: CR is a significant and growing problem in Montreal. The current recommendation for a single repeat screening six months posttreatment might be usefully complemented with additional screenings. Our results also underscore the importance of screening high-risk populations, particularly young women.

Strategies Used by Older Patients to Prevent Functional Decline During Hospitalization.

Almost one third of older patients hospitalized for acute care suffer functional decline. Few studies have investigated the point of view of older patients on prevention of this decline. Within the framework of a descriptive qualitative study, the perceptions of 30 hospitalized older adults were collected regarding their personal prevention strategies, the barriers to implementing these, and nursing staff interventions deemed useful. Results show that participants are sensitive to the risk of functional decline and utilize various preventive strategies particularly to maintain their physical abilities, maintain good spirits, keep a clear mind, and foster nutrition and sleep. Their strategies are difficult to implement on account of internal and external barriers. Nursing interventions deemed useful are good relational approach, strong basic care, appropriate assessment, and respect for level of autonomy. The study underscores that older hospitalized patients are applying strategies to prevent functional decline, but some nursing interventions may thwart their efforts.

Enteric disease episodes and the risk of acquiring a future sexually transmitted infection: a prediction model in Montreal residents.

OBJECTIVE: The sexual transmission of enteric diseases poses an important public health challenge. We aimed to build a prediction model capable of identifying individuals with a reported enteric disease who could be at risk of acquiring future sexually transmitted infections (STIs). MATERIALS AND METHODS: Passive surveillance data on Montreal residents with at least 1 enteric disease report was used to construct the prediction model. Cases were defined as all subjects with at least 1 STI report following their initial enteric disease episode. A final logistic regression prediction model was chosen using forward stepwise selection. RESULTS: The prediction model with the greatest validity included age, sex, residential location, number of STI episodes experienced prior to the first enteric disease episode, type of enteric disease acquired, and an interaction term between age and male sex. This model had an area under the curve of 0.77 and had acceptable calibration. DISCUSSION: A coordinated public health response to the sexual transmission of enteric diseases requires that a distinction be made between cases of enteric diseases transmitted through sexual activity from those transmitted through contaminated food or water. A prediction model can aid public health officials in identifying individuals who may have a higher risk of sexually acquiring a reportable disease. Once identified, these individuals could receive specialized intervention to prevent future infection. CONCLUSION: The information produced from a prediction model capable of identifying higher risk individuals can be used to guide efforts in investigating and controlling reported cases of enteric diseases and STIs.

Varicella vaccination for grades 4 and 5 students: from theory to practice.

BACKGROUND: In 2002-2003, as part of a pilot project, varicella vaccination was offered to susceptible students in grades 4 and 5 in schools whose health services are provided by a local community services centre in Montréal. This immunization campaign was merged with the hepatitis B immunization programme. OBJECTIVES: To calculate the proportion of grade 4 and 5 students susceptible to varicella; to calculate the proportion of susceptible students who agree to be vaccinated; to compare the proportion of susceptibles who agree to be vaccinated when varicella vaccination is offered with the first or the second dose of hepatitis B; and to assess whether a catch-up varicella immunization programme would affect the vaccine coverage of a concurrent hepatitis B vaccination programme. METHODS: The proportions of susceptible students and of parents of susceptibles who consented to vaccination were calculated. The proportions of parents of susceptibles who consented to vaccination were compared for both immunization strategies: varicella vaccination given with the first or second dose of hepatitis B vaccine. Logistic regression was performed to identify possible associations between consent to varicella vaccination and the various variables collected. Rates of vaccine coverage against hepatitis B after two doses were compared for the years 2000-2001 and 2002-2003. RESULTS: Of 3,856 registered students, 3,486 (90.4%) returned consent forms. Among the 3,272 students for whom information was available, 441 (13.5%) were susceptible, including 394 (89.3%) who consented to vaccination. The rates of vaccine coverage in the schools after two doses of hepatitis B vaccine were exactly the same for the 2000-2001 and 2002-2003 school years. CONCLUSION: Varicella vaccination of susceptible grade 4 and 5 students associated with a coincident hepatitis B vaccination campaign can be performed without negative impact on the hepatitis B vaccination programme.

Using age, triage score, and disposition data from emergency department electronic records to improve Influenza-like illness surveillance.

OBJECTIVE: Markers of illness severity are increasingly captured in emergency department (ED) electronic systems, but their value for surveillance is not known. We assessed the value of age, triage score, and disposition data from ED electronic records for predicting influenza-related hospitalizations. MATERIALS AND METHODS: From June 2006 to January 2011, weekly counts of pneumonia and influenza (P&I) hospitalizations from five Montreal hospitals were modeled using negative binomial regression. Over lead times of 0-5 weeks, we assessed the predictive ability of weekly counts of 1) total ED visits, 2) ED visits with influenza-like illness (ILI), and 3) ED visits with ILI stratified by age, triage score, or disposition. Models were adjusted for secular trends, seasonality, and autocorrelation. Model fit was assessed using Akaike information criterion, and predictive accuracy using the mean absolute scaled error (MASE). RESULTS: Predictive accuracy for P&I hospitalizations during non-pandemic years was improved when models included visits from patients ≥65 years old and visits resulting in admission/transfer/death (MASE of 0.64, 95% confidence interval (95% CI) 0.54-0.80) compared to overall ILI visits (0.89, 95% CI 0.69-1.10). During the H1N1 pandemic year, including visits from patients <18 years old, visits with high priority triage scores, or visits resulting in admission/transfer/death resulted in the best model fit. DISCUSSION: Age and disposition data improved model fit and moderately reduced the prediction error for P&I hospitalizations; triage score improved model fit only during the pandemic year. CONCLUSION: Incorporation of age and severity measures available in ED records can improve ILI surveillance algorithms.

Seroprevalence and risk factors for hepatitis A among Montreal street youth.

OBJECTIVE: To estimate the prevalence of hepatitis A virus (HAV) antibodies among Montreal street youth. METHOD: Anti-HAV antibody testing was performed on blood samples from a hepatitis B and C study conducted among street youth in 1995-96. RESULTS: Among the 427 youth aged 14 to 25 years, prevalence of HAV antibodies was 4.7% (95% confidence interval [CI]: 2.9%-7.2%). A multivariate logistic regression analysis showed that birth in a country with a high anti-HAV prevalence (Adjusted odds ratio [AOR]: 200.7; 95% CI: 38.1-1058.4), having had sexual partner(s) with history of unspecified hepatitis (AOR: 13.8; 95% CI: 4.2-45.2), and insertive anal penetration (AOR: 5.1; 95% CI: 1.6-16.7) were independently associated with infection. CONCLUSION: Based on the relatively low HAV prevalence, the high prevalence of risk factors for infection, and the substantial hepatitis B and C prevalence, vaccination against hepatitis A is now actively promoted among Montreal street youth.

Residential address errors in public health surveillance data: a description and analysis of the impact on geocoding.

The residential addresses of persons with reportable communicable diseases are used increasingly for spatial monitoring and cluster detection, and public health may direct interventions based upon the results of routine spatial surveillance. There has been little assessment, however, of the quality of address data in reportable disease notifications and of the corresponding impact of these errors on geocoding and routine public health practices. The objectives of this study were to examine address errors for a selected reportable disease in a large urban center in Canada and to assess the impact of identified errors on geocoding and the estimated spatial distribution of the disease. We extracted data for all notifications of campylobacteriosis from the Montreal public health department from 1995 to 2008 and used an address verification algorithm to determine the validity of the residential address for each case and to suggest corrections for invalid addresses. We assessed the types of address errors as well as the resulting positional errors, calculating the distance between the original address and the correct address as well as changes in disease density. Address errors and missing addresses were prevalent in the public health records (10% and 5%, respectively) and they influenced the observed distribution of campylobacteriosis in Montreal, with address correction changing case location by a median of 1.1 km. Further examination of the extent of address errors in public health data is essential, as is the investigation of how these errors impact routine public health functions.

Hospitalisations for gastroenteritis: the role of rotavirus.

To determine the proportion of hospitalisations for gastroenteritis caused by rotavirus, we tested for rotavirus stool samples of all children under the age of five hospitalised for gastroenteritis between 1 December 1999 and 30 May 2000 in seven community and specialised hospitals in Quebec. Of 944 children hospitalised, 565 (59.9%) were screened for rotavirus and 405 (71.7%) tested positive. From December to April, the proportion of positive results rose from 51.6 to 78.1%. Compared with children whose test results were negative, children who tested positive presented vomiting more frequently upon admission (88.9 versus 60.4%) and needed IV fluids in greater proportion (94.1 versus 78.0%), but spent less time in hospital (2.8 versus 3.3 days). Aside from dehydration, no complications were noted. In Quebec, a large majority of winter and spring hospitalisations for gastroenteritis in children is attributable to rotavirus.