Monique Douville-Fradet

Pneumonia after implementation of the pneumococcal conjugate vaccine program in the province of Quebec, Canada.

Background: In Canada, a pneumococcal conjugate vaccine was licensed in 2001, and in the province of Quebec, a publicly-funded program was implemented for high-risk children in 2002, using a 4-dose schedule, and for all children in 2004, using a 3-dose schedule. Objectives: To describe the epidemiology of hospitalized pneumonia in the population aged <5 years. Methodology: Hospital discharge records with a main diagnosis of pneumonia, pleurisy, or empyema were analyzed regarding monthly frequencies by diagnostic categories, duration of stay, proportion of cases admitted to the intensive care unit, and case fatality. Results: Lobar pneumonia represented 32% of 25,319 all-cause pneumonia admissions during the period April 1997 to March 2006. Beginning in the spring of 2004, there was a marked decrease in the frequency of lobar pneumonia, whereas unspecified pneumonia tended to increase to a lesser extent. Compared with the pre-pneumococcal conjugate vaccine period, admissions for all-causes pneumonia decreased by 13% after program implementation and there was no increase in empyema cases. Conclusions: Results are reassuring as to the effectiveness of the pneumococcal vaccination program in Quebec.

Risk factors for hospitalization and severe outcomes of 2009 pandemic H1N1 influenza in Quebec, Canada.

Please cite this paper as: Gilca et al. (2011) Risk Factors for Hospitalization and Severe Outcomes of 2009 Pandemic H1N1 Influenza in Quebec, Canada. Influenza and Other Respiratory Viruses 5(4), 247–255

Impact of 2+1 pneumococcal conjugate vaccine program in the province of Quebec, Canada.

BACKGROUND Quebec was the first jurisdiction in the world to recommend a 3-dose (2+1) pneumococcal conjugate vaccine (PCV) schedule. The program was implemented in December 2004 with a catch-up for children <5 years. PCV-7 was first used and replaced, respectively, by PCV-10 in 2009 and by PCV-13 in 2011. METHODS Cases of invasive pneumococcal disease (IPD) notified to public health authorities and isolates submitted to the provincial reference laboratory during the period 2000-2011 were analyzed. RESULTS IPD incidence in children <5 years was 67/100,000 in 2001-2004, and decreased to 32/100,000 in 2007-2009 following PCV-7 implementation (p<0.01). A further decrease to 24/100,000 was observed in 2010-2011 following PCV-10 introduction (p<0.01). PCV-7 serotypes represented 82% of the total IPD cases in 2000-2004 and elimination was achieved in 2011. Main emerging serotypes were 19A and 7F. Children exposed to the PCV-10 experienced lower IPD rates and all serotypes contributed to the decline, mainly 7F and 19A. In adults, a decrease of low magnitude was observed in 2005-2006 but rates in 2007-2009 were higher than in the prevaccination period. CONCLUSIONS A 3-dose PCV schedule with high uptake is highly effective and should be recommended worldwide. Serotype replacement eroded benefits especially in adults. PCV-10 introduction had an effect and the impact of PCV-13 use remains to be evaluated.

Field Performance of a Rapid Diagnostic Test for Influenza in an Ambulatory Setting

ABSTRACT Provided test characteristics are adequate, point-of-care rapid antigen detection tests for influenza could improve the timeliness and appropriateness of clinical decisions. Our objective was to estimate the field sensitivity and specificity of the Quidel QuickVue Influenza A+B test in an ambulatory setting. The sensitivity and specificity of the Quidel QuickVue test was evaluated against reverse-transcriptase PCR (RT-PCR) on nasopharyngeal specimens collected over two consecutive influenza seasons from ambulatory patients consulting for influenza-like illness (ILI) within 7 days of ILI onset. A total of 491 patients with ILI (180 in 2006 to 2007 and 311 in 2007 to 2008) provided specimens that were tested both by PCR and by the Quidel QuickVue test. Among the 267 patients positive by PCR (55%), 52 were also positive by the QuickVue test, for an overall sensitivity of 19.5% (95% confidence interval [95% CI], 14.7% to 24.2%). Among the 221 PCR-negative patients, 2 were positive for influenza B virus by the rapid test (<1%), for an overall specificity of 99.1% (95% CI, 97.9 to 100%). The field sensitivity of the test varied little with the age or gender of the patient, immunization status, delay since the onset of symptoms, or influenza season. The sensitivity of the test was slightly but nonsignificantly higher for influenza B virus (23%) than for influenza A virus (18%). Despite its high specificity, the low sensitivity of the Quidel QuickVue Influenza A+B test is too poor to direct clinical decisions for ambulatory patients with ILI. Negative results cannot rule out the diagnosis of influenza, and in that context, this test is of questionable utility for routine application in the clinical setting.

The Changing Epidemiology of Meningococcal Disease in Quebec, Canada, 1991–2011: Potential Implications of Emergence of New Strains

Background In order to inform meningococcal disease prevention strategies, we analysed the epidemiology of invasive meningococcal disease (IMD) in the province of Quebec, Canada, 10 years before and 10 years after the introduction of serogroup C conjugate vaccination. Methodology IMD cases reported to the provincial notifiable disease registry in 1991–2011 and isolates submitted for laboratory surveillance in 1997–2011 were analysed. Serogrouping, PCR testing and assignment of isolates to sequence types (ST) by using multilocus sequence typing (MLST) were performed. Results Yearly overall IMD incidence rates ranged from 2.2–2.3/100,000 in 1991–1992 to 0.49/100,000 in 1999–2000, increasing to 1.04/100,000 in 2011. Among the 945 IMD cases identified by laboratory surveillance in 1997–2011, 68%, 20%, 8%, and 3% were due to serogroups B, C, Y, and W135, respectively. Serogroup C IMD almost disappeared following the implementation of universal childhood immunization with monovalent C conjugate vaccines in 2002. Serogroup B has been responsible for 88% of all IMD cases and 61% of all IMD deaths over the last 3 years. The number and proportion of ST-269 clonal complex has been steadily increasing among the identified clonal complexes of serogroup B IMD since its first identification in 2003, representing 65% of serogroup B IMD in 2011. This clonal complex was first introduced in adolescent and young adults, then spread to other age groups. Conclusion Important changes in the epidemiology of IMD have been observed in Quebec during the last two decades. Serogroup C has been virtually eliminated. In recent years, most cases have been caused by the serogroup B ST-269 clonal complex. Although overall burden of IMD is low, the use of a vaccine with potential broad-spectrum coverage could further reduce the burden of disease. Acceptability, feasibility and cost-effectiveness studies coupled with ongoing clinical and molecular surveillance are necessary in guiding public policy decisions.

Mid-Season Estimates of Influenza Vaccine Effectiveness against Influenza A(H3N2) Hospitalization in the Elderly in Quebec, Canada, January 2015.

Background The 2014/15 influenza season in Canada was characterized by an early epidemic due to vaccine-mismatched influenza A(H3N2) viruses, disproportionately affecting elderly individuals ≥65-years-old. We assessed vaccine effectiveness (VE) against A(H3N2) hospitalization among elderly individuals during the peak weeks of the 2014/15 epidemic in Quebec, Canada. Methods Nasal specimens and clinical/epidemiological data were collected within 7 days of illness onset from elderly patients admitted with respiratory symptoms to one of four participating hospitals between November 30, 2014 and January 13, 2015. Cases tested RT-PCR positive for influenza A(H3N2) and controls tested negative for any influenza. VE was assessed by test-negative case-control design. Results There were 314 participants including 186 cases (62% vaccinated) and 128 controls (59% vaccinated) included in primary VE analysis. Median age was 81.5 years, two-thirds were admitted from the community and 91% had underlying comorbidity. Crude VE against A(H3N2) hospitalization was -17% (95%CI: -86% to 26%), decreasing to -23% (95%CI: -99 to 23%) with adjustment for age and comorbidity, and to -39% (95%CI: -142 to 20%) with additional adjustment for specimen collection interval, calendar time, type of residence and hospital. In sensitivity analyses, VE estimates were improved toward the null with restriction to participants admitted from the community (-2%; 95%CI: -105 to 49%) or with specimen collection ≤4 days since illness onset (- 8%; 95%CI: -104 to 43%) but further from the null with restriction to participants with comorbidity (-51%; 95%CI: -169 to 15%). Conclusion The 2014/15 mismatched influenza vaccine provided elderly patients with no cross-protection against hospitalization with the A(H3N2) epidemic strain, reinforcing the need for adjunct protective measures among high-risk individuals and improved vaccine options.

Other Respiratory Viruses Are Important Contributors to Adult Respiratory Hospitalizations and Mortality Even During Peak Weeks of the Influenza Season

This prospective study conducted during 2 influenza seasons shows that even during the peak weeks of influenza circulation, other respiratory viruses contribute substantially to adult respiratory hospitalizations and mortality and, among the elderly, may exceed influenza.

Hospitalizations for Diarrhea in Quebec Children from 1985 to 1998: Estimates of Rotavirus-Associated Diarrhea

OBJECTIVE To characterize the incidence and duration of hospitalization due to diarrhea and to assess the proportion of hospitalizations that are attributed to rotavirus-associated diarrhea. DESIGN Retrospective study of hospitalization data. SETTING Hospitals located in Quebec. POPULATION STUDIED Children from one to 59 months of age who were discharged from hospital from April 1, 1985 to March 31, 1998. MAIN RESULTS There were 63,827 hospitalizations for diarrhea over the study period, for an average of 4910 hospitalizations/year. The epidemic curve showed a periodicity with regular alternation of high and low annual peaks. The number of hospitalizations for rotavirus-associated diarrhea was estimated according to three different methods. The estimates varied between 1353 and 1849 hospitalizations due to rotavirus-associated diarrhea/year over the 13-year period, with good agreement between the results of the three methods for a one-month to five years of age incidence of 320 hospitalizations for rotavirus-associated diarrhea/100,000 children. The average duration of hospital stay decreased from 5.2 days in 1985 to 3.3 days in 1998. CONCLUSIONS The present article shows the importance of diarrhea hospitalizations among children and the alternating peak-year periodicity.

Burden of Chickenpox on Families: A Study in Quebec

OBJECTIVE To estimate the nonhospital costs of treating chickenpox and to ascertain the opinion of parents regarding the usefulness of vaccination. DESIGN Retrospective postal survey. SETTING Province of Quebec. PARTICIPANTS Random sample of 3333 families with children aged six months to 12 years. OUTCOME MEASURES For cases of chickenpox that occurred between September 1, 1997 and August 31, 1998, the use of health services, time away from school or work, patient care required, direct and indirect costs for the families and the health care system, and the opinion of parents regarding chickenpox and the vaccine were evaluated. RESULTS The response rate was 64.7%, and 18.8% of households reported a history of chickenpox, a total of 693 cases. A physician was consulted in 45.8% of these cases, and medication was used in 91.7%. The frequency of hospitalizations was 0.6%. Time away from work or school caused by the disease was 4.1 days on average, with 46.5% of absences being attributed to the risk of contagion. The total average cost of a case of chickenpox was

Evaluation of the New World Health Organization Case Definition of Severe Acute Respiratory Infection for Influenza Surveillance During the Peak Weeks of Two Influenza Seasons in Quebec, Canada

225. Direct expenses for households accounted for 11% of the total cost, public sector direct costs 7%, indirect costs related to absence from work 38% and caregiving time 45%. A majority of parents (70%) were in favour of a systematic childhood immunization program. CONCLUSIONS Chickenpox without complications is disruptive for families, but the direct costs for families and the public sector are relatively small.