Influenza Vaccine Does Not Increase the Risk of Coronavirus or Other Noninfluenza Respiratory Viruses: Retrospective Analysis From Canada, 2010-2011 to 2016-2017.

Influenza vaccine effectiveness against influenza and noninfluenza respiratory viruses (NIRVs) was assessed by test-negative design using historic datasets of the community-based Canadian Sentinel Practitioner Surveillance Network, spanning 2010-2011 to 2016-2017. Vaccine significantly reduced the risk of influenza illness by >40% with no effect on coronaviruses or other NIRV risk.

Influenza Vaccine Effectiveness by A(H3N2) Phylogenetic Subcluster and Prior Vaccination History: 2016-2017 and 2017-2018 Epidemics in Canada.

Background: The influenza A(H3N2) vaccine was updated from clade 3C.3a in 2015-2016 to 3C.2a for 2016-2017 and 2017-2018.

Getting a grippe on severity: a retrospective comparison of influenza-related hospitalizations and deaths captured in reportable disease and administrative data sources in Ontario, Canada.

Background: Since 2009, in Ontario, reportable disease surveillance data has been used for timely in-season estimates of influenza severity (i.e., hospitalizations and deaths).

Children under 10 years of age were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic in Canada: ‎possible cohort effect following the 2009 influenza pandemic.

IntroductionFindings from the community-based Canadian Sentinel Practitioner Surveillance Network (SPSN) suggest children were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic.AimTo compare the age distribution of A(H1N1)pdm09 cases in 2018/19 to prior seasonal influenza epidemics in Canada.MethodsThe age distribution of unvaccinated influenza A(H1N1)pdm09 cases and test-negative controls were compared across A(H1N1)pdm09-dominant epidemics in 2018/19, 2015/16 and 2013/14 and with the general population of SPSN provinces.

Effects of Absolute Humidity, Relative Humidity, Temperature, and Wind Speed on Influenza Activity in Toronto, Ontario, Canada.

The occurrence of influenza in different climates has been shown to be associated with multiple meteorological factors. The incidence of influenza has been reported to increase during rainy seasons in tropical climates and during the dry, cold months of winter in temperate climates. This study was designed to explore the role of absolute humidity (AH), relative humidity (RH), temperature, and wind speed (WS) on influenza activity in the Toronto, ON, Canada, area.

Should Sex Be Considered an Effect Modifier in the Evaluation of Influenza Vaccine Effectiveness?

We investigated sex as a potential modifier of influenza vaccine effectiveness (VE) between 2010-2011 and 2016-2017 in Canada. Overall VE was 49% (95% confidence interval [CI], 43% to 55%) for females and 38% (95% CI, 28% to 46%) for males (absolute difference [AD], 11%; = .03).

Early season co-circulation of influenza A(H3N2) and B(Yamagata): interim estimates of 2017/18 vaccine effectiveness, Canada, January 2018.

Using a test-negative design, we assessed interim vaccine effectiveness (VE) for the 2017/18 epidemic of co-circulating influenza A(H3N2) and B(Yamagata) viruses. Adjusted VE for influenza A(H3N2), driven by a predominant subgroup of clade 3C.2a viruses with T131K + R142K + R261Q substitutions, was low at 17% (95% confidence interval (CI): -14 to 40).

Beyond Antigenic Match: Possible Agent-Host and Immuno-epidemiological Influences on Influenza Vaccine Effectiveness During the 2015-2016 Season in Canada.

Background: Vaccine effectiveness (VE) estimates for 2015-2016 seasonal influenza vaccine are reported from Canada's Sentinel Practitioner Surveillance Network (SPSN). This season was characterized by a delayed 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) epidemic and concurrent influenza B(Victoria) virus activity. Potential influences on VE beyond antigenic match are explored, including viral genomic variation, birth cohort effects, prior vaccination, and epidemic period.

Age-Related Differences in Influenza B Infection by Lineage in a Community-Based Sentinel System, 2010-2011 to 2015-2016, Canada.

Age-related differences in influenza B lineage detection were explored in the community-based Canadian Sentinel Practitioner Surveillance Network (SPSN) from 2010-2011 to 2015-2016. Whereas >80% of B(Victoria) cases were <40 years old, B(Yamagata) cases showed a bimodal age distribution with 27% who were <20 years old and 61% who were 30-64 years old, but with a notable gap in cases between 20 and 29 years old (4%). Overall, the median age was 20 years lower for B(Victoria) vs B(Yamagata) cases (20 vs 40 years; P < .

Interim estimates of 2016/17 vaccine effectiveness against influenza A(H3N2), Canada, January 2017.

Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network (SPSN) assessed interim 2016/17 influenza vaccine effectiveness (VE) against dominant influenza A(H3N2) viruses considered antigenically matched to the clade 3C.2a vaccine strain. Sequence analysis revealed substantial heterogeneity in emerging 3C.

Serial Vaccination and the Antigenic Distance Hypothesis: Effects on Influenza Vaccine Effectiveness During A(H3N2) Epidemics in Canada, 2010-2011 to 2014-2015.

Background: The antigenic distance hypothesis (ADH) predicts that negative interference from prior season's influenza vaccine (v1) on the current season's vaccine (v2) protection may occur when the antigenic distance is small between v1 and v2 (v1 ≈ v2) but large between v1 and the current epidemic (e) strain (v1 ≠ e).

Methods: Vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza A(H3N2) illness was estimated by test-negative design during 3 A(H3N2) epidemics (2010-2011, 2012-2013, 2014-2015) in Canada. Vaccine effectiveness was derived with covariate adjustment across v2 and/or v1 categories relative to no vaccine receipt among outpatients aged ≥9 years.

Evaluation and Comparison of Multiple Test Methods, Including Real-time PCR, for Legionella Detection in Clinical Specimens.

Legionella is a Gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire's disease, a more severe illness. We aimed to compare the performance of urine antigen, culture, and polymerase chain reaction (PCR) test methods and to determine if sputum is an acceptable alternative to the use of more invasive bronchoalveolar lavage (BAL). Data for this study included specimens tested for Legionella at Public Health Ontario Laboratories from 1st January, 2010 to 30th April, 2014, as part of routine clinical testing.

A Perfect Storm: Impact of Genomic Variation and Serial Vaccination on Low Influenza Vaccine Effectiveness During the 2014-2015 Season.

Background: The 2014-2015 influenza season was distinguished by an epidemic of antigenically-drifted A(H3N2) viruses and vaccine components identical to 2013-2014. We report 2014-2015 vaccine effectiveness (VE) from Canada and explore contributing agent-host factors.

Methods: VE against laboratory-confirmed influenza was derived using a test-negative design among outpatients with influenza-like illness.

Interim estimates of 2015/16 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, February 2016.

Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network (SPSN) assessed interim 2015/16 vaccine effectiveness (VE) against influenza A(H1N1)pdm09 viruses. Adjusted VE showed significant protection of 64% (95% confidence interval (CI): 44-77%) overall and 56% (95%CI: 26-73%) for adults between 20 and 64 years-old against medically attended, laboratory-confirmed A(H1N1)pdm09 illness. Among the 67 A(H1N1)pdm09-positive specimens that were successfully sequenced, 62 (> 90%) belonged to the emerging genetic 6B.

Mutations acquired during cell culture isolation may affect antigenic characterisation of influenza A(H3N2) clade 3C.2a viruses.

As elsewhere, few (< 15%) sentinel influenza A(H3N2) clade 3C.2a viruses that dominated in Canada during the 2014/15 season could be antigenically characterised by haemagglutination inhibition (HI) assay. Clade 3C.

Epidemiology of Enterovirus D68 in Ontario.

In August 2014, children's hospitals in Kansas City, Missouri and Chicago, Illinois notified the Centers for Disease Control and Prevention (CDC) about increased numbers of pediatric patients hospitalized with severe respiratory illness (SRI). In response to CDC reports, Public Health Ontario Laboratories (PHOL) launched an investigation of patients being tested for enterovirus D-68 (EV-D68) in Ontario, Canada. The purpose of this investigation was to enhance our understanding of EV-D68 epidemiology and clinical features.

Acute Respiratory Infections in Travelers Returning from MERS-CoV-Affected Areas.

We examined which respiratory pathogens were identified during screening for Middle East respiratory syndrome coronavirus in 177 symptomatic travelers returning to Ontario, Canada, from regions affected by the virus. Influenza A and B viruses (23.1%) and rhinovirus (19.

Randomized evaluation of live attenuated vs. inactivated influenza vaccines in schools (RELATIVES) cluster randomized trial: Pilot results from a household surveillance study to assess direct and indirect protection from influenza vaccination.

Background: Children are key drivers of influenza transmission. Vaccinating school age children decreases influenza in the community.

Objective: To pilot-test the methods for a future trial to compare the direct and indirect benefits of inactivated influenza vaccine (IIV) vs.

Integrated Sentinel Surveillance Linking Genetic, Antigenic, and Epidemiologic Monitoring of Influenza Vaccine-Virus Relatedness and Effectiveness During the 2013-2014 Influenza Season.

Background: Canada's Sentinel Physician Surveillance Network links genetic, antigenic, and vaccine effectiveness (VE) measures in an integrated platform of influenza monitoring, described here for the 2013-2014 influenza season of resurgent A(H1N1)pdm09 and late-season type B activity.

Methods: VE was estimated as [1 - odds ratio] × 100% and compared vaccination status between individuals who tested positive (cases) and those who tested negative (controls) for influenza virus. Vaccine-virus relatedness was assessed by genomic sequence analysis and hemagglutination inhibition assays.

Randomized evaluation of live attenuated vs. inactivated influenza vaccines in schools (RELATIVES) pilot study: a cluster randomized trial.

Background: School-based influenza immunization can effectively address accessibility barriers, but injected inactivated influenza vaccines (IIV) may not be acceptable to some children and parents in school settings.

Objectives: To better understand the feasibility of offering intranasal live attenuated influenza vaccines (LAIV) through schools, we assessed uptake, stakeholder acceptability, and cost of school-based delivery of LAIV compared to IIV.

Methods: We piloted an open-label cluster randomized trial involving 10 elementary schools in Peterborough, Ontario during the 2013-2014 influenza vaccination campaign.

Performance of rapid influenza diagnostic testing in outbreak settings.

Rapid influenza diagnostic tests (RIDTs) may be useful during institutional respiratory disease outbreaks to identify influenza and enable antivirals to be rapidly administered to patients and for the prophylactic treatment of those exposed to the virus but not yet symptomatic. The performance of RIDTs at the outbreak level is not well documented in the literature. This study aimed to evaluate the performance of RIDTs in comparison with that of real-time reverse transcription (rRT)-PCR in the context of institutional respiratory disease outbreaks.

Coxsackieviruses in ontario, january 2005 to december 2011.

Background: In 2010, there was an increase in enterovirus meningitis in the province of Ontario, Canada. Concurrently, there was also an increase in coxsackievirus A9-positive specimens in Alberta, Canada. This study aimed to describe the results of an investigation into the increase in coxsackievirus (A9 serotype) in 2010 in Ontario.

Low 2012-13 influenza vaccine effectiveness associated with mutation in the egg-adapted H3N2 vaccine strain not antigenic drift in circulating viruses.

Background: Influenza vaccine effectiveness (VE) is generally interpreted in the context of vaccine match/mismatch to circulating strains with evolutionary drift in the latter invoked to explain reduced protection. During the 2012-13 season, however, detailed genotypic and phenotypic characterization shows that low VE was instead related to mutations in the egg-adapted H3N2 vaccine strain rather than antigenic drift in circulating viruses.

Methods/findings: Component-specific VE against medically-attended, PCR-confirmed influenza was estimated in Canada by test-negative case-control design.

Influenza A/subtype and B/lineage effectiveness estimates for the 2011-2012 trivalent vaccine: cross-season and cross-lineage protection with unchanged vaccine.

Background: We estimate vaccine effectiveness (VE) against both influenza A/subtypes and B/lineages in Canada for the 2011-2012 trivalent inactivated influenza vaccine (TIV) with components entirely unchanged from the 2010-2011 TIV and in the context of phenotypic and genotypic characterization of circulating viruses.

Methods: In a test-negative case-control study VE was estimated as [1-(adjusted)OddsRatio] × 100 for RT-PCR-confirmed influenza in vaccinated vs nonvaccinated participants. Viruses were characterized by hemagglutination inhibition (HI) and sequencing of antigenic sites of the hemagglutinin (HA) gene.