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.

BackgroundThe 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.MethodsNasal 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.ResultsThere 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%).ConclusionThe 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.

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H erpes zoster, characterized by dermatomal pain and rash, 1,2 affects about 1 of every 3 persons during their lifetime. 3-5 The most common complication is longlasting debilitating pain, known as postherpetic neuralgia, which occurs in about 8% to 27% of individuals with herpes zoster. 6-10 Given that postherpetic neuralgia has a substantial negative impact on health-related quality of life 11 and that therapeutic options are only partially effective, 12 the best option remains the prevention of herpes zoster and thus postherpetic neuralgia. 13 Two herpes zoster vaccines are currently authorized for use in Canada among adults aged 50 years or older: the recombinant subunit zoster vaccine (Shingrix) and the live attenuated zoster vaccine (Zostavax). The recombinant vaccine was approved recently (October 2017), whereas the live vaccine has been available since 2008. Clinical trials have shown that the recombinant vaccine is highly effective against herpes zoster and postherpetic neuralgia for adults aged 50 years or older (vaccine efficacy against herpes zoster 96.6% for those 50-59 yr and 97.9% for those > 70 yr) with no evidence of waning protection after 4 years. 14 Recent immunogenicity data also suggest that the immune response is maintained up to 9 years after vaccination. 15 Conversely, clinical trials and observational data have suggested that the efficacy of the live vaccine against herpes zoster decreases with older age at vaccination (from 65.5% for those 60-69 yr to 55.4% for those ≥ 70 yr 10) and wanes with increasing time since vaccination. 16-18 Although the recombinant vaccine appears to be more effective, particularly among older adults, a 2-dose schedule is recommended, compared with a 1-dose schedule for the live vaccine; this difference has implications for costs and vaccination logistics. Furthermore, although both vaccines have been shown to be safe, a significantly higher proportion of adults vaccinated RESEARCH HEALTH SERVICES

BackgroundIn 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.MethodologyIMD 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.ResultsYearly 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.ConclusionImportant 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.