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A vaccine for respiratory syncytial virus (RSV) has been actively sought for over 60 years due to the health impacts of RSV disease in infants, but currently the only available preventive measure in Canada and elsewhere is limited to passive immunization for high-risk infants and children with a monoclonal antibody. RSV vaccine development has faced many challenges, including vaccine-induced enhancement of RSV disease in infants. Several key developments in the last decade in the fields of cellular immunology and protein structure have led to new products entering late-stage clinical development. As of July 2019, RSV vaccine development is being pursued by 16 organizations in 121 clinical trials. Five technologies dominate the field of RSV vaccine development, four active immunizing agents (live-attenuated, particle-based, subunit-based and vector-based vaccines) and one new passive immunizing agent (monoclonal antibody). Phase 3 clinical trials of vaccine candidates for pregnant women, infants, children and older adults are under way. The next decade will see a dramatic transformation of the RSV prevention landscape.

Introduction Real-time polymerase chain reaction (PCR) is the preferred method for the diagnosis of pertussis. In Quebec, positive and equivocal results are reportable to public health; in contrast, in Ontario equivocal results are not reportable. Objective To determine the clinical significance of equivocal, compared with positive results, in children with suspected pertussis. Methods Retrospective cohort of consecutive patients seen at the Centre Hospitalier Universitaire Sainte-Justine in Montreal, Quebec, with suspected pertussis and tested with a bacterial multiplex PCR (including Bordetella pertussis) between 2015 and 2017. Medical records were reviewed using a standardized form. Univariate analyses (Student's t-test and chi-square test) and multivariable logistic regression were used to compare cases of positive and equivocal results. Results Of the 1,526 multiplex PCR performed, 109 were positive and 24 equivocal. Both groups were similar in terms of demographics and disease severity assessments, but patients in the equivocal group had less paroxysmal cough (33.3% vs 79.8%, adjusted odds ratio [aOR] 0.11, 95% confidence interval [CI] 0.04-0.29) and whoop (0% vs 18.3%, p

Background The introduction of the acellular pertussis vaccine may have changed the epidemiological and clinical features of pertussis in Canadian children. Objective To describe the demographics, clinical presentation and outcomes of children and adolescents with pertussis presenting to a tertiary care hospital. Methods Retrospective cohort of consecutive patients evaluated at the Centre Hospitalier Universitaire Sainte-Justine (CHUSJ) and tested with a bacterial multiplex real-time polymerase chain reaction (PCR) for Bordetella pertussis or B. parapertussis between June 2015 and March 2017. Demographics, clinical presentations and outcomes were described for positive test results. The Modified Preziosi Scale was used to assess disease severity; severe disease was defined as a score ≥7. Results The age distribution of the 144 positive patients with a clinical encounter at CHUSJ was as follows: less than three months (n=25/144, 17.4%), four months to nine years (n=63/144, 43.8%) and 10 to 18 years (n=56/144, 38.9%). The most common symptoms at presentation were paroxysmal cough (70.1%), post-tussive emesis (47.2%) and coryza (33.3%). Over 84.0% of cases in infants less than three months of age had severe pertussis (92.0% required hospitalization and 28.0% intensive care admission). In children four months to nine years of age, 22.2% had severe pertussis and 11.1% required hospitalization. Only two (3.6%) children greater than 10 years had severe disease. Conclusion Pertussis still affects children of all ages in Quebec. In older children, it tends to be a milder disease. When it affects infants, who do not yet have full protection from pertussis vaccination, it often causes severe disease, especially in those less than three months of age. This evidence further supports the implementation of a pertussis vaccination program in pregnant women.

Background Individuals who are 2 years of age and over and at high risk for invasive pneumococcal disease (IPD) (defined as those with functional or anatomic asplenia or sickle cell disease; hepatic cirrhosis; chronic renal failure or nephrotic syndrome; HIV infection; and immunosuppression related to disease or therapy) are recommended to receive one lifetime booster dose of polysaccharide 23-valent pneumococcal vaccine (Pneu-P-23) vaccine, in addition to age- and risk-specific recommendations for the conjugate 13-valent pneumococcal vaccine (Pneu-C-13). Adults aged 65 years and over are also considered at high risk for invasive pneumococcal disease (IPD). Objective To determine the optimal time between initial vaccination with Pneu-P-23 and subsequent booster doses to protect against IPD in those at high risk for IPD. Methods The National Advisory Committee on Immunization (NACI) conducted a systematic review of the literature on booster doses of pneumococcal vaccine for individuals at high risk for IPD disease. NACI reviewed the evidence considering the target population, safety, immunogenicity, efficacy, effectiveness of the vaccines, vaccine schedules, and other aspects of the overall immunization strategy, and then approved three specific recommendations. Results For all individuals aged 2 years and over who are at high risk for IPD and who have received a dose of Pneu-P-23, re-vaccination with a second dose of Pneu-P-23 should be provided five years after the initial dose of Pneu-P-23. They should also have previously received age-appropriate doses of 13-valent conjugate pneumococcal vaccine. There is currently insufficient evidence to determine the optimal timing and number of Pneu-P-23 boosters in high-risk adults. One lifetime booster of Pneu-P-23 is currently recommended for individuals at high risk for IPD, five years after the previous dose. Given the increased risk of IPD in adults aged 65 years and older and the rapid decline in antibodies following Pneu-P-23, all individuals should receive one dose of Pneu-P-23 at age 65 years-as long as five years have passed since the previous Pneu-P-23 dose. No additional booster dose is currently recommended for this age group, if they have no medical conditions that put them at high risk for IPD. Conclusion The new and complete set of current recommendations for pneumococcal vaccines will be published in the updated "Pneumococcal" chapter in the Canadian Immunization Guide in the near future.

The National Advisory Committee on Immunization (NACI) develops recommendations for the use of vaccines for Canadians, which are summarized in the Canadian Immunization Guide (the Guide) and which is updated on a regular basis. Between March 2014 and February 2015 recommendations on five vaccines have been issued. Updates to the Guide include recommendations made for the alternative dosing administration of the human papillomavirus (HPV) vaccine in adolescents, timing of varicella zoster immune globulin (VarIg) following exposure to varicella, and the meningococcal and quadrivalent influenza vaccines, recently authorized for use in Canada. A change in recommendations for the use of pneumococcal vaccines in adults and individuals with asthma has also been made. The chapter on tick-borne encephalitis vaccine has now been removed from the Guide as this vaccine is no longer available in Canada.