Hospitalisation for lower respiratory tract infection in children in the province of Quebec, Canada, before and during the pneumococcal conjugate vaccine era.

Streptococcus pneumoniae is an important cause of community-acquired pneumonia and pneumococcal conjugate vaccines (PCVs) may reduce this burden. This study's goal was to analyse trends in lower respiratory tract infections (LRTI) hospitalisations before and during a routine vaccination programme targeting all newborns with PCV was started in the province of Quebec, Canada in December 2004. The study population included hospital admissions with a main diagnosis of LRTI among 6-59 month-old Quebec residents from April 2000 to December 2014. Trends in proportions and rates were analysed using Cochran-Armitage tests and Poisson regression models. We observed a general downward trend in all LTRI hospitalisations rate: from 11·55/1000 person-years in 2000-2001 to 9·59/1000 in 2013-2014, a 17·0% reduction, which started before the introduction of PCV vaccination. Downward trends in hospitalisation rates were more pronounced for all-cause of pneumonia (minus 17·8%) than for bronchiolitis (minus 15·4%). There was also a decrease in the mean duration of hospital stay. There was little evidence that all-cause pneumonia decreased over the study period due mainly to the introduction of PCVs. Trends may be related to changes in clinical practice. This study casts doubt on the interpretation of ecological analyses of the implementation of PCV vaccination programmes.

Forecasting Trends in Invasive Pneumococcal Disease among Elderly Adults in Quebec.

Background. In Canada, the current recommendation is to offer PPV23 to adults ≥ 65 years. PCV13 is now licensed for adults. Methods. Invasive pneumococcal disease (IPD) cases in adults 65-74 years of age in the Quebec notifiable diseases registry were classified into five serotype categories. Poisson regression models were fitted to monthly rates observed in 2000-2014 and predictions were made for 2015-2024, using theoretical assumptions regarding indirect effects of childhood vaccination and serotype replacement. Results. IPD rates caused by PCV7 serotypes decreased markedly since PCV7 introduction for children in December 2004. This trend is also underway for additional PCV13 serotypes except serotype 3. Additional PPV23 serotypes and nonvaccine serotypes have been on rise since 2004 and this is expected to continue. A small decrease in overall IPD incidence in the next decade is predicted. The proportion of PCV13 serotypes represented 33% of IPD cases in 2014 and would be 20% (95% CI: 15% to 28%) in 2024. PPV23 coverage was 53% in 2014 and is expected to be 47% (95% CI: 26% to 85%) in 2024. Conclusion. The potential usefulness of a combined PCV13 + PPV23 program for elderly adults would decrease over time but PCV13 would be the only option to prevent serotype 3 IPD.

Predictors of hospitalization for lower respiratory tract infection in children aged <2 years in the province of Quebec, Canada.

Young age, adverse environmental conditions and infectious agents are established risk factors of lower respiratory tract infection (LRTI), whereas pneumococcal conjugate vaccines may be protective. To explore their relative role as predictors of hospitalizations under the continental climate prevailing in the province of Quebec, Canada, an ecological study was performed. Records with a main diagnosis of LRTI in children born during 2007-2010 and observed up to their second-year anniversary were extracted from the provincial hospital administrative database. Respiratory virus surveillance data and statistics on ambient air temperature were obtained. Vaccine use in different birth cohorts was derived from the Quebec City Immunization Registry. Additive and multiplicative Poisson regression models were applied to estimate attributable fractions. Age, month of birth, ambient temperature, and respiratory syncytial virus (RSV), human metapneumovirus (hMPV) and influenza-positive test proportions were significant predictors of LRTI hospitalizations. No substantial differences were observed in cohorts exposed to the 7-valent or 10-valent pneumococcal conjugate vaccines. In the additive model, the fraction of hospitalizations explained by temperature variation was 37%, whereas RSV circulation explained 28%, hMPV 4% and influenza 1%. Complex interplay between biological, environmental and social mechanisms may explain the important role of ambient air temperature in predicting LRTI hospitalization risk in young children.

Impact of a mass vaccination campaign against Serogroup B meningococcal disease in the Saguenay-Lac-Saint-Jean region of Quebec four years after its launch.

In the Saguenay-Lac-Saint-Jean region of Quebec, 83% of the population ≤20 years (n ≅ 59,500) was immunized in 2014 with the four-component Serogroup B meningococcal vaccine to control a long-lasting outbreak caused by a virulent ST-269 Serogroup B Neisseria meningitidis clone. Following the campaign, invasive meningococcal B disease (B-IMD) incidence fell sharply in the target population from 11.4/100,000 in 2006-2014 to 0.4/100,000 in 2014-2018 (p < 0.0001). Five B-IMD cases occurred in the region from July 2014 to June 2018, including one vaccinated child, one unvaccinated young adult and 3 unvaccinated elderly adults. Estimate of direct vaccine protection was 79% [95%CI:-231%;99%]. The overall campaign impact in the region taking into account the decrease in B-IMD incidence at provincial level was a 86% [95%CI:-2%;98%] decrease in B-IMD risk. The campaign impact was mostly seen in the target age-group suggesting no herd effect among unvaccinated older adults.

Most ten-year-old children with negative or unknown histories of chickenpox are immune.

To evaluate the proportion of children to vaccinate against varicella in a catch-up program targeting 9- to 10-year-old children, a study was conducted among children age 10 years to assess the age-specific incidence of varicella and document the immunity against varicella in those with negative or unknown chickenpox history. Of the latter 62% were seropositive for varicella.

Opinions of Quebec parents and vaccinators on the usefulness of chickenpox vaccine.

BACKGROUND: A chickenpox vaccine was recently licensed in Canada. Because this vaccine has caused some controversy within the health care profession, studies among Quebec parents and vaccine providers were carried out, surveying their opinions concerning chickenpox vaccination. METHODS: Three studies among parents of preadolescents, parents of two-year-old children completely or incompletely vaccinated and vaccinators were completed. The studies asked for opinions concerning the usefulness of vaccinating children against chickenpox. RESULTS: The majority of parents of preadolescents (56%), and parents of two-year-old children completely (64%) and incompletely vaccinated (60%) favoured chickenpox vaccination. Among vaccinators, 53% of paediatricians, 37% of general practitioners and 33% of nurses considered universal vaccination of young children to be useful. A greater proportion of health care professionals were in favour of a policy of vaccinating groups at risk, such as susceptible adolescents (86%, 75% and 58%, respectively). There was a positive association between the perceived severity of chickenpox and the potential usefulness of the vaccine. CONCLUSION: Quebec parents are more favourably disposed to chickenpox vaccine than vaccine providers. In contrast, strategies targeting susceptible groups would be generally well received by health care professionals. A considerable amount of work will be needed to convince vaccinators of the benefits of a universal childhood vaccination against chickenpox.

Improvement of clinical algorithms for the diagnosis of Neisseria gonorrhoeae and Chlamydia trachomatis by the use of Gram-stained smears among female sex workers in Accra, Ghana.

BACKGROUND: Screening for cervical infection is difficult in developing countries. Screening strategies must be improved for high-risk women, such as female sex workers. GOAL: To evaluate the sensitivity and specificity of screening algorithms for cervical infection pathogens among female sex workers in Accra, Ghana. STUDY DESIGN: A cross-sectional study among female sex workers was conducted. Each woman underwent an interview and a clinical examination. Biologic samples were obtained for the diagnosis of HIV, syphilis, bacterial vaginosis, yeast infection, Trichomonas vaginalis, Neisseria gonorrhoeae, and Chlamydia trachomatis infection. Signs and symptoms associated with cervicitis agents were identified. Algorithms for the diagnosis of cervical infection were tested by computer simulations. RESULTS: The following prevalences were observed: HIV, 76.6%; N. gonorrhoeae, 33.7%; C. trachomatis, 10.1%; candidiasis, 24.4%; T. vaginalis, 31.4%; bacterial vaginosis, 2.3%; serologic syphilis, 4.6%; and genital ulcers on clinical examination, 10.6%. The best performance of algorithms were reached when using a combination of clinical signs and a search for gram-negative diplococci on cervical smears (sensitivity, 64.4%; specificity, 80.0%). CONCLUSIONS: In the algorithms, examination of Gram-stained genital smears in female sex workers without clinical signs of cervicitis improved sensitivity without altering specificity for the diagnosis of cervical infection.

HIV infection among sex workers in Accra: need to target new recruits entering the trade.

OBJECTIVE: Description of the epidemiology of HIV infection among sex workers (SW) in Accra, Ghana. METHODS: In all, 1013 SW working out of their homes ( seaters ) or finding customers in bars, hotels, brothels or on the street ( roamers ) were interviewed and tested for HIV. RESULTS: Overall, prevalence of HIV infection was nearly 50% (506 of 1013), varying from 26% (133 of 507) among the roamers to 74% (368 of 496) among the seaters. Profound differences were noted between these two categories of SW with regard to age, number of clients per day, price per instance of intercourse, condom use, and other characteristics. Respectively, 27% and 58% of roamers and seaters were infected with HIV within their first 6 months of sex work, despite a limited number of unprotected sex acts with seropositive clients. Independent risk factors for HIV infection varied between types of SW: age among the roamers; region of origin and duration of sex work among the seaters; number of clients per day, and presence of current or past genital ulcer and gonococcal cervicitis in both groups. CONCLUSION: In Accra, considerable heterogeneity exists in the population of SWs. In both categories of SW, new recruits become rapidly infected with HIV after entering the trade. The 25-fold higher prevalence of HIV among SWs than in the general adult population suggests that in Accra, as in many cities of West Africa, a high fraction of new cases of HIV infection continue to be acquired from SWs. Intervention programs targeting SW should be an essential component of national AIDS control strategies. Special efforts should be made to identify and offer preventive services to new sex workers.