Declining rates of cervical intraepithelial neoplasia in British Columbia, Canada: An ecological analysis on the effects of the school-based human papillomavirus vaccination program.

Since 2008, girls in British Columbia (BC), Canada, have been offered HPV vaccination through a school-based, publicly funded immunization program. The oldest birth cohort eligible for the vaccination program was born in 1994 and uptake is on average 63%. To evaluate the impact of the HPV vaccine in BC, ecological trends in cervical intraepithelial neoplasia (CIN) rates were assessed in young women before and after the implementation of the HPV vaccination program. Information on all Pap smears and histopathological abnormalities, in calendar years 2004-2017 in women 16-28 years of age in BC were obtained from the population-based BC Cancer Cervix Screening Program database. Rates of CIN 2 and 3 were calculated as the number of cases divided by the number of cytology specimens for that period. Rate ratios (RR) were calculated by negative binomial piecewise regression. Age-centered incidence rates of CIN 2 and 3 in BC declined significantly among women 16-23 years of age after HPV vaccine introduction compared to before vaccine introduction. The overall reduction postvaccination for CIN2 and 3 in women 16-23 years was respectively 62% (95% CI 54-68%) and 65% (95% CI 58-71%). Age-specific rates for CIN2 significantly declined for those 18-22 years of age and for those 19, 20 and 23 years of age for CIN3. Among women 24-28 years of age no decline in CIN2 and 3 rate over time was observed. The observed reduction in CIN 2 and 3 rates since the introduction of the school-based HPV vaccine program might illustrate the population impact of the BC provincial school-based HPV vaccination program.

Immunogenicity of 2 and 3 Doses of the Quadrivalent Human Papillomavirus Vaccine up to 120 Months Postvaccination: Follow-up of a Randomized Clinical Trial.

BACKGROUND: Several countries have implemented a 2-dose (2D) human papillomavirus (HPV) vaccination schedule for adolescents based on immunobridging studies. We compared immunogenicity of 2D vs 3-dose (3D) schedules of the quadrivalent vaccine (4vHPV) up to 10 years after the first dose. METHODS: Girls aged 9-13 years were randomized to receive 2D or 3D and were compared with women aged 16-26 receiving 3D at day 1 and months 7, 24, and 120 after the first dose. Antibody levels for HPV6/11/16/18 were evaluated using the competitive Luminex immunoassay (cLIA) and total immunoglobulin G assay. Geometric mean titers (GMTs) and seropositivity rates were compared between the different groups at different time points. Noninferiority of GMT ratios was defined as the lower bound of the 2-sided 95% confidence interval (CI) being greater than 0.5. Kinetics of antibody titers over time among study groups were examined. RESULTS: At 120 months, data from 35 2D girls, 38 3D girls, and 30 3D women were used for analyses. cLIA seropositivity rates were above 95% for all HPV vaccine types and all schedules, except HPV18, with the lowest seropositivity observed among 3D women (60.0%; 95% CI, 40.6%-77.3%). GMT ratios (cLIA) for both 2D and 3D girls were noninferior to 3 doses in women for HPV6/11/16/18. Trends were comparable between assays. CONCLUSIONS: GMTs for HPV6/11/16/18 after 2D or 3D of 4vHPV in girls were noninferior to 3D in adult women up to 120 months postvaccination. This study demonstrates long-term immunogenicity of the 2D HPV vaccine schedule.

Modelling the effects of environmental heterogeneity within the lung on the tuberculosis life-cycle.

Progress in shortening the duration of tuberculosis (TB) treatment is hampered by the lack of a predictive model that accurately reflects the diverse environment within the lung. This is important as TB has been shown to produce distinct localisations to different areas of the lung during different disease stages, with the environmental heterogeneity within the lung of factors such as air ventilation, blood perfusion and oxygen tension believed to contribute to the apical localisation witnessed during the post-primary form of the disease. Building upon our previous model of environmental lung heterogeneity, we present a networked metapopulation model that simulates TB across the whole lung, incorporating these notions of environmental heterogeneity across the whole TB life-cycle to show how different stages of the disease are influenced by different environmental and immunological factors. The alveolar tissue in the lung is divided into distinct patches, with each patch representing a portion of the total tissue and containing environmental attributes that reflect the internal conditions at that location. We include populations of bacteria and immune cells in various states, and events are included which determine how the members of the model interact with each other and the environment. By allowing some of these events to be dependent on environmental attributes, we create a set of heterogeneous dynamics, whereby the location of the tissue within the lung determines the disease pathological events that occur there. Our results show that the environmental heterogeneity within the lung is a plausible driving force behind the apical localisation during post-primary disease. After initial infection, bacterial levels will grow in the initial infection location at the base of the lung until an adaptive immune response is initiated. During this period, bacteria are able to disseminate and create new lesions throughout the lung. During the latent stage, the lesions that are situated towards the apex are the largest in size, and once a post-primary immune-suppressing event occurs, it is the uppermost lesions that reach the highest levels of bacterial proliferation. Our sensitivity analysis also shows that it is the differential in blood perfusion, causing reduced immune activity towards the apex, which has the biggest influence of disease outputs.

Unusual accumulation of a wide array of antimicrobial resistance mechanisms in a patient with cytomegalovirus-associated hemophagocytic lymphohistiocytosis: a case report.

BACKGROUND: Infections with multidrug-resistant organisms (MDRO) pose a serious threat to patients with dysregulated immunity such as in hemophagocytic lymphohistiocytosis (HLH), but such infections have rarely been comprehensively characterized. Here, we present a fatal case of HLH secondary to cytomegalovirus (CMV) infection complicated by both anti-viral drug resistance and sepsis from multiple MDROs including pandrug-resistant superbug bacteria. CASE PRESENTATION: A previously healthy, six-year-old boy presented with a 45-day history of fever prior to a diagnosis of hemophagocytic lymphohistiocytosis and hemorrhagic colitis, both associated with CMV. On hospital admission, the patient was found to be colonized with multiple, multidrug-resistant (MDR) bacteria including vancomycin-resistant enterococci (VRE) and carbapenamase-producing organisms (CPO). He eventually developed respiratory, urine and bloodstream infections with highly drug-resistant, including pandrug-resistant bacteria, which could not be controlled by antibiotic treatment. Antiviral therapy also failed to contain his CMV infection and the patient succumbed to overwhelming bacterial and viral infection. Whole genome sequencing (WGS) of the MDR bacteria and metagenomic analysis of his blood sample revealed an unusual accumulation of a wide range of antimicrobial resistance mechanisms in a single patient, including antiviral resistance to ganciclovir, and resistance mechanisms to all currently available antibiotics. CONCLUSIONS: The case highlights both the risk of acquiring MDR superbugs and the severity of these infections in HLH patients.

Pediatric oncology and stem cell transplant patients with healthcare-associated Clostridium difficile infection were already colonized on admission.

Clostridium difficile is the leading cause of healthcare-associated infections worldwide. The diagnosis of C. difficile infection (CDI) in pediatric oncology patients is complex as diarrhea is common, and there is a high rate of colonization in infants and young children. This study was conducted to assess the accuracy of the surveillance definitions of healthcare-associated CDI (HA-CDI) and to determine the prevalence of toxigenic C. difficile colonization among pediatric oncology and stem cell transplant patients. METHODS: A prospective cohort study was conducted over a three-year period in an inpatient pediatric oncology and stem cell transplant setting. Baseline stool samples were collected within three days of admission and were genotypically compared with clinically indicated samples submitted after three days of admission. RESULTS: A total of 175 patients were recruited with a total of 536 admissions. The adjusted prevalence of baseline toxigenic C. difficile colonization among admissions was 32.8%. Seventy-eight percent of positive admissions did not have history of CDI. Colonization with a toxigenic strain on admission was predictive of CDI (OR = 28.6; 95% CI, 6.58-124.39; P < 0.001). Nearly all clinical isolates (8/9) shared identical pulsed-field gel electrophoresis patterns with baseline isolates or were closely related (1/9). Only one of the 11 cases that were considered HA-CDI was potentially nosocomially acquired. CONCLUSION: The prevalence of colonization with toxigenic C. difficile in our cohort is high. Unfortunately, the current CDI surveillance definitions overestimate the incidence of HA-CDI in pediatric oncology and stem cell transplantation settings.

A Randomized Controlled Trial of the Safety and Immunogenicity of Tetanus, Diphtheria, and Acellular Pertussis Vaccine Immunization During Pregnancy and Subsequent Infant Immune Response.

Background: Immunization of pregnant women with tetanus-diphtheria-acellular pertussis vaccine (Tdap) provides protection against pertussis to the newborn infant. Methods: In a randomized, controlled, observer-blind, multicenter clinical trial, we measured the safety and immunogenicity of Tdap during pregnancy and the effect on the infant's immune response to primary vaccination at 2, 4, and 6 months and booster vaccination at 12 months of age. A total of 273 women received either Tdap or tetanus-diphtheria (Td) vaccine in the third trimester and provided information for the safety analysis and samples for the immunogenicity analyses; 261 infants provided serum for the immunogenicity analyses. Results: Rates of adverse events were similar in both groups. Infants of Tdap recipients had cord blood levels that were 21% higher than maternal levels for pertussis toxoid (PT), 13% higher for filamentous hemagglutinin (FHA), 4% higher for pertactin (PRN), and 7% higher for fimbriae (FIM). These infants had significantly higher PT antibody levels at birth and at 2 months and significantly higher FHA, PRN, and FIM antibodies at birth and 2 and 4 months, but significantly lower PT and FHA antibody levels at 6 and 7 months and significantly lower PRN and FIM antibody levels at 7 months than infants whose mothers received Td. Differences persisted prebooster at 12 months for all antigens and postbooster 1 month later for PT, FHA, and FIM. Conclusions: This study demonstrated that Tdap during pregnancy results in higher levels of antibodies early in infancy but lower levels after the primary vaccine series. Clinical Trials Registration: NCT00553228.

Population-level sexual behaviours in adolescent girls before and after introduction of the human papillomavirus vaccine (2003-2013).

BACKGROUND: The human papillomavirus (HPV) vaccine is delivered widely through school-based immunization programs. Some groups have expressed concern that HPV vaccination programs will result in an increase in sexual risk-taking behaviours among adolescents. We aimed to evaluate population-level changes in sexual behaviours before and after implementation of the school-based HPV vaccination program in British Columbia. METHODS: In 2008, a school-based HPV vaccination program for girls was introduced in British Columbia. Using data from the BC Adolescent Health Survey - a longitudinal provincial survey administered in schools to capture adolescent physical and emotional health indicators, we conducted a linear trend analysis on sexual health behaviours and risk factors in adolescent girls before and after the implementation of vaccination for HPV (2003, 2008 and 2013). RESULTS: We analyzed data for 298 265 girls who self-identified as heterosexual. The proportion of girls reporting ever having sexual intercourse decreased from 21.3% (2003) to 18.3% (2013; adjusted odds ratio [OR] 0.79). Self-report of sexual intercourse before the age of 14 years decreased significantly from 2008 to 2013 (adjusted OR 0.76), as did reported substance use before intercourse (adjusted OR for 2003-2013 0.69). There was no significant change in the number of sexual partners reported (2003-2013). Between 2003 and 2013, girls' reported use of contraception and condoms increased, while pregnancy rates decreased. INTERPRETATION: Since the implementation of school-based HPV vaccination program in BC, sexual risk behaviours reported by adolescent girls either reduced or stayed the same. These findings contribute evidence against any association between HPV vaccination and risky sexual behaviours.

Reduction in cervical intraepithelial neoplasia in young women in British Columbia after introduction of the HPV vaccine: An ecological analysis.

We report on the rates of cervical intraepithelial neoplasia (CIN) in young women aged 15-22 years of age in British Columbia before and after the introduction of an HPV vaccine program. Rates of cervical intraepithelial neoplasia (CIN) 2+ for each age stratum (15-22) in the calendar years 2004-2012 for the province of British Columbia were obtained from the BC Cancer Agency's population-based cervical cancer program. Incidence rate ratios (IRR) of CIN2+ were described and compared before and after HPV vaccine program introduction in cohorts born in vaccine eligible years, and in non-vaccine eligible years using piece-wise Poisson regression analysis, and adjusted for age. Between 2004 and 2012, rates of CIN2 and CIN2+ in young women aged 15-22 years in the province of British Columbia have decreased overall. After the introduction of the HPV vaccine program, the age adjusted IRR for CIN2+ for young women aged 15-17 years decreased significantly from 0.91 (95% CI: 0.86-0.98 p < 0.01) to 0.36 (95% CI: 0.18-0.73 p < 0.01). During the same time period, no similar reduction was found in young women 18-22 years. After introduction of HPV vaccine program, IRR for CIN2+ in young women 15-17 was significantly reduced for CIN2+ (0.14; 95% CI: 0.04- 0.47; p < 0.01) and CIN2 (0.1; 95% CI: 0.02-0.54; p < 0.01). This ecological analysis shows a significant reduction in CIN2+ lesions in young women aged 15-17 years in British Columbia after the introduction of the HPV vaccine in young women despite vaccine uptake levels below 70%.

The role of pediatricians as key stakeholders in influencing immunization policy decisions for the introduction of meningitis B vaccine in Canada: The Ontario perspective.

As key stakeholders in immunization policy decisions, the Pediatricians of Ontario held an accredited conference on January 18, 2014, to discuss prevention of invasive meningococcal disease. Five key recommendations were put forth regarding immunization strategies to protect children from meningococcal serogroup B disease. The recently approved four-component meningococcal B (4CMenB) vaccine should be recommended and funded as part of Ontario's routine immunization schedule and should also be mandated for school attendance. Public funding for 4CMenB immunization is justified based on current MenB epidemiology, vaccine coverage, cost effectiveness and acceptability, as well as legal, political and ethical considerations related to 4CMenB immunization, particularly because routine recommendations and funding are currently in place for vaccination against meningococcal serogroups that cause significantly less disease in Canada than MenB. Broadly, the goals are to assist individual practitioners in advocating the benefits of 4CMenB vaccination to parents, and to counterbalance recommendations from the National Advisory Committee on Immunization and the Canadian Paediatric Society.

À titre de principaux intervenants à l'égard des décisions relatives aux politiques de vaccination, les Pediatricians of Ontario a organisé un colloque agréé le 18 janvier 2014 pour discuter de la prévention des méningococcies invasives. Il a formulé cinq grandes recommandations sur les stratégies de vaccination pour protéger les enfants des méningococcies du sérogroupe B (MenB). Le vaccin contre le méningocoque de sérogroupe B (4CMenB) qui a récemment été approuvé devrait être recommandé et financé dans le cadre du calendrier de vaccination systématique de l'Ontario et être exigé pour pouvoir fréquenter l'école. Le financement public du vaccin 4CMenB est justifié compte tenu de l'épidémiologie actuelle de la MenB, de la couverture vaccinale, de l'efficience et de l'acceptabilité, de même que des considérations juridiques, politiques et éthiques liées au vaccin 4CMenB, particulièrement parce que les recommandations et le financement de la vaccination systématique sont déjà en place au Canada contre des sérogroupes du méningocoque qui sont beaucoup moins graves que le MenB. En général, le regroupement vise ainsi à aider les praticiens à préconiser les avantages du vaccin 4CMenB auprès des parents et à compenser les recommandations du Comité consultatif national d'immunisation et de la Société canadienne de pédiatrie.

Obstetrical and neonatal outcomes among women infected with hepatitis C and their infants.

OBJECTIVES: (1) To describe obstetrical and neonatal outcomes among a cohort of hepatitis C virus (HCV) infected women, comparing HCV RNA positive to HCV RNA negative women; (2) to characterize virologic and hepatic parameters associated with HCV infection during pregnancy; and (3) to describe the rate of HCV vertical transmission. METHODS: We prospectively enrolled 145 HCV-positive pregnant women across British Columbia between 2000 and 2003. Participating women were monitored during pregnancy and their infants were followed to assess them for HCV infection. Maternal HCV RNA was assessed close to delivery. RESULTS: Seventy percent of women reported injection drug use as their primary risk factor for HCV acquisition. Observed rates of intrauterine fetal death, preterm delivery, small for gestational age, and low birth weight infants were 3.4%, 17.9%, 11.3%, and 12.5%, respectively, without a significant association with maternal HCV RNA status. The rate of cholestasis was 5.6% in the HCV RNA-positive group (6/108) and 2.8% in the HCV RNA-negative group (1/37) (P = 0.496). Serum alanine aminotransferase levels decreased significantly through pregnancy, and were significantly higher in HCV RNA-positive women than in HCV RNA-negative women after controlling for cholestasis, co-infections, and alcohol consumption. Among the HCV RNA-positive women, the median FIB-4 score was 0.67 (IQR 0.56 to 0.76) in the first trimester, 0.74 (IQR 0.52 to 1.18) in the second trimester, and 0.89 (IQR 0.52 to 1.09) in the third trimester (P = 0.02). The median HCV viral load at delivery was 424 561 IU/mL. The vertical transmission rate was 4.7% in HCV RNA-positive women, with no cases in HCV RNA-negative women. CONCLUSION: Because of the high rates of poor obstetrical outcomes found in this prospective cohort, population-level screening for HCV in pregnancy should be considered.

Objectifs : 1) Décrire les issues obstétricales et néonatales au sein d'une cohorte de femmes infectées par le virus de l'hépatite C (VHC), en comparant des femmes séropositives pour l'ARN du VHC à des femmes séronégatives pour l'ARN du VHC; 2) caractériser les paramètres virologiques et hépatiques associés à l'infection par le VHC pendant la grossesse; et 3) décrire le taux de transmission verticale du VHC. Méthodes : Nous avons sollicité, de manière prospective, la participation de 145 femmes enceintes séropositives pour le VHC provenant des quatre coins de la Colombie-Britannique, entre 2000 et 2003. Les participantes ont fait l'objet d'un suivi pendant la grossesse, tandis que leurs nouveau-nés ont été suivis afin de déterminer la présence ou non d'une infection par le VHC. La présence d'ARN du VHC chez la mère a été évaluée peu avant l'accouchement. Résultats : Soixante-dix pour cent des femmes ont indiqué que la consommation de drogues par injection constituait leur principal facteur de risque d'acquisition du VHC. Les taux constatés de mort fœtale intra-utérine, d'accouchement préterme, d'hypotrophie fœtale et de faible poids à la naissance étaient, respectivement, de 3,4 %, de 17,9 %, de 11,3 % et de 12,5 %, sans association significative avec le statut maternel quant à l'ARN du VHC. Le taux de cholestase était de 5,6 % chez les femmes séropositives pour l'ARN du VHC (6/108) et de 2,8 % chez les femmes séronégatives pour l'ARN du VHC (1/37) (P = 0,496). Les taux sériques d'alanine aminotransférase ont diminué considérablement tout au long de la grossesse et étaient nettement plus élevés chez les femmes séropositives pour l'ARN du VHC que chez les femmes séronégatives pour l'ARN du VHC, à la suite de la neutralisation des effets de la cholestase, des co-infections et de la consommation d'alcool. Chez les femmes séropositives pour l'ARN du VHC, le score FIB-4 médian était de 0,67 (IIQ 0,56 - 0,76) pendant le premier trimestre, de 0,74 (IIQ 0,52 - 1,18) pendant le deuxième trimestre et de 0,89 (IIQ 0,52 - 1,09) pendant le troisième trimestre (P = 0,02). La charge virale médiane en ce qui concerne le VHC au moment de l'accouchement était de 424 561 UI/ml. Le taux de transmission verticale était de 4,7 % chez les femmes séropositives pour l'ARN du VHC; aucun cas n'a été recensé chez les femmes séronégatives pour l'ARN du VHC. Conclusion : Compte tenu des taux élevés de piètres issues obstétricales qui sont constatés au sein de cette cohorte prospective, la mise en œuvre d'un dépistage populationnel du VHC pendant la grossesse devrait être envisagée.

Energy-efficient sensing in wireless sensor networks using compressed sensing.

Sensing of the application environment is the main purpose of a wireless sensor network. Most existing energy management strategies and compression techniques assume that the sensing operation consumes significantly less energy than radio transmission and reception. This assumption does not hold in a number of practical applications. Sensing energy consumption in these applications may be comparable to, or even greater than, that of the radio. In this work, we support this claim by a quantitative analysis of the main operational energy costs of popular sensors, radios and sensor motes. In light of the importance of sensing level energy costs, especially for power hungry sensors, we consider compressed sensing and distributed compressed sensing as potential approaches to provide energy efficient sensing in wireless sensor networks. Numerical experiments investigating the effectiveness of compressed sensing and distributed compressed sensing using real datasets show their potential for efficient utilization of sensing and overall energy costs in wireless sensor networks. It is shown that, for some applications, compressed sensing and distributed compressed sensing can provide greater energy efficiency than transform coding and model-based adaptive sensing in wireless sensor networks.

The evidence behind prophylaxis and treatment of wound infection after surgery.

Surgical site infections (SSIs) represent a serious post surgical complication. They are the leading cause of healthcare-related infections in developing countries and the second most common healthcare-related infection in developed countries. Here we discuss the epidemiology of and risk factors for SSIs together with the current evidence supporting the use of antibiotic prophylaxis for the prevention of wound infection after surgery.

Immunogenicity of 2 doses of HPV vaccine in younger adolescents vs 3 doses in young women: a randomized clinical trial.

IMPORTANCE: Global use of human papillomavirus (HPV) vaccines to prevent cervical cancer is impeded by cost. A 2-dose schedule for girls may be possible. OBJECTIVE: To determine whether mean antibody levels to HPV-16 and HPV-18 among girls receiving 2 doses was noninferior to women receiving 3 doses. DESIGN, SETTING, AND PATIENTS: Randomized, phase 3, postlicensure, multicenter, age-stratified, noninferiority immunogenicity study of 830 Canadian females from August 2007 through February 2011. Follow-up blood samples were provided by 675 participants (81%). INTERVENTION: Girls (9-13 years) were randomized 1:1 to receive 3 doses of quadrivalent HPV vaccine at 0, 2, and 6 months (n = 261) or 2 doses at 0 and 6 months (n = 259). Young women (16-26 years) received 3 doses at 0, 2, and 6 months (n = 310). Antibody levels were measured at 0, 7, 18, 24, and 36 months. MAIN OUTCOMES AND MEASURES: Primary outcome was noninferiority (95% CI, lower bound >0.5) of geometric mean titer (GMT) ratios for HPV-16 and HPV-18 for girls (2 doses) compared with young women (3 doses) 1 month after last dose. Secondary outcomes were noninferiority of GMT ratios of girls receiving 2 vs 3 doses of vaccine; and durability of noninferiority to 36 months. RESULTS: The GMT ratios were noninferior for girls (2 doses) to women (3 doses): 2.07 (95% CI, 1.62-2.65) for HPV-16 and 1.76 (95% CI, 1.41-2.19) for HPV-18. Girls (3 doses) had GMT responses 1 month after last vaccination for HPV-16 of 7736 milli-Merck units per mL (mMU/mL) (95% CI, 6651-8999) and HPV-18 of 1730 mMU/mL (95% CI, 1512-1980). The GMT ratios were noninferior for girls (2 doses) to girls (3 doses): 0.95 (95% CI, 0.73-1.23) for HPV-16 and 0.68 (95% CI, 0.54-0.85) for HPV-18. The GMT ratios for girls (2 doses) to women (3 doses) remained noninferior for all genotypes to 36 months. Antibody responses in girls were noninferior after 2 doses vs 3 doses for all 4 vaccine genotypes at month 7, but not for HPV-18 by month 24 or HPV-6 by month 36. CONCLUSIONS AND RELEVANCE: Among girls who received 2 doses of HPV vaccine 6 months apart, responses to HPV-16 and HPV-18 one month after the last dose were noninferior to those among young women who received 3 doses of the vaccine within 6 months. Because of the loss of noninferiority to some genotypes at 24 to 36 months in girls given 2 doses vs 3 doses, more data on the duration of protection are needed before reduced-dose schedules can be recommended. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00501137.

Belief propagation on networks with cliques and chordless cycles.

It is well known that tree-based theories can describe the properties of undirected clustered networks with extremely accurate results [S. Melnik et al., Phys. Rev. E 83, 036112 (2011)10.1103/PhysRevE.83.036112]. It is reasonable to suggest that a motif-based theory would be superior to a tree one, since additional neighbor correlations are encapsulated in the motif structure. In this paper, we examine bond percolation on random and real world networks using belief propagation in conjunction with edge-disjoint motif covers. We derive exact message passing expressions for cliques and chordless cycles of finite size. Our theoretical model gives good agreement with Monte Carlo simulation and offers a simple, yet substantial improvement on traditional message passing, showing that this approach is suitable to study the properties of random and empirical networks.

Degree correlations in graphs with clique clustering.

Correlations among the degrees of vertices in random graphs often occur when clustering is present. In this paper we define a joint-degree correlation function for vertices in the giant component of clustered configuration model networks which are composed of clique subgraphs. We use this model to investigate, in detail, the organization among nearest-neighbor subgraphs for random graphs as a function of subgraph topology as well as clustering. We find an expression for the average joint degree of a neighbor in the giant component at the critical point for these networks. Finally, we introduce a novel edge-disjoint clique decomposition algorithm and investigate the correlations between the subgraphs of empirical networks.

N-strain epidemic model using bond percolation.

In this paper we examine the emergent structures of random networks that have undergone bond percolation an arbitrary, but finite, number of times. We define two types of sequential branching processes: a competitive branching process, in which each iteration performs bond percolation on the residual graph (RG) resulting from previous generations, and a collaborative branching process, where percolation is performed on the giant connected component (GCC) instead. We investigate the behavior of these models, including the expected size of the GCC for a given generation, the critical percolation probability, and other topological properties of the resulting graph structures using the analytically exact method of generating functions. We explore this model for Erdos-Renyi and scale-free random graphs. This model can be interpreted as a seasonal N-strain model of disease spreading.

Factors associated with intention to receive vaccines for bacterial sexually transmitted infections among young HPV-vaccinated Canadian women.

OBJECTIVE: The aim of this study was to explore the acceptability of bacterial STI vaccines among young HPV-vaccinated Canadian women to inform future vaccine program implementation. METHODS: A 20-item cross-sectional questionnaire was administered from June 2019 to June 2020 to HPV-vaccinated participants of the pan-Canadian QUEST cohort. Multivariable logistic regression models assessed interest in chlamydia, syphilis, and gonorrhea vaccines using a priori variables and factors significant in bivariate analysis. RESULTS: Of the 1092 respondents analyzed, 82% indicated interest in receiving one or more future STI vaccines. Respondents had a median age of 19.6 years (range 16.9-23.4), and 75% of respondents identified as white/European descent. In adjusted analyses, intent to engage in positive health behaviours was associated with vaccine interest for syphilis (OR = 5.76, 95% CI 4.03-8.27), chlamydia (OR = 5.27, 95% CI 3.66-7.63), and gonorrhea (OR = 5.96, 95% CI 4.15-8.60). Willingness to pay for an STI vaccine was also associated with vaccine interest for syphilis (OR = 2.02, 95% CI 1.29-3.19), chlamydia (OR = 2.41, 95% CI 1.50-3.90), and gonorrhea (OR = 2.29, 95% CI 1.44-3.63). Ever having sexual intercourse and identifying as LGBTQ were significantly associated with vaccine interest for all infections, while age and ever being immunosuppressed were not significant in any adjusted models. CONCLUSION: Findings indicate over 80% of participants in a cohort of young HPV-vaccinated Canadian women are interested in receiving future bacterial STI vaccines. Further exploration of STI vaccine acceptability among diverse populations is required to inform future bacterial STI vaccine program implementation.

RéSUMé: OBJECTIF: Cette étude visait à explorer l'acceptabilité des vaccins contre les ITS bactériennes chez les jeunes Canadiennes vaccinées contre le VPH pour éclairer la mise en œuvre de futurs programmes de vaccination. MéTHODE: Un questionnaire transversal de 20 questions a été administré entre juin 2019 et juin 2020 aux participantes de la cohorte QUEST pancanadienne ayant été vaccinées contre le VPH. Des modèles de régression logistique multivariée ont permis d'analyser l'intérêt pour les vaccins contre la chlamydia, la syphilis et la gonorrhée à l'aide de variables a priori et des facteurs significatifs dans l'analyse bivariée. RéSULTATS: Sur les 1 092 répondantes analysées, 82 % ont manifesté l'intérêt de recevoir un ou plusieurs futurs vaccins contre les ITS. L'âge médian des répondantes était de 19,6 ans (intervalle 16,9­23,4), et 75 % s'identifiaient comme étant blanches/d'ascendance européenne. Dans les analyses ajustées, l'intention de s'adonner à des comportements de santé positifs était associée à l'intérêt pour les vaccins contre la syphilis (RC = 5,76, IC de 95 % 4,03­8,27), la chlamydia (RC = 5,27, IC de 95 % 3,66­7,63) et la gonorrhée (RC = 5,96, IC de 95 % 4,15­8,60). La volonté de payer pour un vaccin contre les ITS était aussi associée à l'intérêt pour les vaccins contre la syphilis (RC = 2,02, IC de 95 % 1,29­3,19), la chlamydia (RC = 2,41, IC de 95 % 1,50­3,90) et la gonorrhée (RC = 2,29, IC de 95 % 1,44­3,63). Le fait d'avoir déjà eu des rapports sexuels et le fait de s'identifier comme une personne LGBTQ présentaient une corrélation significative avec l'intérêt pour les vaccins contre toutes les infections, mais l'âge et le fait d'avoir déjà subi un traitement immunodépresseur n'étaient des facteurs significatifs dans aucun des modèles ajustés. CONCLUSION: Selon nos constatations, plus de 80 % des participantes d'une cohorte de jeunes Canadiennes vaccinées contre les VPH sont intéressées à recevoir de futurs vaccins contre les ITS bactériennes. Une exploration plus poussée de l'acceptabilité des vaccins contre les ITS dans des populations à forte mixité est nécessaire pour éclairer la mise en œuvre de futurs programmes de vaccination contre les ITS bactériennes.

Optimizing Canadian public immunization programs: a prescription for action.

Recent expansion of public vaccination programs for children and youth offers new health benefits but at substantially increased cost. As with other large public investments, immunization programs ought to be systematically evaluated for safety, effectiveness and economic value. At present, program evaluations are suboptimal in most provinces and territories. Experts in public health and vaccinology who attended a workshop in 2009 reviewed the shortcomings and produced "prescriptions for action" to improve matters. Six key recommendations were made: 1) a formal requirement should exist to evaluate all public vaccination programs appropriately; 2) greater voluntary harmonization of programs will facilitate evaluations; 3) a mechanism is needed to prioritize and coordinate program-specific evaluations; 4) new funding mechanisms are needed for basic jurisdictional studies and joint studies of broad relevance; 5) strong emphasis is needed on capacity development and training; and 6) administrative barriers to accessing health information systems and publishing evaluation studies need to be overcome. The expert group considered the need to improve program evaluations as urgent and compelling, with success achievable with dedicated funding and effective leadership. Demonstrating that Canadian immunization programs are among the world's best and safest is a sound strategy for maintaining public participation in those programs.

Hepatitis C infection among pregnant women in British Columbia: reported prevalence and critical appraisal of current prenatal screening methods.

BACKGROUND: Despite the fact that hepatitis C virus (HCV) is a relatively common infection in Canada, particularly in British Columbia (BC), there is a paucity of information on actual HCV prevalence in pregnant women. At present, pregnant women are only screened if they fit risk criteria, which may result in under-identification of HCV in this population. The purpose of this study was to determine the overall prevalence rate, age and geographic distribution of reported HCV infection among pregnant women in BC, and compare results to a previously conducted anonymous seroprevalence survey. METHODS: Reported HCV prevalence was determined through a confidential database linkage of all prenatal screening results at the Canadian Blood Services (CBS) with all HCV test results at the Provincial Laboratory, from May 2000 to Oct 2002. Data were stratified by age group and geographic location, and subsequently compared to an anonymous prenatal seroprevalence survey conducted in 1994. RESULTS: The overall HCV prevalence rate was 50.3/10,000 (95% CI 46.3-54.6), or 0.5% of the cohort. Prevalence was highest in the northern BC region (66.2/10,000, 95% CI 51.4-85.3) and lowest in the populous suburban region southwest of Vancouver (38.0/10,000, 95% CI 32.3-44.8). Of note, the rate of reported HCV among pregnant women was significantly lower than the anonymous seroprevalence rate: 50.3/10,000 vs. 91.3/10,000 (p < 0.0001). CONCLUSION: Rates of reported HCV among pregnant women were approximately 50% lower than the rates determined by the anonymous seroprevalence survey. Further research is needed to determine the relative merits of the current selective screening policy versus universal prenatal HCV screening in pregnancy.