The persistence of seroprotective levels of antibodies after vaccination with PreHevbrio, a 3-antigen hepatitis B vaccine.

Prevention of hepatitis B virus (HBV) infection by vaccination can potentially eliminate HBV-related diseases. PreHevbrio™/PreHevbri® is a 3-antigen (S, preS1, preS2) HBV vaccine (3A-HBV) recently licensed for adults in the US, EU and Canada. This study evaluated antibody persistence in a subset of fully vaccinated and seroprotected (anti-HBs ≥ 10 mIU/mL) Finnish participants from the phase 3 trial (PROTECT) of 3A-HBV versus single-antigen HBV vaccine (1A-HBV). 465/528 eligible subjects were enrolled (3A-HBV: 244; 1A-HBV: 221). Baseline characteristics were balanced. After 2.5 years, more 3A-HBV subjects remained seroprotected (88.1 % [95 %CI: 84.1,92.2]) versus 1A-HBV (72.4 % [95 %CI: 66.6,78.3)], p < 0.0001) and had higher mean anti-HBs [1382.9 mIU/mL (95 %CI: 1013.8,1751.9) versus 252.6 mIU/mL (95 %CI: 127.5,377.6), p < 0.0001]. In multiple variable logistic regression analysis including age, vaccine, initial vaccine response, sex and BMI, only higher post dose 3 (Day 196) antibody titers significantly reduced the odds of losing seroprotection.

Kinetics of the antibody response to tetanus-diphtheria-acellular pertussis vaccine in women of childbearing age and postpartum women.

BACKGROUND: Because adolescents and adults act as a primary source of pertussis infection for infants, vaccination of mothers immediately postpartum is a potential strategy to reduce transmission (cocoon strategy). For this to be effective, high levels of antibodies must be achieved rapidly after vaccination. We sought to determine whether the antibody response to tetanus-diphtheria-acellular pertussis vaccine (Tdap) is sufficiently rapid to support the cocoon strategy. METHODS: Two sequential studies were performed. The first was a nonrandomized, open study of a 5-pertussis-component Tdap vaccine (tetanus toxoid, diphtheria toxoid, pertussis toxoid [PT], filamentous hemagglutinin [FHA], fimbriae types 2 and 3 [FIM], and pertactin [PRN]) given to women of childbearing age; the second was a randomized, open study of Tdap or no vaccine in postpartum women. Serum levels of immunoglobin (Ig) G and IgA against pertussis antigens, serum levels of IgG against diphtheria and tetanus, and breast milk levels of IgA against pertussis antigens were measured at various times after vaccination. RESULTS: In both studies, the antibody response was relatively rapid, with serum IgG and IgA levels beginning to increase noticeably by days 5-7 and approaching peak levels by day 14. Greater than 68% and 84.4% of IgG and IgA responders, respectively, achieved ≥ 90% of their maximum titer by day 14. The diphtheria and tetanus antibody kinetics followed a similar time course. Breast milk levels of IgA against PT, FHA, and FIM were first detectable at day 7, peaked by day 10, and then slowly decreased through day 28. Antibodies against PRN showed a similar response, although the peak occurred at day 14. There were no significant antibody responses in the control group. CONCLUSIONS: Although the antibody response to a dose of Tdap in healthy nonpregnant women of child-bearing age and postpartum women occurs by day 14 and is suggestive of an anamnestic immune response, it may not be sufficiently rapid to protect infants in the first weeks of life.

Validation of the Seegene RV15 multiplex PCR for the detection of influenza A subtypes and influenza B lineages during national influenza surveillance in hospitalized adults.

Background. The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network (CIRN SOS) has been performing active influenza surveillance since 2009 (ClinicalTrials.gov identifier: NCT01517191). Influenza A and B viruses are identified and characterized using real-time reverse-transcriptase polymerase chain reaction (RT-PCR), and multiplex testing has been performed on a subset of patients to identify other respiratory virus aetiologies. Since both methods can identify influenza A and B, a direct comparison was performed.Methods. Validated real-time RT-PCRs from the World Health Organization (WHO) to identify influenza A and B viruses, characterize influenza A viruses into the H1N1 or H3N2 subtypes and describe influenza B viruses belonging to the Yamagata or Victoria lineages. In a subset of patients, the Seeplex RV15 One-Step ACE Detection assay (RV15) kit was also used for the detection of other respiratory viruses.Results. In total, 1111 nasopharyngeal swabs were tested by RV15 and real-time RT-PCRs for influenza A and B identification and characterization. For influenza A, RV15 showed 98.0 % sensitivity, 100 % specificity and 99.7 % accuracy. The performance characteristics of RV15 were similar for influenza A subtypes H1N1 and H3N2. For influenza B, RV15 had 99.2 % sensitivity, 100 % specificity and 99.8 % accuracy, with similar assay performance being shown for both the Yamagata and Victoria lineages.Conclusions. Overall, the detection of circulating subtypes of influenza A and lineages of influenza B by RV15 was similar to detection by real-time RT-PCR. Multiplex testing with RV15 allows for a more comprehensive respiratory virus surveillance in hospitalized adults, without significantly compromising the reliability of influenza A or B virus detection.

Motivation for participating in phase 1 vaccine trials: Comparison of an influenza and an Ebola randomized controlled trial.

INTRODUCTION/HYPOTHESIS: Recruitment of participants into phase 1 vaccine clinical trials can be challenging since these vaccines have not been used in humans and there is no perceived benefit to the participant. Occasionally, as was the case with a phase 1 clinical trial of an Ebola vaccine in Halifax, Canada, during the 2014-2016 West African Ebola virus outbreak, recruitment is less difficult. In this study, we explored the motivations of participants in two phase 1 vaccine trials that were concurrently enrolling at the same centre and compared the motivations of participants in a high-profile phase 1 Ebola vaccine trial to those in a less high-profile phase 1 adjuvanted seasonal influenza vaccine study. METHODS: An online survey which included participants' prior experience with clinical trials, motivations to participate (including financial incentives), and demographic information was developed to examine the motivations of healthy participants in two phase 1 clinical vaccine trials conducted at the Canadian Center for Vaccinology in Halifax, Nova Scotia. Participants were invited via email to complete the online survey. Readability and clarity were assessed through pilot testing. RESULTS: A total of 49 (55.7%) of 88 participants of the two studies completed the survey (22 [55%] of 40 participants from the Ebola vaccine study and 27 [56.3%] of 48 from the adjuvanted influenza vaccine study). Motivations that were most frequently ranked among participants' top three in both trials were (1) wanting to contribute to the health of others, (2) wanting to participate in something important, (3) wanting to contribute to the advancement of science, and (4) wanting to receive an incentive such as money or a tablet. CONCLUSIONS/RECOMMENDATIONS: Although media attention and financial compensation were more often cited by Ebola vaccine trial participants as a reason to participate, both altruistic and self-interested factors were important motivations for participants in their decision to participate in a phase 1 vaccine clinical trial.

Knowledge, attitudes, beliefs, and behaviors of university students, faculty, and staff during a meningococcal serogroup B outbreak vaccination program.

OBJECTIVES: During an outbreak of invasive meningococcal B disease on a university campus, we explored the knowledge, attitudes, beliefs, and behaviors of members of the university community in relation to the disease, the vaccine, and the vaccination program. DESIGN: All students, faculty and staff were invited by email to participate in a 71-item online survey, which was administered after completion of the mass clinics for the first and second doses of a meningococcal B vaccination program. RESULTS: A total of 404 individuals responded to the survey; 75.7% were students. Knowledge about meningococcal disease and vaccine was generally high; more than 70% correct responses were received on each knowledge question except for one question about the different meningococcal serogroups. Gender (female) and higher knowledge scores were significantly associated with either being immunized or intending to be immunized (p<0.05). Positive attitudes about immunization, concern about meningococccal infection, a sense of community responsibility, and trust in public health advice also correlated with being vaccinated or intending to be vaccinated (p<0.05). CONCLUSIONS: A successful mass vaccination program in a Nova Scotia university was associated with high levels of knowledge, positive attitudes toward vaccination, and positive attitudes toward public health recommendations.

Routine immunization of adults by pharmacists: Attitudes and beliefs of the Canadian public and health care providers.

Vaccine coverage among adults for recommended vaccines is generally low. In Canada and the US, pharmacists are increasingly becoming involved in the administration of vaccines to adults. This study measured the knowledge, attitudes, beliefs, and behaviors of Canadian adults and health care providers regarding pharmacists as immunizers. Geographically representative samples of Canadian adults (n = 4023) and health care providers (n = 1167) were surveyed, and 8 focus groups each were conducted nationwide with adults and health care providers. Provision of vaccines by pharmacists was supported by 64.6% of the public, 82.3% of pharmacists, 57.4% of nurses, and 38.9% of physicians; 45.7% of physicians opposed pharmacist-delivered vaccination. Pharmacists were considered a trusted source of vaccination information by 75.0% of the public, exceeding public health officials (68.3%) and exceeded only by doctors and nurses (89.2%). Public concerns about vaccination in pharmacies centered on safety (management of adverse events), record keeping (ensuring their family physician was informed), and cost (should be no more expensive than vaccination at public health or physicians' offices). Concerns about the logistics of vaccination delivery were expressed more frequently in regions where pharmacists were not yet immunizing than in jurisdictions with existing pharmacist vaccination programs. These results suggest that the expansion of pharmacists' scope of practice to include delivery of adult vaccinations is generally accepted by Canadian health care providers and the public. Acceptance of this expanded scope of pharmacist practice may contribute to improvements in vaccine coverage rates by improving vaccine accessibility.

Rapid surveillance for health events following a mass meningococcal B vaccine program in a university setting: A Canadian Immunization Research Network study.

An outbreak of Neisseria meningitidis serotype B infection occurred at a small residential university; public health announced an organizational vaccination program with the 4-component Meningococcal B (4CMenB) vaccine (Bexsero(TM), Novartis/GlaxoSmithKline Inc.) several days later. Since there were limited published data on reactogenicity of 4CMenB in persons over 17years of age, this study sought to conduct rapid surveillance of health events in vaccinees and controls using an online survey. Vaccine uptake was 84.7% for dose 1 (2967/3500) and 70% (2456/3500) for dose 2; the survey response rates were 33.0% (987/2967) and 18.7% (459/2456) in dose 1 and dose 1 recipients respectively, and 12% in unvaccinated individuals (63/533). Most students were 20-29years of age (vaccinees, 64.0%; controls, 74.0). A new health problem or worsening of an existing health problem was reported by 30.0% and 30.3% of vaccine recipients after doses 1 and 2 respectively; and by 15.9% of controls. These health problems interfered with the ability to perform normal activities in most vaccinees reporting these events (74.7% post dose 1; 62.6% post dose 2), and in 60% of controls. The health problems led to a health care provider visit (including emergency room) in 12.8% and 14.4% of vaccinees post doses 1 and 2, respectively and in 40% of controls. The most common reactions in vaccinees were injection site reactions (20.6% post dose 1, 16.1% post dose 20 and non-specific systemic complaints (22.6% post dose 1, 17.6% post dose 2). No hospitalizations were reported. An online surveillance program during an emergency meningococcal B vaccine program was successfully implemented, and detected higher rates of health events in vaccinees compared to controls, and high rates of both vaccinees and controls seeking medical attention. The types of adverse events reported by young adult vaccinees were consistent with those previously.

The challenge of vaccinating adults: attitudes and beliefs of the Canadian public and healthcare providers.

OBJECTIVES: Vaccine coverage for recommended vaccines is low among adults. The objective of this study was to assess the knowledge, attitudes, beliefs and behaviours of adults and healthcare providers related to four vaccine-preventable diseases and vaccines (diphtheria-tetanus-pertussis, zoster, pneumococcus and influenza). DESIGN: We undertook a survey and focus groups of Canadian adults and healthcare providers (doctors, nurses, pharmacists). A total of 4023 adults completed the survey and 62 participated in the focus groups; 1167 providers completed the survey and 45 participated in the focus groups. RESULTS: Only 46.3% of adults thought they were up-to-date on their vaccines; 30% did not know. In contrast, 75.6% of providers reported being up-to-date. Only 57.5% of adults thought it was important to receive all recommended vaccines (compared to 87.1-91.5% of providers). Positive attitudes towards vaccines paralleled concern about the burden of illness and confidence in the vaccines, with providers being more aware of disease burden and confident in vaccine effectiveness than the public. Between 55.0% and 59.7% of adults reported willingness to be vaccinated if recommended by their healthcare provider. However, such recommendations were variable; while 77.4% of the public reported being offered and 52.8% reported being recommended the influenza vaccine by their provider, only 10.8% were offered and 5.6% recommended pertussis vaccine. Barriers and facilitators to improved vaccine coverage in adults, such as trust-mistrust of health authorities, pharmaceutical companies and national recommendations, autonomy versus the public good and logistical issues (such as insufficient time and lack of vaccination status tracking), were identified by both the public and providers. CONCLUSIONS: Despite guidelines for adult vaccination, there are substantial gaps in knowledge and attitudes and beliefs among both the public and healthcare providers that lead to low vaccine coverage. A systematic approach that involves education, elimination of barriers and establishing and improving infrastructure for adult immunisation is required.

Universal tetanus, diphtheria, acellular pertussis (Tdap) vaccination of adults: What the Canadian public knows and wants to know.

Tetanus, diphtheria, and acellular pertussis vaccine (Tdap) is recommended for all adults in Canada but uptake is low. This study measured the knowledge, attitudes, beliefs, and behaviors of Canadian adults to identify potential barriers and facilitators to Tdap uptake. A survey was undertaken on a geographically representative sample of Canadian adults (n=4023) and 8 focus groups (62 participants) were conducted nationwide. The survey revealed that knowledge about pertussis and Tdap was low (38.3% correct answers). Only 36.0% of respondents reported being aware that all adults were recommended to receive Tdap and only 10.7% reported being immunized; 36.7% did not know whether they had received Tdap. Respondents who were aware of the immunization recommendations were twice as likely to be immunized (16.6% vs. 8.3%; p<0.001). Only 9.3% believed that their health care provider thought that Tdap was important for adults. The focus group data supported the survey results. Participants wanted information about pertussis and Tdap communicated through multiple modalities, but a recommendation by their family physician was most important to their decision to be immunized or not. This study demonstrates that current recommendations for universal adult vaccination with Tdap are not reaching the general public in Canada and an alternative strategy will be required to improve Tdap vaccine uptake.

Universal tetanus, diphtheria, acellular pertussis (Tdap) vaccination of adults: What Canadian health care providers know and need to know.

The tetanus, diphtheria, and acellular pertussis vaccine (Tdap) is recommended for all adults in both Canada and the United States. There are few data on the proportion of Canadian adults vaccinated with Tdap; however, anecdotal reports indicate that uptake is low. This study aimed to explore the knowledge, attitudes, beliefs, and behaviors of Canadian health care providers (HCPs) in an attempt to identify potential barriers and facilitators to Tdap uptake. HCPs were surveyed and a geographic and practice representative sample was obtained (N =1,167). In addition, 8 focus groups and 4 interviews were conducted nationwide. Results from the survey indicate that less than half (47.5%) of all respondents reported being immunized with Tdap themselves, while 58.5% routinely offer Tdap to their adult patients. Knowledge scores were relatively low (63.2% correct answers). The best predictor of following the adult Tdap immunization guidelines was awareness of and agreement with those recommendations. Respondents who were aware of the recommendations were more likely to think that Tdap is safe and effective, that their patients are at significant risk of getting pertussis, and to feel that they have sufficient information (p < 0.0001 for each statement). Focus group data supported the survey results and indicated that there are substantial gaps in knowledge of pertussis and Tdap among Canadian HCPs. Lack of public knowledge about adult immunization, lack of immunization registries, a costing differential between Td and Tdap, workload required to deliver the vaccine, and vaccine hesitancy were identified as barriers to compliance with the national recommendations for universal adult immunization, and suggestions were provided to better translate recommendations to front-line practitioners.

Canadian vaccine research networks: Vaccine safety resources for Canada.

The Public Health Agency of Canada / Canadian Institutes of Health Research Influenza Research Network (PCIRN), established in 2009 to undertake evaluative research to inform public health decision making in Canada, is now being replaced by the Canadian Immunization Research Network (CIRN), which will retain the mandate of PCIRN but expand it to all vaccines including influenza vaccine. CIRN is organized as a network of networks focusing on undertaking research in the areas of vaccine safety, adverse events following immunization (AEFIs), vaccine hesitancy, vaccine effectiveness, and vaccine coverage. CIRN's networks include: a clinical trial network; a laboratory network; a modelling and economics network; a network of social science and humanities researchers; a vaccine safety surveillance network; a hospital-based surveillance network; a clinic network to evaluate serious AEFIs; and a network that links vaccine research capacity in provincial health agencies and departments. PCIRN has contributed to Canada's vaccine safety surveillance system and has facilitated the translation of safety research into policy. Vaccine safety surveillance and research will remain a focus of the newly formed Canadian Immunization Research Network.

Autosomal recessive inheritance of vasopressin-resistant diabetes insipidus.

We report on 2 intellectually normal sisters with vasopressin-resistant (nephrogenic) diabetes insipidus (NDI). The sex of the patients, the history of parental consanguinity, and the fact that both parents formed normally concentrated urine suggested that the NDI in the 2 sisters was the result of inheritance of an autosomal recessive mutation affecting renal tubular water reabsorption. The results of DNA analysis of the DXS52 locus with the use of St14 as probe, shown by Knoers et al. [1988] to be tightly linked to the NDI locus on the X-chromosome, showed that each girl inherited different Xq28 regions of the maternal X chromosomes, ruling out a diagnosis of classical X-linked NDI.

Canadian Acute Respiratory Illness and Flu Scale (CARIFS): development of a valid measure for childhood respiratory infections.

Although acute respiratory infection (ARI) is the most frequent clinical syndrome in childhood, there is no validated measure of its severity. Therefore a parental questionnaire was developed: the Canadian Acute Respiratory Illness Flu Scale (CARIFS). A process of item generation, item reduction, and scale construction resulted in a scale composed of 18 items covering three domains; symptoms (e.g., cough); function (e.g., play), and parental impact (e.g., clinginess). The validity of the scale was evaluated in a study of 220 children with ARI. Construct validity was assessed by comparing the CARIFS score with physician, nurse, and parental assessment of the child's health. Data were available from 206 children (94%). The CARIFS correlated well with measures of the construct (Spearman's correlations between 0.36 and 0.52). Responsiveness was shown, with 90% of children having a CARIFS score less than a quarter of its initial value, by the tenth day.

Epidemiologic study of 4684 hospital-acquired infections in pediatric patients.

During a 4-year period 4684 nosocomial infections occurred in a university pediatric hospital which admitted 78,120 patients (nosocomial infection rate (NIR) = 6.0). NIR varied from 0.17 to 14.0 on different wards or services; the highest rates (greater than or equal to 5.6) were found in the Neonatal Intensive Care Unit, infant neurosurgery, hematology/oncology, neonatal surgery, cardiology/cardiovascular surgery, Pediatric Intensive Care Unit and infant/toddler medicine areas. Infections were most common in patients less than or equal to 23 months (NIR = 11.5), were less common in the 2- to 4-year age group (NIR = 3.6) and occurred least frequently in patients greater than or equal to 5 years (NIR = 2.6). The median day of onset of infections was 15.3 days. The proportional frequencies of infections were: 35% gastrointestinal; 21% bacteremia; 16% respiratory (10% upper, 6% lower); 7% postoperative wound; 6% urinary tract; 5% skin (32% of these skin infections were related to intravascular lines); 5% eye; 3% cerebrospinal fluid; and 2% other. A similar proportional frequency of 379 infections in patients hospitalized for more than 100 days was observed. The etiologic agents were Gram-positive bacteria (50%), viruses (23%), Gram-negative bacteria (18%), fungi (4%) and mixed/other (5%).

Variable morbidity of respiratory syncytial virus infection in patients with underlying lung disease: a review of the PICNIC RSV database. Pediatric Investigators Collaborative Network on Infections in Canada.

OBJECTIVE: We wished to compare outcomes of respiratory syncytial virus (RSV) infection in children with bronchopulmonary dysplasia (BPD) with those with other pulmonary disorders: cystic fibrosis, recurrent aspiration pneumonitis, pulmonary malformation, neurogenic disorders interfering with pulmonary toilet, and tracheoesophageal fistula. METHODS: Children with RSV infection hospitalized at seven Canadian pediatric tertiary care hospitals in 1993 through 1994 and 9 hospitals in 1994 through 1995 were enrolled and prospectively followed. This study is a secondary analysis of data from this prospective cohort. RESULTS: Of the 1516 patients enrolled the outcomes of 159 with preexisting lung disorders before RSV lower respiratory tract infection constitute this report. There were no significant differences among the 7 groups (BPD, cystic fibrosis, recurrent aspiration pneumonitis, pulmonary malformation, neurogenic disorders interfering with pulmonary toilet, tracheoesophageal fistula, other) for the morbidity measures: duration of hospitalization, intensive care unit (ICU) admission, duration of ICU stay, mechanical ventilation and duration of mechanical ventilation. Patients using home oxygen were more likely to be admitted to the ICU than those who had never or previously used home oxygen (current 57.1%, past 23.8%, never 33.3%, P = 0.03). CONCLUSIONS: Children with other underlying diseases have morbidity similar to those with BPD. Prophylactic interventions against RSV should also be studied in these groups.

Evaluation of a tuberculosis screening program at a children's hospital.

Routine screening of patients for tuberculosis at the time of hospitalization and annual screening of hospital employees continue to be controversial. No data are available concerning tuberculosis screening programs at pediatric facilities. We reviewed the results of patient and employee tuberculosis screening programs in the last decade at the Izaak Walton Killam Hospital for Children. Four (11%) of 37 cases of tuberculosis were unsuspected until identified by the routine screening of all children at their admission to the hospital. No cases of tuberculosis were identified as a result of the employee screening program. Compliance with both screening programs was less than optimal. Review of programs at other Canadian pediatric centers demonstrated a range of practice. We conclude that routine screening of patients at the time of admission to the hospital and the annual screening of employees are unwarranted at present at our children's hospital. However, discontinuation of routine testing necessitates aggressive contact-tracing by public health authorities of patients with identified cases and periodic reevaluation of costs and benefits to determine whether reintroduction of screening is appropriate.

Unique epidemiology of nosocomial urinary tract infection in children.

BACKGROUND: Nosocomial urinary tract infection (NUTI) occurs with varying frequency in children and is thought to be associated with urethral instrumentation. In response to changing infection control resources at our facility, we reviewed NUTI to determine whether the frequency of NUTI, associated complications, or presence of a remediable risk factor (instrumentation) justified ongoing routine infection control surveillance. METHODS: Prospective surveillance was conducted on all wards 8 months per year from January 1991 through December 1997 by an infection control nurse coordinator. NUTI was defined by laboratory evidence according to Center for Disease Control and Prevention definitions and detected 48 hours after admission. Urinary catheterization in the previous 7 days was categorized as continuous/indwelling or intermittent. RESULTS: NUTI was the fifth most common nosocomial infection (129/1375; approximately 9%) and decreased in frequency during the decade from 0.9 to approximately 0.6 cases/1000 patient days. Incidence was equal among men and women. Only 50% of cases had prior instrumentation of the urinary tract. NUTI occurred disproportionately in newborns and infants (P <.001). The most common pathogen was Escherichia coli (28%; 38/132), followed by Candida sp (18%; 24/134), Enterococcus (13%; 18/134), gram-negative nonfermenters (13%; 17/132), Enterobacter (approximately 10%; 13/134), Pseudomonas (9.7%; 13/134), and other (16%; 22/134). Three cases of secondary bacteremia occurred (2.3%; 95% confidence interval 0.5-6.6); there was no mortality. CONCLUSIONS: NUTI poses a less significant burden of illness (incidence, associated morbidity) than other nosocomial infection in children. If resources do not permit hospital-wide surveillance, high-risk children with urethral instrumentation and newborns and infants could be targeted. Although E coli remains the most common cause of pediatric NUTI, fungi have become the second most common pathogen in this tertiary care population. Risk factors for NUTI in noncatheterized children remain to be delineated.

Demand for isolation beds in a pediatric hospital.

OBJECTIVE: To determine isolation bed use for community-acquired and nosocomial infections in a pediatric hospital. DESIGN: A prospective repeated point prevalence survey was conducted during a 14-month period. A questionnaire was sent to other free-standing Canadian children's hospitals to determine isolation practice and perceived needs. SETTING: A university-affiliated, 218-bed pediatric hospital in Halifax, Nova Scotia, Canada. PATIENTS: All inpatients on surveyed wards during the study period (n = 1634). RESULTS: Overall, 13.5% of patients required isolation (range 5.6% to 31% per month). Demand was seasonal, with 71% of isolation occurring from November to April. Demand exceeded supply by 2 to 22 beds (11% to 122%). Respiratory and enteric infections requiring contact isolation accounted for 80% of use (53% and 27%, respectively). Children younger than 24 months comprised 28% of admissions and used 57% of isolation beds. Of patients isolated, 25% had nosocomial infections and 75% had community-acquired infections. The percentage of infant rooms in Canadian children's hospitals that were single bed (considered optimal for infant isolation) varied: 0% to 20% for hospitals built before 1965 and 25% to 47% for newer hospitals. All hospitals with less than 33% single-bed infant rooms perceived this allocation to be inadequate (p < 0.01 Fisher Exact Test). CONCLUSIONS: Pediatric isolation bed use varies with patient age, season of year, and category-specific isolation requirements. An increasing need for single-bed rooms is identified. Isolation requirements must be considered during the design of new hospitals or renovation of existing ones.

Variation in risk for nosocomial chickenpox after inadvertent exposure.

Inadvertent exposure to chickenpox in the healthcare setting results in time-consuming and expensive infection control management strategies. In households, secondary cases occur in up to 96% of susceptibles, but transmission risk after exposure in an occupational setting is less well defined. In this prospective cohort study of inadvertent exposures in a 180-bed paediatric hospital, the secondary transmission rate was 4.5% (4/89; 95% confidence interval 1.2, 11.1%). Fourteen index cases exposed 158 patients and 93 healthcare workers over a 36-month study period. Exposures occurred in inpatient and ambulatory settings, with patients, staff and siblings serving as index cases. Transmission only occurred when the index case and contacts were in the same room and not in a multi-room setting (12% v. 0%, Fisher exact test, P = 0.02). Occupational exposures present a lesser transmission risk than those in households. Definition of those exposure variables that increase risk of transmission in the occupational setting should be explored in future studies.