Antenatal tetanus, diphtheria, and acellular pertussis (Tdap) immunization and risk of serogroup 19 IPD in children: An indirect cohort study.

The tetanus-diphtheria-acellular pertussis (Tdap) vaccine has been indicated for pregnant women in Quebec, Canada since 2018. Recent literature suggests maternal Tdap interferes with the pneumococcal vaccine response in children exposed in utero because of maternally transferred anti-diphtheria antibodies, a phenomenon known as blunting. Using an indirect cohort study, we investigated whether maternal Tdap vaccination could alter the protection of PCV vaccines against serotype 19A/F IPD (conjugated to diphtheria toxoid in PCV10). Thirty-seven immunized IPD cases (serotype 19A/F) and 90 immunized IPD controls (non-vaccine serotypes) were analyzed using multivariate logistic regression. Our analyses did not identify antenatal Tdap exposure as a risk factor for IPD in vaccinated children, with and odds ratio close to the null (odds ratio = 0.82, 95%CI = 0.32-2.07). As this study is the first to assess the impact of maternal immunization on pneumococcal disease risk, future investigations involving a larger number of cases should be conducted to confirm or infirm our findings.

Comparison of Omicron breakthrough infection versus monovalent SARS-CoV-2 intramuscular booster reveals differences in mucosal and systemic humoral immunity.

Our understanding of the quality of cellular and humoral immunity conferred by COVID-19 vaccination alone versus vaccination plus SARS-CoV-2 breakthrough (BT) infection remains incomplete. While the current (2023) SARS-CoV-2 immune landscape of Canadians is complex, in late 2021 most Canadians had either just received a third dose of COVID-19 vaccine, or had received their two-dose primary series and then experienced an Omicron BT. Herein we took advantage of this coincident timing to contrast cellular and humoral immunity conferred by three doses of vaccine versus two doses plus BT. Our results show thatBT infection induces cell-mediated immune responses to variants comparable to an intramuscular vaccine booster dose. In contrast, BT subjects had higher salivary immunoglobulin (Ig)G and IgA levels against the Omicron spike and enhanced reactivity to the ancestral spike for the IgA isotype, which also reacted with SARS-CoV-1. Serumneutralizing antibody levels against the ancestral strain and the variants were also higher after BT infection. Our results support the need for the development of intranasal vaccines that could emulate the enhanced mucosal and humoral immunity induced by Omicron BT without exposing individuals to the risks associated with SARS-CoV-2 infection.

Multisystem inflammatory syndrome in 1.2 million children: longitudinal cohort study of risk factors.

BACKGROUND: We identified patient characteristics associated with an increased risk of developing MIS-C. METHODS: We conducted a longitudinal cohort study of 1,195,327 patients aged 0-19 years between 2006 and 2021, including the first two waves of the pandemic (February 25-August 22, 2020 and August 23, 2020-March 31, 2021). Exposures included prepandemic morbidity, birth outcomes, and family history of maternal disorders. Outcomes included MIS-C, Kawasaki disease, and other Covid-19 complications during the pandemic. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for the association between patient exposures and these outcomes using log-binomial regression models adjusted for potential confounders. RESULTS: Among 1,195,327 children, 84 developed MIS-C, 107 Kawasaki disease, and 330 other Covid-19 complications during the first year of the pandemic. Prepandemic hospitalizations for metabolic disorders (RR 11.3, 95% CI 5.61-22.6), atopic conditions (RR 3.34, 95% CI 1.60-6.97), and cancer (RR 8.11, 95% CI 1.13-58.3) were strongly associated with the risk of MIS-C, compared with no exposure. These same exposures were also associated with Kawasaki disease and other Covid-19 complications. However, birth characteristics and history of maternal morbidity were not associated with MIS-C development. CONCLUSIONS: Children with pre-existing morbidity have a considerably elevated risk of MIS-C. IMPACT: Morbidities that predispose children to multisystem inflammatory syndrome (MIS-C) are unclear. In this study, prepandemic hospitalizations for metabolic disorders, atopic conditions, and cancer were associated with an elevated risk of MIS-C. Birth characteristics and family history of maternal morbidity were not, however, associated with MIS-C. Pediatric morbidities may play a greater role in MIS-C onset than maternal or perinatal characteristics, and may help clinicians better recognize children at risk for this complication.

Clonal diversity of Streptococcus pneumoniae serotype 19A collected from children < 5 years old in Québec, Canada, 2016-2021.

Streptococcus pneumoniae serotype 19A is a highly diverse, often antimicrobial-resistant Gram-positive bacterium which can cause invasive pneumococcal disease (IPD). In 2021, public health authorities in the Canadian province of Québec observed an increase of serotype 19A IPD in children <5 years. The purpose of this study was to determine the clonal composition of serotype 19A isolates collected from this age group in Québec, from 2016 to 2021. Forty-one and 37 IPD isolates from children <5 years from Québec and the remainder of Canada, respectively, were sequenced using the Illumina NextSeq platform. Phylogenetic analysis using SNVPhyl identified three clusters, corresponding to three common clones of serotype 19A: CC199, CC320 and ST695. CC199, predominantly represented by ST416, accounted for similar proportions of serotype 19A isolates collected from children in Québec (19.5 %) and other Canadian jurisdictions (OCJs, 21.6 %), with significant presence of ermB (62.5 % and 60 % of ST416 isolates, respectively). CC320 was more commonly identified from OCJs in comparison to Québec (18.9 % vs. 7.3 %, respectively), but were highly antimicrobial-resistant regardless of region. ST695 was the most common clone of serotype 19A collected in Québec from children <5 years, representing 65.9 % of isolates collected over the study period (40.5 % of isolates collected in OCJs). Phylogenetic analysis identified geographical differences in ST695 across Canada; including a large clade specific to Québec (with both susceptible and macrolide-resistant [ermB] subclades), and a separate macrolide-resistant (mefA) clade associated with OCJs. The Québec-specific ermB-ST695 clone represented 48.1 % of ST695 collected from the province. Continued genomic surveillance of S. pneumoniae serotype 19A is required to: i) track the prevalence and clonal composition of serotype 19A in Québec in future years; ii) characterize the clonal distribution of serotype 19A in adult populations; and iii) monitor whether the currently geographically restricted ermB-ST695 clone observed in Québec expands to OCJs.

Sex differences in adverse events following seasonal influenza vaccines: a meta-analysis of randomised controlled trials.

BACKGROUND: Despite being a vaccine-preventable disease, influenza remains a major public health threat with vaccine safety concerns reducing vaccine acceptability. Immune responses to vaccines and adverse events may differ between males and females, but most studies do not report results by sex. Using data from clinical trials, we explored sex differences in adverse events following seasonal influenza vaccines. METHODS: We obtained data for phase III randomised controlled trials identified through a systematic review and clinical trials registries, and performed a two-stage meta-analysis. Risk ratios (RR) and 95% confidence intervals (95% CI) comparing solicited reactions in females versus males were pooled using the Mantel-Haenszel method and a random-effects model. We used the ROBINS-I tool to assess risk of bias and the I2 statistic for heterogeneity. Main analysis was stratified by age: 18-64 years and ≥65 years. RESULTS: The dataset for this analysis included 34 343 adults from 18 studies (12 with individual-level data and 6 with aggregate data). There was a higher risk of injection site reactions in females compared with males for both younger and older participants, with RRs of 1.29 (95% CI 1.21 to 1.37) and 1.43 (95% CI 1.28 to 1.60), respectively. Higher risk in females was also observed for systemic reactions, with RRs of 1.25 (95% CI 1.20 to 1.31) and 1.27 (95% CI 1.20 to 1.34) for younger and older participants, respectively. We also observed elevated risks of severe reactions in females, with a higher RR in younger versus older participants for systemic reactions (RRs 2.12 and 1.48, p=0.03, I2=79.7%). RRs were not found to vary between quadrivalent and trivalent vaccines. CONCLUSION: This meta-analysis suggested a higher risk of solicited reactions following influenza vaccines for females compared with males, irrespective of age and vaccine type. Transparent communication of this risk could increase the trust in vaccines and limit vaccine hesitancy. Future studies should report results stratified by sex and explore the role of gender in the occurrence of adverse events.

Canada's National Advisory Committee on immunization: Adaptations and challenges during the COVID-19 pandemic.

The COVID-19 pandemic has challenged traditional vaccine guidance infrastructure and frameworks, and added urgency and complexity to the operation of National Immunization Technical Advisory Groups (NITAGs). Canada's National Advisory Committee on Immunization (NACI) provides immunization guidance to the Public Health Agency of Canada (PHAC) who publicly shares expert and evidence-informed guidance with Canadian provinces and territories. Throughout the pandemic, NACI and PHAC implemented many adaptations to meet urgent needs for pandemic vaccine guidance. In this paper, we describe: structural adaptations in response to the accelerated pace and amount of work required to issue recommendations that were timed around product authorizations and dynamic epidemiology; technical adaptations in response to rapidly evolving evidence of variable quality which required close monitoring, and which promoted reliance on basic vaccine principles due to incomplete direct evidence; the need to provide nimble advice (e.g., off-label recommendations, preferential recommendations); communications adaptations (e.g. identify sustainable spokespeople for the committee, receive stakeholder feedback, and ensure urgent nuanced advice was communicated to a diverse audience); and research adaptations focussing on solutions to constrained supply (e.g. prioritisation, extended intervals, and heterologous schedules). The early pandemic vaccine experience has created a roadmap of lessons and adaptations that should be leveraged in future pandemic vaccine programs, and has highlighted the essential role of NITAGs to complement regulatory structures during pandemics to ensure timely, impactful, and evidence-informed public health vaccine guidance.

Infection-induced seroconversion and seroprevalence of SARS-CoV-2 among a cohort of children and youth in Montreal, Canada.

The EnCORE study is a prospective serology study of SARS-CoV-2 in a cohort of children from Montreal, Canada. Based on data from our fourth round of data collection (May-October 2022), we estimated SARS-CoV-2 seroprevalence and seroconversion. Using multivariable regression, we identified factors associated with seroconversion. Our results show that previously seronegative children were approximately 9-12 times more likely to seroconvert during the early Omicron-dominant period compared to pre-Omicron rounds. Unlike the pre-Omicron rounds, the adjusted rate of seroconversion among 2- to 4-year-olds was higher than older age groups. As seen previously, higher seroconversion rates were associated with ethnic/racial minority status.

Effectiveness of thirteen-valent pneumococcal conjugate vaccine to prevent serotype 3 invasive pneumococcal disease in Quebec in children, Canada.

In the province of Quebec, Canada, a 2 + 1 dose pneumococcal conjugate vaccine (PCV) program for children was implemented in 2004. PCV7 was replaced by PCV10 in 2009, by PCV13 in 2011 and by PCV10 in 2018, without catch-up in all instances. The objective was to estimate PCV13 effectiveness to prevent serotype 3 invasive pneumococcal disease in children aged less than 5 years, using 2010-2018 mandatory notification and laboratory surveillance data, an indirect cohort design and multivariate logistic regression models. A total of 29 cases of serotype 3 and 290 non-vaccine serotype cases as controls were analysed. Overall vaccine effectiveness (≥1 dose) was estimated at 59% [-39% to 88%]. During the first year after the last dose effectivness was 88% [47% to 97%] whereas no protection was observed thereafter. There was no trend towards increased effectiveness with the number of doses. PCV13 protection against serotype 3 IPD seems to be short-lived.

Young Investigator Interview with CSCI Distinguished Scientist Awardee Dr. Caroline Quach-Thanh.

Dr. Caroline Quach-Thanh is a Professor in the Departments of Microbiology, Infectious Diseases and Immunology and of Pediatrics at University of Montreal. She is in charge of Infection Prevention and Control at CHU Sainte-Justine where she works as a pediatric infectious diseases specialist and medical microbiologist. Dr. Quach is a clinician-scientist and the Canada Research Chair, Tier 1 in Infection Prevention and Control. In 2022, Dr. Quach-Thanh received the Distinguished Scientist Award 2022 from the Canadian Society for Clinical Investigation. In the same year, she received a Women of Distinction Award-for public service-from the Women's Y Foundation. Dr. Quach-Thanh is the former president from the Association for Medical Microbiology and Infectious Diseases Canada (AMMI), a past Chair of the National Advisory Committee on Immunization (NACI) and is the current chair of the Quebec Immunization Committee. She was named Fellow of the Canadian Academy of Health Sciences and of the Society for Healthcare Epidemiology of America. Dr. QuachThanh was selected as one of the 2019 most Powerful Women in Canada. In 2021, she received the Order of Merit from Université de Montréal and was made Officière de l'Ordre national du Québec in 2022.

Perspectives on COVID-19 Vaccination and Vaccine Passports in a Diverse Urban Adolescent Population: A Youth Participatory Mixed Methods Study.

PURPOSE: Disparities in youth COVID-19 vaccine acceptance and uptake have been documented in several countries, yet few studies have explored the attitudes and perceptions underlying vaccine-related decision-making among adolescent populations with unique sociocultural, environmental, and/or structural contexts that may influence vaccine uptake. METHODS: This study used data from surveys and semistructured interviews collected between January and March 2022 as part of an ongoing community-based research project in two ethnoculturally diverse, lower income neighborhoods of Montreal, Canada. Youth researchers designed and conducted interviews with unvaccinated adolescents, and thematic analysis was employed to explore attitudes and perceptions underlying vaccine-related decisions and opinions about vaccine passports. Survey data were used to describe sociodemographic and psychological determinants of COVID-19 vaccination. RESULTS: Among 315 survey participants aged 14-17 years, most (74%) were fully vaccinated against COVID-19. Prevalence ranged from 57% among Black adolescents to 91% among South and/or Southeast Asian adolescents (34% difference, 95% confidence interval: 20-49). Qualitative and quantitative findings highlighted several misconceptions about the safety, effectiveness, and necessity of COVID-19 vaccines and adolescents' desire for trusted sources of information to address their concerns. Vaccine passports likely increased uptake, yet adolescents were strongly resistant to the policy, and for some, it may have fueled distrust of government and scientific institutions. DISCUSSION: Strategies that increase the trustworthiness of institutions and foster genuine partnership with underserved youth may improve vaccine confidence and help ensure an effective, proequity recovery from COVID-19.

Prevention of COVID-19 with oral vitamin D supplemental therapy in essential healthcare teams (PROTECT): protocol for a multicentre, triple-blind, randomised, placebo-controlled trial.

INTRODUCTION: In the COVID-19 pandemic, healthcare workers (HCWs) were at high risk of infection due to their exposure to COVID infections. HCWs were the backbone of our healthcare response to this pandemic; every HCW withdrawn or lost due to infection had a substantial impact on our capacity to deliver care. Primary prevention was a key approach to reduce infection. Vitamin D insufficiency is highly prevalent in Canadians and worldwide. Vitamin D supplementation has been shown to significantly decrease the risk of respiratory infections. Whether this risk reduction would apply to COVID-19 infections remained to be determined. This study aimed to determine the impact of high-dose vitamin D supplementation on incidence of laboratory-confirmed COVID-19 infection rate and severity in HCWs working in high COVID incidence areas. METHODS AND ANALYSIS: PROTECT was a triple-blind, placebo-controlled, parallel-group multicentre trial of vitamin D supplementation in HCWs. Participants were randomly allocated in a 1:1 ratio in variable block size to intervention (one oral loading dose of 100 000 IU vitamin D3+10 000 IU weekly vitamin D3) or control (identical placebo loading dose+weekly placebo). The primary outcome was the incidence of laboratory-confirmed COVID-19 infection, documented by RT-qPCR on salivary (or nasopharyngeal) specimens obtained for screening or diagnostic purposes, as well as self-obtained salivary specimens and COVID-19 seroconversion at endpoint. Secondary outcomes included disease severity; duration of COVID-19-related symptoms; COVID-19 seroconversion documented at endpoint; duration of work absenteeism; duration of unemployment support; and adverse health events. The trial was terminated prematurely, due to recruitment difficulty. ETHICS AND DISSEMINATION: This study involves human participants and was approved by the Research Ethics Board (REB) of the Centre hospitalier universitaire (CHU) Sainte-Justine serving as central committee for participating institutions (#MP-21-2021-3044). Participants provided written informed consent to participate in the study before taking part. Results are being disseminated to the medical community via national/international conferences and publications in peer-reviewed journals. TRIAL REGISTRATION NUMBER: https://clinicaltrials.gov/ct2/show/NCT04483635.

Serratia marcescens Colonization in a Neonatal Intensive Care Unit Has Multiple Sources, with Sink Drains as a Major Reservoir.

Compelling evidence suggests a contribution of the sink environment to the transmission of opportunistic pathogens from the hospital environment to patients in neonatal intensive care units (NICU). In this study, the distribution of the opportunistic pathogen Serratia marcescens in the sink environment and newborns in a NICU was investigated. More than 500 sink drain and faucet samples were collected over the course of five sampling campaigns undertaken over 3 years. Distribution and diversity of S. marcescens were examined with a modified MacConkey medium and a high-throughput short-sequence typing (HiSST) method. Sink drains were an important reservoir of S. marcescens, with an average of 44% positive samples, whereas no faucet sample was positive. The genotypic diversity of S. marcescens was moderate, with an average of two genotypes per drain, while the spatial distribution of S. marcescens was heterogeneous. The genotypic profiles of 52 clinical isolates were highly heterogeneous, with 27 unique genotypes, of which 71% of isolates were found in more than one patient. S. marcescens acquisition during the first outbreaks was mainly caused by horizontal transmissions. HiSST analyses revealed 10 potential cases of patient-to-patient transmission of S. marcescens, five cases of patient-to-sink transmission, and one bidirectional transfer between sink and patient. Environmental and clinical isolates were found in sink drains up to 1 year after the first detection, supporting persisting drain colonization. This extensive survey suggests multiple reservoirs of S. marcescens within the NICU, including patients and sink drains, but other external sources should also be considered. IMPORTANCE The bacterium Serratia marcescens is an important opportunistic human pathogen that thrives in many environments, can become multidrug resistant, and is often involved in nosocomial outbreaks in neonatal intensive care units (NICU). We evaluated the role of sinks during five suspected S. marcescens outbreaks in a NICU. An innovative approach combining molecular and culture methods was used to maximize the detection and typing of S. marcescens in the sink environment. Our results indicate multiple reservoirs of S. marcescens within the NICU, including patients, sink drains, and external sources. These results highlight the importance of sinks as a major reservoir of S. marcescens and potential sources of future outbreaks.

Pre-Omicron seroprevalence, seroconversion, and seroreversion of infection-induced SARS-CoV-2 antibodies among a cohort of children and teenagers in Montréal, Canada.

OBJECTIVES: To use serological testing to assess the pre-Omicron seroprevalence, seroconversion, and seroreversion of infection-induced SARS-CoV-2 antibodies in children and adolescents in Montréal, Canada. DESIGN: This analysis is from a prospective cohort study of children aged 2-17 years (at baseline) that included blood spots for antibody detection. The serostatus of participants was determined by enzyme-linked immunosorbent assays using the receptor-binding domain from the spike protein and the nucleocapsid protein as antigens. We estimated seroprevalence, seroconversion rates, and the likelihood of seroreversion at 6 months and 1 year. RESULTS: The baseline (October 2020 to April 2021) seroprevalence was 5.8% (95% confidence interval [CI] 4.8-7.1), which increased to 10.5% (May to September 2021) and 11.0% (November 2021 to March 2022) for the respective follow-ups (95% CI 8.6-12.7; 95% CI 8.8-13.5). The crude rate of seroconversion over the study period was 12.8 per 100 person-years (95% CI 11.0-14.7). The adjusted hazard rates of seroconversion by child characteristics showed higher rates in children who were female, whose parent identified as a racial or ethnic minority, and in households with incomes in the lowest tercile of our study population. The likelihood of remaining seropositive at 6 months was 68% (95% CI 60-77%) and dropped to 42% (95% CI 32-56%) at 1 year. CONCLUSION: Serological studies continue to provide valuable contributions for infection prevalence estimates and help us better understand the dynamics of antibody levels after infection.

Increase of invasive pneumococcal disease in children temporally associated with RSV outbreak in Quebec: a time-series analysis.

Background: Respiratory viruses have been previously suspected to trigger invasive pneumococcal disease (IPD). After progressive non-pharmaceutical interventions (NPI) lifting, an unusual RSV outbreak has been observed in the Fall 2021, raising concerns about the possible consequences on IPD. We aimed to analyse the evolution of IPD incidence across age-groups since NPI lifting, and its temporal association with respiratory viral infections. Methods: We conducted a time-series analysis using 1) population-based IPD surveillance data and 2) statistics from the laboratory surveillance network of respiratory viruses in the province of Quebec, Canada, from January 2013 to January 2022. The monthly IPD incidence was analysed by quasi-Poisson regression models across age-groups. The fraction of IPD incidence change potentially attributable to different viruses in 2021-2022 was estimated. Findings: A total of 7712 IPD cases were included. After a major decrease in IPD incidence from April 2020, IPD rate started to increase in <5-year-old children in October 2021, exceeding the pre-NPI trend (+62%). This was temporally associated with an unusual surge in RSV cases (+53% versus pre-NPI trend). During this 2021-22 surge, the fraction of IPD attributable to RSV dynamics in children was 77% (95% CI [33-100]). By contrast, the IPD incidence in older age-groups remained low, and was temporally associated with influenza dynamics. Interpretation: These results provide new evidence on the role of respiratory viruses in driving IPD dynamics, with possible differences between children and adults. In the coming future, the potential benefit of interventions targeting RSV, such as vaccines, for IPD prevention should be considered. Funding: The study was supported by a grant from the Quebec Ministry of Health and Social Services ('ministère de la Santé et des Services sociaux du Québec'). Publication was supported by a grant from "Fondation de l'Assistance Publique - Hôpitaux de Paris et de l'Alliance « Tous Unis contre le Virus ¼ (Fondation de France/Institut Pasteur/APHP)". N.O. was supported by the ESPID (European Society of Pediatric Infectious Diseases) 2021-2023 Fellowship Award and the 2022 ISPPD (International Symposium on Pneumococci and Pneumococcal Diseases) Robert Austrian Research award.

SHEA Neonatal Intensive Care Unit (NICU) White Paper Series: Practical approaches for the prevention of central-line-associated bloodstream infections.

This document is part of the "SHEA Neonatal Intensive Care Unit (NICU) White Paper Series." It is intended to provide practical, expert opinion, and/or evidence-based answers to frequently asked questions about CLABSI detection and prevention in the NICU. This document serves as a companion to the CDC Healthcare Infection Control Practices Advisory Committee (HICPAC) Guideline for Prevention of Infections in Neonatal Intensive Care Unit Patients. Central line-associated bloodstream infections (CLABSIs) are among the most frequent invasive infections among infants in the NICU and contribute to substantial morbidity and mortality. Infants who survive CLABSIs have prolonged hospitalization resulting in increased healthcare costs and suffer greater comorbidities including worse neurodevelopmental and growth outcomes. A bundled approach to central line care practices in the NICU has reduced CLABSI rates, but challenges remain. This document was authored by pediatric infectious diseases specialists, neonatologists, advanced practice nurse practitioners, infection preventionists, members of the HICPAC guideline-writing panel, and members of the SHEA Pediatric Leadership Council. For the selected topic areas, the authors provide practical approaches in question-and-answer format, with answers based on consensus expert opinion within the context of the literature search conducted for the companion HICPAC document and supplemented by other published information retrieved by the authors. Two documents in the series precede this one: "Practical approaches to Clostridioides difficile prevention" published in August 2018 and "Practical approaches to Staphylococcus aureus prevention," published in September 2020.

Impact of Covid-19 on rates of gestational diabetes in a North American pandemic epicenter.

AIMS: We assessed the impact of Covid-19 on gestational diabetes rates in Quebec, the pandemic epicenter of Canada. METHODS: We conducted a population-based study of 569,686 deliveries in Quebec between 2014 and 2021. We measured gestational diabetes rates in wave 1 (March 1, 2020-August 22, 2020) and wave 2 (August 23, 2020-March 31, 2021), compared with the prepandemic period. We used interrupted time series regression to assess changes in gestational diabetes rates during each wave, and log-binomial regression models to estimate adjusted risk ratios (RR) and 95% confidence intervals (CI) for the association of the pandemic with gestational diabetes. We identified the types of patients that contributed to the change in gestational diabetes rates using Kitagawa's decomposition. RESULTS: Gestational diabetes rates were higher during the first (13.2 per 100 deliveries) and second waves (14.3 per 100 deliveries) than during the prepandemic period (12.4 per 100 deliveries). Risk of gestational diabetes increased both in wave 1 (RR 1.05, 95% CI 1.02-1.09) and wave 2 (RR 1.14, 95% CI 1.10-1.18), compared with the prepandemic period. However, most of the increase in gestational diabetes rates was driven by low-risk women without Covid-19 infections who were socioeconomically advantaged, had no comorbidity, and were 25-34 years of age. CONCLUSIONS: Gestational diabetes rates increased during the pandemic, mainly among women traditionally at low risk of hyperglycemia who did not have Covid-19 infections. Sudden widespread changes in screening or lifestyle can have a large impact on gestational diabetes rates in a population.

Mitigating healthcare staffing shortages: Should healthcare workers with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) household exposures work?

In a tertiary-care, pediatric healthcare center in Québec, Canada, healthcare workers who reported a household exposure to confirmed coronavirus disease 2019 (COVID-19) cases were allowed to work. On repeated testing, 15% became severe acute respiratory coronavirus virus 2 (SARS-CoV-2)-positive by reverse-transcription polymerase chain reaction (RT-PCR), with no nosocomial transmission. Being asymptomatic and receiving a booster dose >7 days prior to exposure was protective against becoming SARS-CoV-2-positive by PCR.

High-Throughput Short Sequence Typing Schemes for Pseudomonas aeruginosa and Stenotrophomonas maltophilia Pure Culture and Environmental DNA.

Molecular typing techniques are utilized to determine genetic similarities between bacterial isolates. However, the use of environmental DNA profiling to assess epidemiologic links between patients and their environment has not been fully explored. This work reports the development and validation of two high-throughput short sequence typing (HiSST) schemes targeting the opportunistic pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia, along with a modified SM2I selective medium for the specific isolation of S. maltophilia. These HiSST schemes are based on four discriminative loci for each species and demonstrate high discriminating power, comparable to pairwise whole-genome comparisons. Each scheme includes species-specific PCR primers for precise differentiation from closely related taxa, without the need for upstream culture-dependent methods. For example, the primers targeting the bvgS locus make it possible to distinguish P. aeruginosa from the very closely related Pseudomonas paraeruginosa sp. nov. The selected loci included in the schemes are adapted to massive parallel amplicon sequencing technology. An R-based script implemented in the DADA2 pipeline was assembled to facilitate HiSST analyses for efficient and accurate genotyping of P. aeruginosa and S. maltophilia. We demonstrate the performance of both schemes through in silico validations, assessments against reference culture collections, and a case study involving environmental samples.