The Effect of COVID-19 Vaccination on Outpatient Antibiotic Prescribing in Older Adults: A Self-Controlled Risk-Interval Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) vaccination has been associated with reduced outpatient antibiotic prescribing among older adults with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed the impact of COVID-19 vaccination on outpatient antibiotic prescribing in the broader population of older adults, regardless of SARS-CoV-2 infection status. METHODS: We included adults aged ≥65 years who received their first, second, and/or third COVID-19 vaccine dose from December 2020 to December 2022. We used a self-controlled risk-interval design and included cases who received an antibiotic prescription 2-6 weeks before vaccination (pre-vaccination or control interval) or after vaccination (post-vaccination or risk interval). We used conditional logistic regression to estimate the odds of being prescribed (1) any antibiotic, (2) a typical "respiratory" infection antibiotic, or (3) a typical "urinary tract" infection antibiotic (negative control) in the post-vaccination interval versus the pre-vaccination interval. We accounted for temporal changes in antibiotic prescribing using background monthly antibiotic prescribing counts. RESULTS: 469 923 vaccine doses met inclusion criteria. The odds of receiving any antibiotic or a respiratory antibiotic prescription were lower in the post-vaccination versus pre-vaccination interval (aOR, .973; 95% CI, .968-.978; aOR, .961; 95% CI, .953-.968, respectively). There was no association between vaccination and urinary antibiotic prescriptions (aOR, .996; 95% CI, .987-1.006). Periods with high (>10%) versus low (<5%) SARS-CoV-2 test positivity demonstrated greater reductions in antibiotic prescribing (aOR, .875; 95% CI, .845-.905; aOR, .996; 95% CI, .989-1.003, respectively). CONCLUSIONS: COVID-19 vaccination was associated with reduced outpatient antibiotic prescribing in older adults, especially during periods of high SARS-CoV-2 circulation.

Puberty Suppression for Pediatric Gender Dysphoria and the Child's Right to an Open Future.

In this essay, we consider the clinical and ethical implications of puberty blockers for pediatric gender dysphoria through the lens of "the child's right to an open future," which refers to rights that children do not have the capacity to exercise as minors, but that must be protected, so they can exercise them in the future as autonomous adults. We contrast the open future principle with the beliefs underpinning the gender affirming care model and discuss implications for consent. We evaluate claims that puberty blockers are reversible, discuss the scientific uncertainty about long-term benefits and harms, summarize international developments, and examine how suicide has been used to frame puberty suppression as a medically necessary, lifesaving treatment. In discussing these issues, we include relevant empirical evidence and raise questions for clinicians and researchers. We conclude that treatment pathways that delay decisions about medical transition until the child has had the chance to grow and mature into an autonomous adulthood would be most consistent with the open future principle.

The impact of the COVID-19 pandemic on blood culture practices and bloodstream infections.

IMPORTANCE: Bacterial infections are a significant cause of morbidity and mortality worldwide. In the wake of the COVID-19 pandemic, previous studies have demonstrated pandemic-related shifts in the epidemiology of bacterial bloodstream infections (BSIs) in the general population and in specific hospital systems. Our study uses a large, comprehensive data set stratified by setting [community, long-term care (LTC), and hospital] to uniquely demonstrate how the effect of the COVID-19 pandemic on BSIs and testing practices varies by healthcare setting. We showed that, while the number of false-positive blood culture results generally increased during the pandemic, this effect did not apply to hospitalized patients. We also found that many infections were likely under-recognized in patients in the community and in LTC, demonstrating the importance of maintaining healthcare for these groups during crises. Last, we found a decrease in infections caused by certain pathogens in the community, suggesting some secondary benefits of pandemic-related public health measures.

Newborn and Early Infant Outcomes Following Maternal COVID-19 Vaccination During Pregnancy.

Importance: The study team previously showed that maternal mRNA COVID-19 vaccination during pregnancy confers protection against SARS-CoV-2 infection and COVID-19-related hospital admission in newborns and young infants. In this study, the study team evaluated newborn and early infant safety outcomes following maternal messenger RNA (mRNA) COVID-19 vaccination during pregnancy, for which there is limited comparative epidemiological evidence. Objective: To determine if maternal mRNA COVID-19 vaccination during pregnancy is associated with adverse newborn and early infant outcomes. Design, Setting, and Participants: This population-based retrospective cohort study took place in Ontario, Canada, using multiple linked health administrative databases. Singleton live births with an expected delivery date between May 1, 2021, and September 2, 2022, were included. Data were analyzed from January 2023 through March 2023. Exposure: Maternal mRNA COVID-19 vaccination (1 or more doses) during pregnancy. Main Outcomes and Measures: Severe neonatal morbidity (SNM), neonatal death, neonatal intensive care unit (NICU) admission, neonatal readmission, and hospital admission up to 6 months of age. The study team calculated inverse probability of treatment weighted risk ratios (RRs) and fit weighted Cox proportional hazards regression models comparing outcomes in infants of mothers who received COVID-19 vaccination during pregnancy with those who received no COVID-19 vaccine doses before delivery. Results: In total, 142 006 infants (72 595 male [51%]; mean [SD] gestational age at birth, 38.7 [1.7] weeks) were included; 85 670 were exposed to 1 or more COVID-19 vaccine doses in utero (60%). Infants of vaccinated mothers had lower risks of SNM (vaccine exposed 7.3% vs vaccine unexposed 8.3%; adjusted RR [aRR], 0.86; 95% CI, 0.83-0.90), neonatal death (0.09% vs 0.16%; aRR, 0.47; 95% CI, 0.33-0.65), and NICU admission (11.4% vs 13.1%; aRR, 0.86; 95% CI, 0.83-0.89). There was no association between maternal vaccination during pregnancy and neonatal readmission (5.5% vs 5.1%; adjusted hazard ratio, 1.03; 95% CI, 0.98-1.09) or 6-month hospital admission (8.4% vs 8.1%; adjusted hazard ratio, 1.01; 95% CI, 0.96-1.05). Conclusions and Relevance: In this population-based cohort study in Ontario, Canada, maternal mRNA COVID-19 vaccination during pregnancy was associated with lower risks of SNM, neonatal death, and NICU admission. In addition, neonatal and 6-month readmissions were not increased in infants of mothers vaccinated during pregnancy.

Vancomycin Therapeutic Drug Monitoring: A Cross-Sectional Survey of Canadian Hospitals.

Background: Little is known about the current landscape of vancomycin therapeutic drug monitoring (TDM) in Canadian hospitals, which operate within publicly funded health care systems. Objectives: To determine current TDM practices for vancomycin and associated challenges and to gather perceptions about TDM based on area under the concentration-time curve (AUC) in Canadian hospitals. Methods: An electronic survey was distributed to hospital pharmacists in spring 2021 through multiple national and provincial antimicrobial stewardship, public health, and pharmacy organizations. The survey gathered data about hospital characteristics, TDM methods, inclusion criteria for patient selection, pharmacokinetic and pharmacodynamic targets, vancomycin susceptibility testing and reporting, and perceived barriers and challenges. Results: In total, 120 pharmacists from 10 of the 13 provincial and territorial jurisdictions in Canada, representing 12.5% of Canadian acute care hospitals (n = 962), completed at least 90% of survey questions. The predominant TDM method was trough-based (107/119, 89.9%); another 10.1% of respondents (12/119) reported performing AUC-based TDM (with or without trough-based TDM), and 17.9% (19/106) of those not already using AUC-based TDM were considering implementing it within 1 to 2 years. Among hospitals performing trough-based TDM, 60.5% (66/109) targeted trough levels between 15 and 20 mg/L for serious infections with methicillin-resistant Staphylococcus aureus. One-quarter of the respondents using this method (27/109, 24.8%) agreed that trough-based TDM was of uncertain benefit, and about one-third (33/109, 30.3%) were neutral on this question. Multiple challenges were identified for trough-based TDM, including sub- or supra-therapeutic concentrations and collection of specimens at inappropriate times. Overall, 40.5% (47/116) of respondents agreed that AUC-based TDM was likely safer than trough-based TDM, whereas 23.3% (27/116) agreed that AUC-based TDM was likely more effective. Conclusions: This survey represents a first step in developing evidence-based, standardized best practices for vancomycin TDM that are uniquely suited to the Canadian health care system.

Contexte: On connaît peu de choses sur le paysage actuel du suivi thérapeutique pharmacologique (STP) de la vancomycine dans les hôpitaux canadiens, dont les activités s'inscrivent dans le cadre des systèmes de soins de santé financés par les deniers publics. Objectifs: Déterminer les pratiques actuelles de STP de la vancomycine et les défis associés et recueillir les perceptions concernant le STP sur la base de l'aire sous la courbe de la concentration en fonction du temps (ASC) dans les hôpitaux canadiens. Méthodes: Un sondage a été distribué électroniquement aux pharmaciens d'hôpitaux au printemps 2021 par plusieurs organismes nationaux et provinciaux de gestion de l'utilisation des antimicrobiens, de santé publique et de pharmacie. Le sondage a permis de rassembler des données concernant les caractéristiques des hôpitaux, les méthodes de STP, les critères d'inclusion pour la sélection des patients, les objectifs pharmacocinétiques et pharmacodynamiques, les tests de sensibilité à la vancomycine et les rapports des résultats, ainsi que les obstacles et les défis perçus. Résultats: Au total, 120 pharmaciens de 10 des 13 provinces et territoires du Canada, représentant 12,5 % des hôpitaux canadiens de soins actifs (n = 962), ont répondu à au moins 90 % des questions du sondage. La méthode de STP prédominante utilisée était celle de la concentration minimale (107/119, 89,9 %); un autre 10,1 % des répondants (12/119) ont déclaré effectuer un STP basé sur l'ASC (avec ou sans STP basé sur la concentration minimale), et 17,9 % (19/106) de ceux qui n'effectuaient pas déjà le STP basé sur l'ASC envisageaient de le mettre en œuvre d'ici 1 à 2 ans. Parmi les hôpitaux pratiquant le STP basé sur la concentration minimale, 60,5 % (66/109) ciblaient des concentrations minimales entre 15 et 20 mg/L pour les infections graves à Staphylococcus aureus résistant à la méthicilline. Un quart des répondants qui utilisaient cette méthode (27/109, 24,8 %) convenaient que les avantages du STP basé sur la concentration minimale étaient incertains, et environ un tiers (33/109, 30,3 %) étaient neutres. De multiples défis ont été identifiés pour le STP basé sur la concentration minimale, notamment des concentrations sous-ou supra-thérapeutiques et la collecte d'échantillons à des moments inappropriés. Dans l'ensemble, 40,5 % (47/116) des répondants convenaient que le STP basé sur l'ASC était probablement plus sûr que le STP basé sur la concentration minimale, tandis que 23,3 % (27/116) convenaient que le STP basé sur l'ASC était probablement plus efficace. Conclusions: Ce sondage représente une première étape dans l'élaboration de pratiques exemplaires normalisées et fondées sur des données probantes pour le STP de la vancomycine qui sont particulièrement adaptées au système de santé canadien.

Iatrogenic Harm in Gender Medicine.

Although transition regret and detransition are often dismissed as rare, the increasing number of young detransitioners who have come forward in recent years to publicly share their experiences suggests that there are cracks in the gender-affirmation model of care that can no longer be ignored. In this commentary, I argue that the medical community must find ways to have more open discussions and commit to research and clinical collaboration so that regret and detransition really are vanishingly rare outcomes. Moving forward, we must recognize detransitioners as survivors of iatrogenic harm and provide them with the personalized medicine and supports they require.

Transition Regret and Detransition: Meanings and Uncertainties.

Gender transition is undertaken to improve the well-being of people suffering from gender dysphoria. However, some have argued that the evidence supporting medical interventions for gender transition (e.g., hormonal therapies and surgery) is weak and inconclusive, and an increasing number of people have come forward recently to share their experiences of transition regret and detransition. In this essay, I discuss emerging clinical and research issues related to transition regret and detransition with the aim of arming clinicians with the latest information so they can support patients navigating the challenges of regret and detransition. I begin by describing recent changes in the epidemiology of gender dysphoria, conceptualization of transgender identification, and models of care. I then discuss the potential impact of these changes on regret and detransition; the prevalence of desistance, regret, and detransition; reasons for detransition; and medical and mental healthcare needs of detransitioners. Although recent data have shed light on a complex range of experiences that lead people to detransition, research remains very much in its infancy. Little is known about the medical and mental healthcare needs of these patients, and there is currently no guidance on best practices for clinicians involved in their care. Moreover, the term detransition can hold a wide array of possible meanings for transgender-identifying people, detransitioners, and researchers, leading to inconsistences in its usage. Moving forward, minimizing harm will require conducting robust research, challenging fundamental assumptions, scrutinizing of practice patterns, and embracing debate.

Current therapies and challenges for the treatment of Staphylococcus aureus biofilm-related infections.

Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and contributes to significant increase in morbidity and mortality especially when associated with medical devices and in biofilm form. Biofilm structure provides a pathway for the enrichment of resistant and persistent phenotypes of S. aureus leading to relapse and recurrence of infection. Minimal diffusion of antibiotics inside biofilm structure leads to heterogeneity and distinct physiological activity. Additionally, horizontal gene transfer between cells in proximity adds to the challenges associated with eradication of biofilms. This narrative review focuses on biofilm-associated infections caused by S. aureus, the impact of environmental conditions on biofilm formation, interactions inside biofilm communities, and the clinical challenges that they present. Conclusively, potential solutions, novel treatment strategies, combination therapies, and reported alternatives are discussed.

Nirsevimab: review of pharmacology, antiviral activity and emerging clinical experience for respiratory syncytial virus infection in infants.

Respiratory syncytial virus (RSV) is a leading cause of hospitalization and infant mortality worldwide. There are currently no approved vaccines against RSV, and immunoprophylaxis with the mAb palivizumab is limited to extremely vulnerable infants in resource-rich settings due to its high cost and the need for monthly injections throughout the RSV season. Nirsevimab (formerly MEDI8897) is a highly potent, long-acting, human, recombinant mAb that received approval for the prevention of RSV infection in newborns and infants during their first RSV season from the EMA and the UK's Medicines and Healthcare products Regulatory Agency in November 2022 based on positive results in Phase 2b and 3 clinical trials. Nirsevimab targets the highly conserved site Ø of the prefusion conformation of the RSV fusion (F) protein and contains a triple amino acid substitution in the Fc domain that extends its half-life, allowing for a single dose to cover a typical RSV season in regions with temperate climates. In this article I review key attributes of nirsevimab with an emphasis on pharmacology, pharmacokinetics, antiviral activity, and the potential for resistance and escape variants. I also summarize current progress in clinical trials and consider future research priorities.

Estimated Effectiveness of Postpartum Maternal Messenger RNA COVID-19 Vaccination Against Delta and Omicron SARS-CoV-2 Infection and Hospitalization in Infants Younger Than 6 Months.

This case-control study estimates the effectiveness of maternal postpartum messenger RNA (mRNA) COVID-19 vaccination against Delta and Omicron SARS-CoV-2 infection and hospitalization in infants younger than 6 months.

Maternal mRNA covid-19 vaccination during pregnancy and delta or omicron infection or hospital admission in infants: test negative design study.

OBJECTIVE: To estimate the effectiveness of maternal mRNA covid-19 vaccination during pregnancy against delta and omicron severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and hospital admission in infants. DESIGN: Test negative design study. SETTING: Community and hospital testing in Ontario, Canada. PARTICIPANTS: Infants younger than six months of age, born between 7 May 2021 and 31 March 2022, who were tested for SARS-CoV-2 between 7 May 2021 and 5 September 2022. INTERVENTION: Maternal mRNA covid-19 vaccination during pregnancy. MAIN OUTCOME MEASURES: Laboratory confirmed delta or omicron infection or hospital admission of the infant. Multivariable logistic regression estimated vaccine effectiveness, with adjustments for clinical and sociodemographic characteristics associated with vaccination and infection. RESULTS: 8809 infants met eligibility criteria, including 99 delta cases (4365 controls) and 1501 omicron cases (4847 controls). Infant vaccine effectiveness from two maternal doses was 95% (95% confidence interval 88% to 98%) against delta infection and 97% (73% to 100%) against infant hospital admission due to delta and 45% (37% to 53%) against omicron infection and 53% (39% to 64%) against hospital admission due to omicron. Vaccine effectiveness for three doses was 73% (61% to 80%) against omicron infection and 80% (64% to 89%) against hospital admission due to omicron. Vaccine effectiveness for two doses against infant omicron infection was highest with the second dose in the third trimester (53% (42% to 62%)) compared with the first (47% (31% to 59%)) or second (37% (24% to 47%)) trimesters. Vaccine effectiveness for two doses against infant omicron infection decreased from 57% (44% to 66%) between birth and eight weeks to 40% (21% to 54%) after 16 weeks of age. CONCLUSIONS: Maternal covid-19 vaccination with a second dose during pregnancy was highly effective against delta and moderately effective against omicron infection and hospital admission in infants during the first six months of life. A third vaccine dose bolstered protection against omicron. Effectiveness for two doses was highest with maternal vaccination in the third trimester, and effectiveness decreased in infants beyond eight weeks of age.

Nephrotoxicity of Vancomycin in Combination With Beta-Lactam Agents: Ceftolozane-Tazobactam vs Piperacillin-Tazobactam.

BACKGROUND: Vancomycin (VAN)-associated acute kidney injury (AKI) is increased when VAN is combined with certain beta-lactams (BLs) such as piperacillin-tazobactam (TZP) but has not been evaluated with ceftolozane-tazobactam (C/T). Our aim was to investigate the AKI incidence of VAN in combination with C/T (VAN/C/T) compared with VAN in combination to TZP (VAN-TZP). METHODS: We conducted a multicenter, observational, comparative study across the United States. The primary analysis was a composite outcome of AKI and risk, injury, failure, loss, end stage renal disease; Acute Kidney Injury Network; or VAN-induced nephrotoxicity according to the consensus guidelines. Multivariable logistic regression analysis was conducted to adjust for confounding variables and stratified Kaplan-Meir analysis to assess the time to nephrotoxicity between the 2 groups. RESULTS: We included VAN/C/T (n = 90) and VAN-TZP (n = 284) at an enrollment ratio of 3:1. The primary outcome occurred in 12.2% vs 25.0% in the VAN-C/T and VAN-TZP groups, respectively (P = .011). After adjusting for confounding variables, VAN-TZP was associated with increased odds of AKI compared with VAN-C/T; with an adjusted odds ratio of 3.308 (95% confidence interval, 1.560-6.993). Results of the stratified Kaplan-Meir analysis with log-rank time-to-nephrotoxicity analysis indicate that time to AKI was significantly shorter among patients who received VAN-TZP (P = .004). Cox proportional hazards analysis demonstrated that TZP was consistent with the primary analysis (P = .001). CONCLUSIONS: Collectively, our results suggest that the AKI is not likely to be related to tazobactam but rather to piperacillin, which is a component in VAN-TZP but not in VAN-C/T.

Inclusion of pregnant and breastfeeding women in nonobstetrical randomized controlled trials.

BACKGROUND: There is an urgent need to prioritize and expedite the inclusion of pregnant and breastfeeding women in research. Characterizing trials that have successfully included these populations could inform the design and execution of future studies. In addition, up-to-date data on their inclusion in clinical research could assist in setting benchmarks, establishing targets, and monitoring progress toward more equitable inclusion. OBJECTIVE: This study aimed to characterize the eligibility and enrollment of pregnant and breastfeeding women in randomized controlled trials evaluating interventions for nonobstetrical conditions experienced by, but not limited to, these populations. STUDY DESIGN: We developed a literature search in collaboration with an information specialist. We included randomized controlled trials published between 2017 and 2019 in the 5 highest-impact general medicine journals and the 3 highest-impact specialty journals in cardiovascular disease, critical care, general infectious diseases, HIV, and psychiatry. We included randomized controlled trials that evaluated screening, diagnosis, prevention, or treatment of nonobstetrical medical conditions. We excluded randomized controlled trials exclusively focused on males, pediatrics, geriatrics, oncology, or postmenopausal women, and publications reporting subgroup, pooled, or follow-up analyses of previously published randomized controlled trials. We screened titles and abstracts independently and in duplicate, with discrepancies resolved by a third reviewer. We entered data into a standardized electronic case report form. We reviewed study protocols, appendices, and trial registries for additional data. RESULTS: Of the 1333 randomized controlled trials, pregnant and breastfeeding women were eligible for 13 (1.0%) and 6 (0.5%), respectively. Pregnancy and breastfeeding eligibility criteria were not addressed in 383 of 1333 (28.7%) and 710 of 1333 (53.3%) randomized controlled trials, respectively. In total, 102 of 937 (10.9%) and 33 of 617 (5.3%) randomized controlled trials that explicitly excluded pregnant and breastfeeding women documented the rationale. Most studies excluding pregnant women (542/937; 57.8%) required at least 1 method of contraception and/or pregnancy testing as part of trial participation for women with reproductive capacity. Among the 13 randomized controlled trials that allowed inclusion of pregnant women, 3 restricted eligibility to specific trimesters. Two randomized controlled trials enrolled pregnant women after the first year of the study following interim review of safety results in nonpregnant participants. Four randomized controlled trials reported the number of pregnant women enrolled, which ranged from 0.7% to 3.4% of the study population. None of the studies reported on pregnancy or perinatal outcomes. Compared with randomized controlled trials that excluded pregnant women, those including them more commonly had an infectious disease focus (12/13 [92.3%] vs 270/937 [28.8%]; p<.0001), including HIV (5/13 [38.5%] vs 96/937 [10.2%]; p=.0079), enrolled participants in sub-Saharan Africa (5/13 [38.5%] vs 111/937 [11.8%]; p=.0143), and had exclusively nonindustry sponsorship (13/13 [100%] vs 559/937 [59.7%]; p=.0025); inclusion varied by study phase, randomization level, and intervention type. CONCLUSION: This study illustrates a major inequity in research involving pregnant and breastfeeding women. As new health challenges arise, including novel pandemics, and the research community mobilizes to develop therapies and innovate in patient care, it is crucial that pregnant and breastfeeding women not be left behind. Greater regulatory support, in the form of explicit requirements and incentives, will be needed to ensure these populations are integrated into the research agenda.

Tocilizumab for coronavirus disease 2019 in pregnancy and lactation: a narrative review.

BACKGROUND: Tocilizumab is a monoclonal antibody that interrupts interleukin-6 signalling, reducing downstream effects on inflammation and the innate immune response. It was shown to reduce mortality in patients with severe or critical coronavirus disease 2019 (COVID-19). Pregnant and breastfeeding people were largely excluded from clinical trials and hence, the extent to which results can be applied to these populations is not clear. OBJECTIVES: To synthesize published data on tocilizumab in pregnancy and lactation, highlight important knowledge gaps, and help inform clinical decision-making about tocilizumab's use in these populations with COVID-19. SOURCES: PubMed was searched for studies evaluating tocilizumab in pregnancy and lactation for COVID-19 and other indications. Literature on pharmacokinetics and reproductive/fetal safety of monoclonal antibodies in general was also sought. The US Food and Drug Administration and the European Medicines Agency guidance for the industry and regulatory approval documents were reviewed. CONTENT: Published data on tocilizumab in pregnancy include 610 cases (n = 20 with COVID-19) together with seven mother-infant breastfeeding pairs. Higher rates of spontaneous abortion and premature birth have been reported compared with the general population, but multiple confounding variables limit interpretation. There is little data on tocilizumab exposure in the second and third trimesters when transplacental transport is highest. The effects of tocilizumab on the developing immune system are unclear. Pregnant patients with COVID-19 who received tocilizumab were often critically ill and corticosteroid use was uncommon. Neonatal follow up was limited. Tocilizumab appears to be compatible with breastfeeding. IMPLICATIONS: Although the available data do not raise serious safety signals, they have significant limitations and are not sufficient to delineate the complete spectrum of potential adverse outcomes that may be associated with tocilizumab exposure during pregnancy and lactation. Diligent follow up and documentation of pregnancy outcomes will be important moving forward. A more effective regulatory framework to ensure equitable inclusion of pregnant people in research is clearly needed.

Characterizing the inclusion of pregnant and breastfeeding people in infectious diseases randomized controlled trials: a targeted literature review.

OBJECTIVES: Severe complications of infectious diseases can occur during pregnancy. Evidence-based prevention and treatment strategies are critical to improve maternal and neonatal health outcomes. Despite this medical need, pregnant and breastfeeding people have been systematically excluded from biomedical research. The objective of this study was to characterize representation of pregnant and breastfeeding people in randomized controlled trials (RCTs) evaluating a broad range of interventions for infectious diseases. METHODS: Pregnancy and breastfeeding inclusion criteria were examined in infectious diseases RCTs published between 1 January 2017, and 31 December 2019, in the top five highest impact general medicine and the top three highest impact infectious diseases and HIV journals. RESULTS: Of 376 RCTs, 5.3% and 1.9% included pregnant and breastfeeding people, respectively. Justification for exclusion was documented in 36/271 (13.3%) studies that explicitly excluded pregnant people. Most studies excluding pregnant people (177/271, 65.3%) required at least one form of contraception, abstinence and/or negative pregnancy test(s) as part of participation. Only 11/271 (4.1%) studies excluding pregnant people allowed participants to continue the intervention if unintended pregnancy occurred during the study. When both pregnant and non-pregnant people were eligible, pregnant people made up <3% of participants. Only 2/48 (4.2%) vaccine studies included pregnant people; 13/234 (5.5%) drug studies included pregnant people. All studies of procedures, devices, behaviour/education and supplements/vitamins explicitly excluded or did not address pregnancy eligibility criteria. Only 2/20 (10.0%) RCTs including pregnant people collected pharmacokinetic data. DISCUSSION: This study demonstrates widespread exclusion of pregnant and breastfeeding people from infectious disease RCTs.

Role of maternal COVID-19 vaccination in providing immunological protection to the newborn.

Pregnant and postpartum individuals are known to have an elevated risk of severe COVID-19 compared with their non-pregnant counterparts. Vaccination is the most important intervention to protect these populations from COVID-19-related morbidity and mortality. An added benefit of maternal COVID-19 vaccination is transfer of maternal immunity to newborns and infants, for whom a vaccine is not (yet) approved. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific binding and neutralizing antibodies are present in infant cord blood and breast milk following natural maternal infection and transfer of maternal immunity following COVID-19 vaccination is an area of active research. In this review, we synthesize the available research, discuss knowledge gaps, and outline factors that should be evaluated and reported when studying the transfer of maternal immunity following COVID-19 vaccination. The data reviewed herein suggest that maternal SARS-CoV-2-specific binding antibodies are efficiently transferred via the placenta and breast milk following maternal mRNA COVID-19 vaccination. Moreover, antibodies retain strong neutralizing capacity. Antibody concentrations appear to be at least as high in infant cord blood as in the maternal serum, but lower in breast milk. Breast milk IgA rises rapidly following maternal vaccination, whereas IgG rises later but may persist longer. At least two COVID-19 vaccine doses appear to be required to reach maximal antibody concentrations in cord blood and breast milk. There is no indication that infants consuming breast milk from vaccinated mothers experience serious adverse effects, although follow-up is limited. No clear pattern has emerged regarding changes in milk supply following maternal vaccination. The heterogeneity in important methodological aspects of reviewed studies underscores the need to establish standard best practices related to research on the transfer of maternal COVID-19 vaccine-induced immunity.

Pharmacokinetic/Pharmacodynamic Considerations of Alternate Dosing Strategies of Tocilizumab in COVID-19.

Tocilizumab is one of few treatments that have been shown to improve mortality in patients with coronavirus disease 2019 (COVID-19), but increased demand has led to relative global shortages. Recently, it has been suggested that lower doses, or fixed doses, of tocilizumab could be a potential solution to conserve the limited global supply while conferring equivalent therapeutic benefit to the dosing regimens studied in major trials. The relationship between tocilizumab dose, exposure, and response in COVID-19 has not been adequately characterized. There are a number of pharmacokinetic (PK) parameters that likely differ between patients with severe COVID-19 and patients in whom tocilizumab was studied during the US FDA approval process. Likewise, it is unclear whether a threshold exposure is necessary for tocilizumab efficacy. The safety and efficacy of fixed versus weight-based dosing of tocilizumab has been evaluated outside of COVID-19, but it is uncertain if these observations are generalizable to severe or critical COVID-19. In the current review, we consider the potential advantages and limitations of alternative tocilizumab dosing strategies. Leveraging PK models and simulation analyses, we demonstrate that a fixed single dose of tocilizumab 400 mg is unlikely to produce PK exposures equivalent to those achieved in the REMAP-CAP trial, although weight-stratified dosing appears to produce more uniform exposure distribution. Data from current and future trials could provide PK/pharmacodynamic insight to better inform dosing strategies at the bedside. Ultimately, rational dosing strategies that balance available limited supply with patient needs are required.