David Goldfarb

• Professor (Associate) at BC Children's Hospital

Introduction. Comparative immunogenicity from different mRNA booster vaccines (directed at WT, BA.1 or BA.4/5 antigens) remains unclear. Methods. We included blood samples from adult paramedics who received three mRNA WT-directed vaccines plus a fourth dose of the following: (1) WT monovalent, (2) Moderna BA.1-WT bivalent or (3) Pfizer BA.4/5 WT bi...

Introduction Comparative immunogenicity from different mRNA booster vaccines (directed at wild-type [WT], BA.1, or BA.4/5 antigens) remains unclear. Methods We included blood samples from adult paramedics who received three mRNA WT-directed vaccines plus a fourth dose of: (1) WT monovalent; (2) Moderna BA.1-WT bivalent; or (3) Pfizer BA.4/5-WT biva...

Background Rotavirus vaccines are moderately protective against illness in high mortality settings compared with low mortality settings. Vaccine effectiveness (VE) evaluations may clarify our understanding of these disparities, but estimates among key subpopulations and against rare outcomes are not available in many analyses due to sample size. We...

To optimize the identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children, specimen collection and testing method are crucial considerations. Ideally, specimen collection is easy and causes minimal discomfort, and the laboratory approach is simple, accurate, and rapid. In this prospective cohort study we evalu...

This study showed that a SARS-CoV-2 infection reduced the risk of reinfection among vaccinated individuals by 0.50 [95%CI: 0.39–0.64] over a one-year period, after accounting for unreported infections using avidity-based serology. Reciprocally, chronic symptoms increased from a baseline of 21% [16–28%] among infection-naïve individuals to 43% [30–6...

Introduction The role of computed tomography (CT) prior to lumbar puncture (LP) is unclear, with limited evidence for a causal link between LP and cerebral herniation or for the ability of CT to identify individuals at risk of herniation. The risks of LP delay or deferral are potentially greater in high HIV-prevalence, resource-limited settings; we...

Background Successful sequencing of genomes on Oxford Nanopore Technologies (ONT) sequencing platforms is dependant on obtaining sufficient amounts of high-quality genomic DNA. ONT’s Rapid PCR kit (SQK-RPB114.24) kit is specifically designed to address input template limitations, whereby low amounts of target DNA (1–5 ng) is pre-amplified to > 100–...

Background: Multidrug-resistant Gram-negative bacteria are a major cause of sepsis among hospitalized neonates globally. Aqueous chlorhexidine gluconate (CHG) skin antisepsis has been shown to be safe for use in infants; however, its sustained effectiveness in preventing Gram-negative pathogen colonization, bloodstream infection (BSI), and mortalit...

Gullain-Barré syndrome (GBS) is an acute peripheral neuropathy often preceded by respiratory or gastrointestinal infections, though molecular testing of cerebrospinal fluid (CSF) is often inconclusive. In a recent case of severe pediatric GBS in British Columbia, Canada, we detected CSF antibodies against enterovirus D (EV-D) to link GBS with prior...

Background Canadian Arctic communities have experienced sustained syphilis transmission, with diagnoses rates 18-times higher than the national average. Remoteness from laboratory facilities leads to delays between syphilis screening and treatment, contributing to onward transmission. Rapid diagnostic tests can eliminate treatment delays via testin...

In Canada’s federated healthcare system, 13 provincial and territorial jurisdictions have independent responsibility to collect data to inform health policies. During the COVID-19 pandemic (2020–2023), national and regional sero-surveys mostly drew upon existing infrastructure to quickly test specimens and collect data but required cross-jurisdicti...

Haemophilus influenzae serotype a (Hia) has recently emerged as an important cause of invasive disease in the North American Arctic and Sub-Arctic regions, mainly affecting young Indigenous children. In this study, we addressed the question of whether the prevalence of Hia and all H. influenzae in the nasopharynx differed between paediatric populat...

Background Sepsis is a life-threatening condition which may arise from infection in any organ system and requires early recognition and management. Healthcare professionals working in any specialty may need to manage patients with sepsis. Educating medical students about this condition may be an effective way to ensure all future doctors have suffi...

Objectives. Preterm infants are at risk of hypothermia. This study described the available infant warming devices (IWDs) and explored the barriers and facilitators to their implementation in neonates in Malawi. Methods. A qualitative descriptive study was conducted among 19 health care workers in Malawi from January to March 2020. All interviews we...

Objectives To compare clinical and health systems outcomes of rapid molecular testing versus throat culture recovery for the management of group A Streptococcus (GAS) pharyngitis in a pediatric emergency department (PED). Methods We conducted a single-center randomized trial of children (3–17 years) presenting to a PED with suspected GAS pharyngit...

Background: Nunavut is a northern Canadian territory in Inuit Nunangat (Inuit homeland in Canada). Approximately 85% of the population identifies as Inuit. A high proportion of infants in Nunavut are admitted to hospital with acute respiratory tract infection (ARI) but previous studies have been limited in regional and/or short duration of coverage...

Detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections is challenging with current serology assays and is further complicated by the marked decrease in routine viral testing practices as viral transmission increased during Omicron. Here, we provide proof-of-principle that high-avidity anti-nucleocapsid (N) antibodies de...

Introduction Comparative immunogenicity from different mRNA booster vaccines (directed at wild-type [WT], BA.1, or BA.4/5 antigens) remains unclear. Methods We included blood samples from adult paramedics who received three mRNA WT-directed vaccines plus a fourth dose of: (1) WT monovalent; (2) Moderna BA.1-WT bivalent; or (3) Pfizer BA.4/5-WT biva...

Recent research has highlighted the Omicron variant’s capacity to evade immune protection conferred by wild-type (WT) mRNA vaccines. Despite this observation, the potential involvement of antigenic sin phenomena remains unclear. Our hypothesis posited that a greater number of prior WT vaccine doses might lead to reduced anti-Omicron neutralization...

Background Macrolide antibiotics, including azithromycin, can reduce under 5 years of age mortality rates and treat various infections in children in sub-Saharan Africa. These exposures, however, can select for antibiotic-resistant bacteria in the gut microbiota. Methods Our previous randomized controlled trial (RCT) of a rapid-test-and-treat stra...

Background and objectives Pediatric COVID-19 cases are often mild or asymptomatic, which has complicated estimations of disease burden using existing testing practices. We aimed to determine the age-specific population seropositivity and risk factors of SARS-CoV-2 seropositivity among children and young adults during the pandemic in British Columbi...

Background Inadequate sampling poses challenges in the COVID-19 diagnostic cycle. Nasopharyngeal swabs are gold-standard but often associated with patient discomfort, require trained healthcare workers (HCW), and are resource intensive. The saline gargle (SG) method has proven to be acceptable for respiratory pathogen detection. We performed a pros...

The coronavirus disease 2019 (COVID-19) pandemic, caused by the SARS-CoV-2 virus, has rapidly evolved since late 2019, due to highly transmissible Omicron variants. While most Canadian paramedics have received COVID-19 vaccination, the optimal ongoing vaccination strategy is unclear. We investigated neutralizing antibody (NtAb) response against wil...

Background Medical devices are critical to providing high-quality, hospital-based newborn care, yet many of these devices are unavailable in low- and middle-income countries (LMIC) and are not designed to be suitable for these settings. Target Product Profiles (TPPs) are often utilised at an early stage in the medical device development process to...

Background. We examined the 11 month longitudinal antibody decay among two-dose mRNA vaccinees, and identified factors associated with faster decay. Methods. The study included samples from the COVID-19 Occupational Risk, Seroprevalence and Immunity among Paramedics (CORSIP) longitudinal observational study of paramedics in Canada. Participants wer...

The coronavirus disease 2019 (COVID-19) pandemic, caused by the SARS-CoV-2 virus, has rapidly evolved since late 2019, due to highly transmissible Omicron variants. While most Canadian paramedics have received COVID-19 vaccination, the optimal ongoing vaccination strategy is unclear. We investigated neutralizing antibody (NtAb) response against wil...

This study investigated the association between previous SARS-CoV-2 infection and risk of symptoms associated with post COVID conditions among fully vaccinated paramedics in Canada. We included vaccinated paramedics who provided blood sample and questionnaire data on the same date during the study period. We examined the presence of symptoms associ...

The coronavirus disease 2019 (COVID-19) pandemic, caused by the SARS-CoV-2 virus, has rapidly evolved since late 2019, due to highly transmissible Omicron variants. While most Canadian paramedics have received COVID-19 vaccination, the optimal ongoing vaccination strategy is unclear. We investigated neutralizing antibody (NtAb) response against wil...

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major cause of bloodstream infection among hospitalized patients in low- and middle-income countries (LMICs). CRAB infections can be difficult to treat and are devastating in neonates (~30% mortality). CRAB outbreaks are hypothesized to arise from reservoirs in the hos...

Background We examined the 11-month longitudinal antibody decay among 2-dose mRNA vaccinees, and identified factors associated with faster decay.Methods The study included samples from the CORSIP longitudinal observational study of paramedics in Canada. Participants were included if they had received two mRNA vaccines without prior SARS-CoV-2 infec...

Background The COVID-19 pandemic has perturbed the seasonality of respiratory syncytial virus (RSV) infections. However, we lack data on how this impacted the severity of paediatric RSV cases. The objective of this study was to describe the clinical severity of RSV cases before, during and after pandemic measures in British Columbia (BC), Canada....

BACKGROUND: Pediatric COVID-19 cases are often mild or asymptomatic, which has complicated estimations of disease burden using existing testing practices. We aimed to determine the age-specific population seropositivity and risk factors of SARS-CoV-2 seropositivity among children and young adults during the pandemic in British Columbia (BC). METHOD...

Mass distribution of azithromycin has been recommended to reduce under-five mortality rates in certain countries in sub-Saharan Africa. Additionally, antibiotic treatment of children with bacterial gastroenteritis holds promise for the prevention of mortality and the optimization of linear growth. However, mass administration and imprudent prescrip...

Background We examined the 11-month longitudinal antibody decay among 2-dose mRNA vaccinees, and identified factors associated with faster decay.Methods The study included samples from the CORSIP longitudinal observational study of paramedics in Canada. Participants were included if they had received two mRNA vaccines without prior SARS-CoV-2 infec...

Carbapenem-resistant Acinetobacter baumannii (CRAb) has emerged as a major and often fatal cause of bloodstream infections among hospitalized patients in low- and middle-income countries (LMICs). CRAb outbreaks are hypothesized to arise from reservoirs in the hospital environment, but outbreak investigations in LMICs are seldom able to incorporate...

Background: Increasing the interval between the first and second SARS-CoV-2 vaccine doses enhances vaccine immunogenicity, however the optimal timing of the third vaccine is unknown. In this study, we investigated how the time interval between the first and second (V1-V2), or second and third (V2-V3) doses affects immunogenicity after three doses...

Background: Global guidelines recommend untargeted iron supplementation for women in regions of anemia prevalence ≥40%, such as Cambodia. However, the potential harms of untargeted iron on the gut have not been rigorously studied in women and likely vary depending on iron dose and form. Objective: We investigated if a lower dose of a highly bioa...

Objectives: We evaluated the field diagnostic accuracy of a syphilis rapid test (RDT), using serum and whole blood by non-laboratorians in two Canadian Arctic communities. Methods: We implemented a multisite prospective field evaluation wherein patients were screened by an RDT containing treponemal and non-treponemal components (Chembio DPP® Syp...

The World Health Organization recommends untargeted iron supplementation for women of reproductive age (WRA) in countries where anemia prevalence is greater than 40%, such as Cambodia. Iron supplements, however, often have poor bioavailability, so the majority remains unabsorbed in the colon. The gut houses many iron-dependent bacterial enteropatho...

Objective To determine the SARS-CoV-2 seroprevalence among school workers within the Greater Vancouver area, British Columbia, Canada, after the first Omicron wave. Design Cross-sectional study by online questionnaire, with blood serology testing. Setting Three main school districts (Vancouver, Richmond and Delta) in the Vancouver metropolitan ar...

As part of the COVID-19 pandemic, clinical laboratories have been faced with massive increases in testing, resulting in sample collection systems, reagent, and staff shortages. We utilized self-collected saline gargle samples to optimize high throughput SARS-CoV-2 multiplex polymerase chain reaction (PCR) testing in order to minimize cost and techn...

Introduction Previous results suggest that COVID-19 adversely impacted a number of health and coping measures among Canadian paramedics, particularly females. Estimated prevalence for meeting screening criteria for mental health disorders and suicidal thoughts were higher than previously reported. Objectives To provide an update on the impact of t...

Introduction Psychological effects of withholding treatment that could have benefited a patient during a pandemic remain largely unknown. It is also unclear to what extent their reasons for withholding treatment contributed to the subsequent impact on mental health outcomes. Paramedics may have withheld treatments either due to fear of exposure, be...

Introduction Canadian Paramedic services modified infection prevention and control (IPAC) practices in response to COVID-19. These changes may affect risk of exposure to infectious disease agents and can be used to inform future IPAC practices. We characterized COVID-19-related IPAC changes in the provinces of Alberta, British Columbia, Manitoba, O...

Objective: Emerging evidence indicates that longer SARS-CoV-2 vaccine dosing intervals results in an enhanced immune response. However, the optimal vaccine dosing interval for achieving maximum immunogenicity is unclear. Methods: This study included samples from adult paramedics in Canada who received two doses of either BNT162b2 or mRNA-1273 va...

With the growth of qualitative health research in low- and middle-income countries, local health professionals are increasingly involved in facilitating interviews with their fellow health workers. Understanding the methodological implications of such situations is required to ensure high-quality study findings and to build capacity and skills for...

Background: While breast milk is widely accepted as the best source of nutrients for almost all newborns, breastfeeding can be especially challenging for preterm and low birth weight (LBW) infants. With increased risk of admission to neonatal intensive care units (NICUs) and separation from parents, this population experiences significant barriers...

Background: The COVID-19 pandemic affected Respiratory Syncytial Virus (RSV) circulation and surveillance, causing logistical complexity for health systems. Our objective was to describe changes in epidemiology and clinical severity of RSV cases in British Columbia (BC), Canada. Methods: Comparative analysis of RSV detections in children <36 months...

Introduction Evidence-based recommendations for paediatric community-acquired pneumonia (CAP) diagnosis and management are needed. Uncomplicated CAP is often caused by respiratory viruses, especially in younger children; these episodes self-resolve without antibiotic treatment. Unfortunately, there are no clinical criteria that reliably discriminat...

Improving breastfeeding practices is key to reducing child mortality globally. Sub-optimal exclusive breastfeeding rates may be associated with inadequate hospital-based postpartum breastfeeding support, particularly in resource-limited health settings such as Malawi. While almost all children in Malawi are breastfed, it is a concern that exclusive...

Background: Investigating antibody titers in individuals who have been both naturally infected with SARS-CoV-2 and vaccinated can provide insight into antibody dynamics and correlates of protection over time. Methods: Human coronavirus (HCoV) IgG antibodies were measured longitudinally in a prospective cohort of qPCR-confirmed, COVID-19 recovere...

The relationship between antibodies to wild-type SARS-CoV-2 antigens and the risk of breakthrough infections is unclear, especially during time periods of Omicron. We investigated the association of anti-spike and anti-receptor binding domain antibody levels and the risk of subsequent breakthrough COVID-19. We included adult paramedics from an obse...

Background: Investigating antibody titres in individuals who have been both naturally infected with SARS-CoV-2 and vaccinated can provide insight into antibody dynamics and correlates of protection over time. Methods: Human coronavirus (HCoV) IgG antibodies were measured longitudinally in a prospective cohort of PCR-confirmed, COVID-19 recovered in...

Live viral neutralizing antibody titers are an accepted measure of immunity; however, testing procedures are labor-intensive. COVID-19 antibody and angiotensin converting enzyme-2 (ACE-2) levels have been used as surrogates to live viral neutralizing antibody titers; however, validity among vaccinated individuals is unclear.

Background Intense transmission of syphilis has emerged in some Canadian Arctic communities despite screening and prevention efforts. The remoteness of most communities and limited diagnostic infrastructure yield long delays (≥14 days) between screening and treatment of cases. These hamper syphilis control efforts and may contribute to sustained tr...

The SARS-CoV-2 belongs to the coronavirus family, which also includes common endemic coronaviruses (HCoVs). We hypothesized that immunity to HCoVs would be associated with stronger immunogenicity from SARS-CoV-2 vaccines. The study included samples from the COSRIP observational cohort study of adult paramedics in Canada. Participants provided blood...

Résumé Historique Le syndrome inflammatoire multisystémique de l’enfant (SIME) est une complication postinfectieuse de la COVID-19 qui combine des manifestations de la maladie de Kawasaki et du syndrome de choc toxique. En mai 2020, un groupe de travail multidisciplinaire provincial a été mis sur pied en prévision des cas émergents après la premiè...

Objectives Gathering population-based data on prevalence of SARS-CoV-2 infection is vital to the public health response and planning. Current seroprevalence data in BC are limited with respect to considerations of how socioeconomic and demographic factors, such as age, sex, gender, income, identifying as a visibility minority and occupation, are re...

Introduction: This study assessed the relationship between intention to receive a COVID-19 vaccine and intention to receive a seasonal influenza vaccine, as well as how intention to receive a COVID-19 vaccine has changed during the pandemic. Methods: Residents of British Columbia aged 25–69 years were invited to complete an online cross-sectional s...

Background The incidence of hospitalizations for acute respiratory infections (ARI) among young Indigenous children from Northern Canada is consistently high. ARIs requiring urgent air transfer can be life-threatening and costly. We aimed to describe their epidemiology, estimate age-specific incidences, and explore factors associated with level of...

Nucleocapsid serological assay sensitivity to identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among vaccinees and for Omicron cases is unclear. In this prospective study, the Elecsys nucleocapsid assay was 89% sensitive in identifying SARS-CoV-2 infections 14-607 days pre-blood collection. Sensitivity was similar wh...

We prospectively studied SARS-CoV-2 transmission at schools in an era of variants of concern, offering all close contacts serial viral asymptomatic testing up to 14 days. From the 69 primary cases detected in schools, 392 close contacts were identified and offered asymptomatic testing. A total of 229 (58%) were close school contacts, and of these,...

Objective To determine the SARS-CoV-2 seroprevalence among school workers in the setting of full in-person schooling and the highly transmissible Omicron variants of concern. Design Cross-sectional study among school staff, comparing to period-, age-, sex- and postal code-weighted data from Canadian blood donors from the same community. Setting T...

Background Severe neonatal jaundice can result in long term morbidities and mortality when left untreated. Phototherapy is the main-stay intervention for treating moderate jaundice and for prevention of the development of severe jaundice. However, in resource-limited health care settings, phototherapy has been inconsistently used. The objective of...

The prevalence and clinical relevance of Human herpesvirus-6 (HHV-6) detection in cerebrospinal fluid (CSF) using multiplex PCR testing in patients with suspected meningoencephalitis in high HIV-prevalence African settings are not known. We describe the clinical and laboratory characteristics of 13 patients with HHV-6 CSF PCR-positivity in Botswana...

Background Multisystem Inflammatory Syndrome in Children (MIS-C) is a post-infectious complication of SARS-CoV-2 infection with overlapping features of Kawasaki disease and toxic shock syndrome. In May 2020, a provincial multidisciplinary working group was established in anticipation of emerging cases following the first wave of SARS-CoV-2 infectio...

Background The purpose of this study was to explore factors associated with COVID-19 vaccine intentions among school staff as high vaccine uptake is essential to ensure schools return to normal activities. Methods Staff (e.g., teachers, administrators, student support workers) from three urban school districts in the Greater Vancouver Area of Brit...

Sapoviruses are an important cause of acute viral gastroenteritis in children. The objective of this study was to determine the burden and genetic diversity of sapoviruses in children hospitalized with acute gastroenteritis in Botswana between 2016 and 2018. Samples were screened using the BioFire® Filmarray® GI Panel assay and for positive sapovir...

Objectives Few studies reported COVID-19 cases in schools during the 2020/21 academic year in a setting of uninterrupted in-person schooling. The main objective was to determine the SARS-CoV-2 seroprevalence among school staff in Vancouver public schools. Design Cumulative incident COVID-19 cases among all students and school staff based on public...

Introduction The study aim was to determine if rapid enteric diagnostics followed by the provision of targeted antibiotic therapy (‘test-and-treat’) and/or Lactobacillus reuteri DSM 17938 would improve outcomes in children hospitalised in Botswana with acute gastroenteritis. Methods This was a multicentre, randomised, factorial, controlled, trial....

Study objective SARS-CoV-2 represents an occupational risk to paramedics, who work in uncontrolled environments. We sought to identify the occupation-specific risk to paramedics by comparing their seroprevalence of SARS-CoV-2 infection-specific antibodies to that of blood donors in Canada. Methods In this prospective cohort study, we performed ser...

We investigate the diagnostic accuracy and predictive value of finger prick capillary dried blood spot (DBS) samples tested by a quantitative multiplex anti-immuno-globulin G (IgG) assay to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies after infection or vaccination. This cross-sectional study involved participants...

ABSTRACT While mRNA vaccines are highly efficacious against short-term COVID-19, long-term immunogenicity is less clear. We compared humoral immunogenicity between BNT162b2 and mRNA-1273 vaccines 6 months after the first vaccine dose, examining the wild-type strain and multiple Delta-variant lineages. Using samples from a prospective observational...

Objective Emerging evidence indicates that longer SARS-CoV-2 vaccine dosing intervals results in an enhanced immune response. However, the optimal vaccine dosing interval for achieving maximum immunogenicity is unclear. Methods This study included samples from adult paramedics in Canada who received two doses of either BNT162b2 or mRNA-1273 vaccin...

Background Human milk insufficiency is a significant barrier to implementing breastfeeding, and it is identified as a prevalent concern in 60–90% of mothers in low-and-middle-income countries. Breastmilk insufficiency can lead to hypoglycemia, hypernatremia, nutritional deficiencies, and failure to thrive in newborns and infants. Studies investigat...

Among a cohort of adult paramedics in Canada, we investigated the performance of nucleocapsid (N) antibody detection (measured with a V-PLEX assay) to identify previous COVID-19 infections and compared differences among vaccinated and unvaccinated. Our data indicate that vaccinated and unvaccinated groups require different thresholds to achieve opt...

Introduction Infections due to extended spectrum beta-lactamase producing organisms (ESBL) have emerged as the leading cause of sepsis among hospitalized neonates in Botswana and much of sub-Saharan Africa and south Asia. Yet, ESBL reservoirs and transmission dynamics within the neonatal intensive care unit (NICU) environment are not well-understoo...

The true severity of infection due to COVID-19 is under-represented because it is based on only those who are tested. Although nucleic acid amplifications tests (NAAT) are the gold standard for COVID-19 diagnostic testing, serological assays provide better population-level SARS-CoV-2 prevalence estimates. Implementing large sero-surveys present sev...

This study investigates the immunogenicity of extended mRNA vaccine dosing intervals.

Background Sub-Saharan Africa carries a disproportionate burden of under-five child deaths in the world and appropriate breastfeeding practices can support efforts to reduce child mortality rates. Health facilities are important in the promotion of early and exclusive breastfeeding. The purpose of this review was to examine facility-based barriers...