Search

To determine invasive group A Streptococcus trends in Canada, we characterized emm1 isolates collected during 2018–2023. The percentage of hypervirulent M1UK lineage isolates increased significantly, from 22.1% in 2018 to 60.2% in 2023. Genomic analysis identified geographically and temporally associated clusters and genes associated with virulent bacteriophage acquisition.

ABSTRACT Syphilis, caused by Treponema pallidum subsp. pallidum (TPA), is becoming a significant public health concern, with rising incidence in Manitoba exceeding the national average. The province has also seen a demographic shift leading to women representing 51.9% of cases in 2021, leading to the re-emergence of congenital syphilis. Given the similarities in lesion appearance between TPA and other pathogens such as herpesviruses, accurate diagnosis is crucial for effective management and prevention. In order to address the potential for missed TPA cases, we conducted a quality assurance study from June 2021 to March 2023, screening over 5,000 mucocutaneous lesion swabs for TPA, initially submitted for herpes simplex virus (HSV) and varicella zoster virus (VZV) testing. Positivity rates were 13% for HSV1, 13% for HSV2, 6.7% for VZV, and 6.6% for TPA. Turnaround times (TAT) for TPA testing, as a send-out to the reference laboratory, averaged 17.8 days. Of the TPA-positive specimens, 36% did not have a corresponding TPA PCR test ordered, and 19% did not have accompanying syphilis serology within 30 days of collection. Creation of a multiplex lesion panel identified high sensitivity and specificity for HSV1, HSV2, VZV, and TPA, with robust reproducibility across multiple runs. Incorporation of TPA into a lesion panel improved the TAT to 4 days. Our findings emphasize the need for improved testing strategies to combat the syphilis epidemic and enhance public health outcomes.IMPORTANCESyphilis resurgence has become a significant global public health concern. In particular, the Canadian Prairies have been struggling with high incidence since 2016, exceeding the national Canadian average. We undertook a quality assurance study that highlighted significant gaps in diagnosis of acute syphilis, which led to the development of a highly sensitive and specific multiplex lesion assay for the dual detection of herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella zoster virus (VZV), and syphilis.

Understanding variables that influence antibody responses to COVID-19 vaccination within a population can provide valuable information on future vaccination strategies. In this population-based study, we examined the antibody responses to COVID-19 vaccination in Manitoba using residual serum specimens collected between January 2021 and March 2022 (n = 20,365). Samples were tested for spike and nucleocapsid IgG against SARS-CoV-2 using clinically validated assays. We assessed the impacts of multiple factors on post-vaccination antibody titres including type of vaccine, age, sex, geographic location, number of doses received, and timing of vaccination. Our investigation demonstrated that vaccination with one dose of Moderna mRNA-1273 elicited higher anti-spike IgG titres overall compared to Pfizer BNT162b2 vaccination, while one dose of Pfizer BNT162b2 followed by a second dose of Moderna mRNA-1273 exhibited higher titres than two doses of Pfizer BNT162b2 or Moderna mRNA-1273, irrespective of age. Age and time post-vaccination had considerable effects on antibody responses, with older age groups exhibiting lower anti-spike IgG titres than younger ages, and titres of those vaccinated with Pfizer BNT162b2 waning faster than those vaccinated with Moderna mRNA-1273 or a combination of Pfizer BNT162b2 and Moderna mRNA-1273. Antibody titres did not appear to be affected by sex or geographic location. Our results identify how factors such as age and type of vaccine can influence antibody responses to vaccination, and how antibody titres wane over time. This information highlights the importance of tailoring vaccine regimens to specific populations, especially those at increased risk of severe COVID-19 and can be used to inform future vaccination strategies, scheduling of booster doses, and public health measures.

Recent mumps outbreaks have been observed in vaccinated young adults due to the mumps virus (MuV) of genotype G, whereas the current vaccine is a mixture of two genotype A strains. These outbreaks could be attributed to waning vaccine immunity or the antigenic differences between the HN and F glycoproteins in the vaccine and circulating MuV. These glycoproteins are essential targets for the immune system, and antigenic variations may reduce the recognition of mumps antibodies, rendering the population susceptible to the MuV. We established stable cell lines expressing the MuV glycoproteins to study cross-reactivity between genotype A and genotype G. Cross-reactivity between the genotypes was evaluated via immunofluorescence using patient sera from vaccinated individuals, infected individuals, and vaccinated individuals infected with genotype G. Titer ratios showed that the vaccinated individuals exhibited a titer 3.68 times higher for the HN protein and 2.3 times higher for the F protein when comparing genotype A with genotype G. In contrast, the infected individuals showed a lower titer for genotype A compared with genotype G, at 0.43 and 0.33 for the HN and F proteins, respectively. No difference in titer ratio was observed for individuals vaccinated and subsequently infected with mumps. These findings suggest that antigenic variations between the two genotypes may potentially result in immune escape of the circulating strain, resulting in individuals susceptible to the MuV.

Background: Seasonal influenza vaccine (SIV) uptake (receipt of vaccine) in Manitoba, Canada is consistently low notwithstanding vaccine availability and free-of-charge vaccination. Despite, there is a lack of published evidence on the determinants of uptake of the vaccine. We sought to assess the association between SIV uptake and certain population and primary care physician (PCP) characteristics in Manitoba. Methods: We conducted a longitudinal study utilizing Manitoba administrative health databases. We summarized SIV uptake from 2000/01–2019/20 influenza seasons across subpopulations defined by socioeconomic, health-related and PCP characteristics. Utilizing multivariable generalized estimating equation logistic regression models, we assessed the association between SIV uptake and the socioeconomic, health-related and PCP characteristics, stratified by age group (

IntroductionVaccination plays a key role in curbing severe outcomes resulting from COVID-19 disease. With the Omicron variant and the relaxing of public health protections breakthrough infections are increasingly common, and certain groups remain at higher risk for severe outcomes from breakthrough infections. We analysed population-based public health data from Manitoba, Canada to understand characteristics of those experiencing breakthrough infections and severe outcomes from breakthrough infections. Data from previous pandemic stages can provide valuable information regarding severe outcomes associated with breakthrough infection in the Omicron and future phases.MethodsPositive SARS-CoV-2 PCR tests from Cadham Provincial Laboratory were linked to case information from the population-based Public Health Information Management System. A retrospective design was used with time-to-event analyses to examine severe outcomes among those experiencing breakthrough infection.ResultsBreakthrough cases were more likely to have 2 + chronic conditions, compared to age-, sex-, and time-period matched unvaccinated cases (24% vs. 17%), with hypertension (30%), diabetes (17%), and asthma (14%) being the most prevalent chronic conditions amongst breakthrough cases. Severe outcomes resulting from breakthrough infection was associated with age and chronic conditions, with those with 2 + chronic conditions at higher risk of severe outcomes (adjusted hazard ratio: 3.6, 95% confidence intervals: 2.0-6.4). Risk of severe outcomes varied by age group, with those 70 + years at over 13 times the risk of severe outcomes (95% CI: 4.5-39.8), compared to those 18-29 years of age.DiscussionOur results demonstrate the impact of chronic conditions on the likelihood of, and severity of outcomes from breakthrough infections. These findings underscore the importance of vaccination programs prioritizing vulnerable populations.