Investigating incidence of and factors associated with SARS-CoV-2 infection over a nine-month period in a highly-vaccinated healthcare worker cohort.

BACKGROUND: Healthcare workers (HCWs) are at increased risk of SARS-CoV-2 infection. This risk persists despite the implementation of mitigating factors, including vaccination. The ongoing impact of incident SARS-CoV-2 infection and symptomatic COVID-19 disease in vaccinated healthcare workers is poorly understood. AIM: We aimed to describe the epidemiology of incident SARS-CoV-2 infections, as well as investigating the serological, clinical and demographic factors associated with developing infection. DESIGN: This was a multi-centre prospective longitudinal study followed a HCW cohort over a nine-month period. METHODS: Spike and nucleocapsid SARS-CoV-2 antibodies were measured at enrolment. Vaccination status, demographics, and medical history were collated. Incident infection over the study period was recorded. Multivariable regression models investigated factors associated with nucleocapsid antibody status, incident infection, and symptomatic infection. RESULTS: 1,260 participants took part, of whom n = 1,006 were anti-nucleocapsid antibody positive. Negative anti-nucleocapsid antibody was associated with older age and having a known SARS-CoV-2 acquisition risk. There were n = 274 (22%) incident infections, with n = 225 (87%) diagnosed using antigen tests. Incident infections were associated with lower anti-nucleocapsid titres, increased time since previous SARS-CoV-2 infection, and having a known acquisition risk, but were not associated with vaccination status. CONCLUSIONS: This study demonstrates a high rate of incident SARS-CoV-2 infection amongst healthcare workers, despite broad vaccine coverage. There is a shift in diagnostics, from PCR to antigen testing. We identify at-risk groups for incident infection, and these should continue be targeted as part of risk reduction campaigns. Vaccination status and prior infection status alone are not surrogates for protection.

Health Care Personnel Workdays Lost and Direct Health Care Salary Costs Incurred due to COVID-19 Infection in the Age of Widespread Vaccine Availability.

BACKGROUND: Vaccination against coronavirus disease 2019 (COVID-19) can mitigate the burden of health care worker (HCW) infection. We investigate the burden of HCW illness and its associated direct health care personnel costs in the setting of widespread vaccine availability and explore factors influencing these outcomes. METHODS: This multicenter prospective study followed HCWs over an 8-month period from January to August 2023. Data recorded included incident COVID-19 infection, symptom burden, workdays missed, and vaccine history. Workdays lost due to illness were used to calculate direct health care personnel costs due to COVID-19 infection. Univariate analysis and multivariable regression investigated the factors associated with workdays lost and direct health care personnel. RESULTS: In total, 1218 participants were enrolled and followed for 8 months, with 266 incidents of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, 1191 workdays lost, and health care personnel costs of €397 974. Multivariable regression revealed that workdays lost were associated with incomplete primary COVID-19 vaccination course. Being unvaccinated, older age, and male were associated with increased health care personnel costs. CONCLUSIONS: Health care workdays lost remain a significant issue and are associated with health care system burden despite vaccine availability. These can be mitigated via targeted implementation of vaccine programs. Seasonal variation in health care workdays lost should inform workforce planning to accommodate surge periods.

Healthcare Worker Characteristics Associated with SARS-CoV-2 Vaccine Uptake in Ireland; a Multicentre Cross-Sectional Study.

The prevention of SARS-CoV-2 acquisition and transmission among healthcare workers is an ongoing challenge. Vaccination has been introduced to mitigate these risks. Vaccine uptake varies among healthcare workers in the absence of vaccine mandates. We investigated engagement with SARS-CoV-2 vaccination among healthcare workers and identified characteristics associated with lower vaccine uptake. This multi-site cross-sectional study recruited n = 1260 healthcare workers in both clinical and non-clinical roles over a three-month period from November 2022. Participants reported their engagement with the primary SARS-CoV-2 vaccination programme and subsequent booster programmes, as well as providing demographic, occupational and personal medical history information. Multivariable linear regression identified characteristics associated with vaccine uptake. Engagement with vaccination programmes was high, with 88% of participants receiving at least one booster dose after primary vaccination course. Younger age and female sex were associated with reduced vaccine uptake. Healthcare workers in non-clinical roles also had reduced vaccine uptake. These findings should inform vaccination strategies across healthcare settings and target populations with reduced vaccine uptake directly, in particular young, female, and non-clinical healthcare workers, both for SARS-CoV-2 and other healthcare-associated vaccine-preventable infections.

Point of care detection of SARS-CoV-2 antibodies and neutralisation capacity-lateral flow immunoassay evaluation compared to commercial assay to inform potential role in therapeutic and surveillance practices.

Introduction: As the COVID-19 pandemic moves towards endemic status, testing strategies are being de-escalated. A rapid and effective point of care test (POCT) assessment of SARS-CoV-2 immune responses can inform clinical decision-making and epidemiological monitoring of the disease. This cross-sectional seroprevalence study of anti-SARS-CoV-2 antibodies in Irish healthcare workers assessed how rapid anti-SARS-CoV-2 antibody testing can be compared to a standard laboratory assay, discusses its effectiveness in neutralisation assessment and its uses into the future of the pandemic. Methods: A point of care lateral flow immunoassay (LFA) detecting anti-SARS-CoV-2 spike (S)-receptor binding domain (RBD) neutralising antibodies (Healgen SARS-CoV-2 neutralising Antibody Rapid Test Cassette) was compared to the Roche Elecsys/-S anti-SARS-CoV-2 antibody assays and an in vitro surrogate neutralisation assay. A correlation between anti-spike (S), anti-nucleocapsid (N) titres, and in vitro neutralisation was also assessed. Results: 1,777 serology samples were tested using Roche Elecsys/-S anti-SARS-CoV-2 assays to detect total anti-N/S antibodies. 1,562 samples were tested using the POC LFA (including 50 negative controls), and 90 samples were tested using an in vitro ACE2-RBD binding inhibition surrogate neutralisation assay. The POCT demonstrated 97.7% sensitivity, 100% specificity, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 61% in comparison to the commercial assay. Anti-S antibody titres determined by the Roche assay stratified by the POC LFA result groups demonstrated statistically significant differences between the "Positive" and "Negative" LFA groups (p < 0.0001) and the "Weak Positive" and "Positive" LFA groups (p < 0.0001). No statistically significant difference in ACE2-RBD binding inhibition was demonstrated when stratified by the LFA POC results. A positive, statistically significant correlation was demonstrated between the in vitro pseudo-neutralisation assay results and anti-S antibody titres (rho 0.423, p < 0.001) and anti-N antibody titres (rho = 0.55, p < 0.0001). Conclusion: High sensitivity, specificity, and PPV were demonstrated for the POC LFA for the detection of anti-S-RBD antibodies in comparison to the commercial assay. The LFA was not a reliable determinant of the neutralisation capacity of identified antibodies. POC LFA are useful tools in sero-epidemiology settings, pandemic preparedness and may act as supportive tools in treatment decisions through the rapid identification of anti-Spike antibodies.

SARS-CoV-2 epidemiology, antibody dynamics, and neutralisation capacity in Irish healthcare workers in the era of booster COVID-19 vaccinations.

Background: The PRECISE Study, a multi-phase cross-sectional seroprevalence study of anti-SARS-CoV-2 antibodies in Irish healthcare workers (HCW) investigated: (1) risk factors for SARS-CoV-2 seropositivity, (2) the durability of antibody responses in a highly vaccinated HCW cohort, and (3) the neutralisation capacity of detected antibodies, prior to booster COVID-19 vaccination. Materials and methods: Serology samples were collected across two hospital sites in November 2021 and analysed using the Roche Elecsys Anti-SARS-CoV-2/Elecsys-S Anti-SARS-CoV-2 assays to detect anti-nucleocapsid (N) and anti-spike (S) antibodies respectively. Paired serology results from prior study phases were used to analyse changes in individual HCW serostatus over time. Risk-factors for SARS-CoV-2 infection were assessed for demographic and work-related factors. Antibody neutralisation capacity was assessed in a subset of samples via an in vitro ACE2 binding enzyme-linked immunosorbent assay. Results: 2,344 HCW samples were analysed. Median age was 43 years (IQR 33-50) with 80.5% (n = 1,886) female participants. Irish (78.9%, n = 1,850) and Asian (12.3%, n = 288) were the most commonly reported ethnicities. Nursing/midwifery (39.3%, n = 922) was the most common job role. 97.7% of participants were fully vaccinated, with Pfizer (81.1%, n = 1,902) and AstraZeneca (16.1%, n = 377) the most common vaccines received. Seroprevalence for anti-SARS-CoV-2 antibodies indicating prior infection was 23.4%, of these 33.6% represented previously undiagnosed infections. All vaccinated participants demonstrated positive anti-S antibodies and in those with paired serology, no individual demonstrated loss of previously positive anti-S status below assay threshold for positivity. Interval loss of anti-N antibody positivity was demonstrated in 8.8% of previously positive participants with paired results. Risk factors for SARS-CoV-2 seropositivity suggestive of previous infection included age 18-29 years (aRR 1.50, 95% CI 1.19-1.90, p < 0.001), India as country of birth (aRR 1.35, 95% CI 1.01-1.73, p = 0.036), lower education level (aRR 1.35, 95% CI 1.11-1.66, p = 0.004) and HCA job role (aRR 2.12, 95% CI 1.51-2.95, p < 0.001). Antibody neutralisation varied significantly by anti-SARS-CoV-2 antibody status, with highest levels noted in those anti-N positive, in particular those with vaccination plus previous SARS-CoV-2 infection. Conclusion: All vaccinated HCWs maintained anti-S positivity prior to COVID-19 booster vaccination, however anti-N positivity was more dynamic over time. Antibody neutralisation capacity was highest in participants with COVID-19 vaccination plus prior SARS-CoV-2 infection.

Can intravenous antifungal therapy be safely used in the outpatient parenteral antimicrobial therapy (OPAT) setting?

Outpatient parenteral antimicrobial therapy (OPAT) is an established treatment option for patients with a variety of infections who require a period of intravenous therapy, are clinically stable, and do not require continuous monitoring. Many patients with fungal infections require prolonged therapy due to resistance or intolerance to oral antifungal agents. Despite the widespread use of OPAT by infection specialists, antifungal agents appear infrequently used in this setting. We suggest that with appropriate patient selection, patients with fungal infections could successfully be treated on OPAT.

Combined real-time PCR and galactomannan surveillance improves diagnosis of invasive aspergillosis in high risk patients with haematological malignancies.

Invasive aspergillosis (IA) is a leading complication of intensive treatment for haematological malignancies. Earlier diagnosis should facilitate effective antifungal therapy and prevent progression to invasive disease, which is often lethal. Polymerase chain reaction (PCR) assays, targeting the 28S and ITS ribosomal gene regions respectively, were evaluated for early detection of Aspergillus DNA and for diagnostic utility in patients receiving treatment in two busy haematopoietic stem cell transplant centres. Patients undergoing intensive chemotherapy, autologous or allogeneic transplant were eligible for inclusion in the study. EDTA blood and serum samples for circulating Aspergillus biomarkers, including galactomannan (GM), were collected twice-weekly on a prospective basis from all study patients who were categorized according to international consensus criteria for defining invasive fungal disease (IFD). Of 278 patients recruited there were 44 probable IA cases and only one proven case. Moderate sensitivity and specificity, poor positive predictive value (50-80%), but good negative predictive value (>80-90%) were common to both PCR assays. Overall biomarker performance could be improved by combining positive results of either PCR assay with GM taken within a 12-d period. The addition of PCR to GM monitoring in high-risk patients with haematological malignancies provides greater diagnostic accuracy in invasive aspergillosis.

Cardiac troponin I concentration is commonly increased in nondialysis patients with CKD: experience with a sensitive assay.

BACKGROUND: Cardiac troponin (cTn) concentrations commonly are increased in patients with chronic kidney disease (CKD) in the absence of an acute coronary syndrome. cTn T (cTnT) concentration reportedly is increased more commonly than cTn I (cTnI). Using a sensitive cTnI assay, we studied cTnI concentrations in predialysis patients with CKD who did not have an acute coronary event. STUDY DESIGN: Observational cohort study. SETTING AND PARTICIPANTS: Nondialysis patients with CKD attending an outpatient clinic. PREDICTOR: Plasma cTnI was measured using the cTnI-Ultra assay (Bayer HealthCare LLC, Diagnostics Division, Tarrytown, NY), the same manufacturer's standard cTnI assay, and a cTnT assay (Roche Diagnostics PLC, East Sussex, UK). OUTCOMES AND MEASUREMENTS: Prevalence of increased cTn concentration, effect of clinical variables on cTnI-Ultra concentration, and independent associations between cTn assays and all-cause mortality by using multiple regression modeling. RESULTS: Plasma cTnI-Ultra concentration exceeded the upper limit of normal in 33% of patients compared with 18% with the cTnI-standard assay and 43% with the cTnT assay. Age, vascular disease, parathyroid hormone concentration, and left ventricular mass, but not kidney function, had independent effects on plasma cTnI-Ultra concentrations. There were 39 deaths during follow-up. Survival was decreased in patients with baseline cTnI-Ultra concentrations of 0.040 ng/mL or greater (54% versus 83%; P < 0.001), cTnI-standard concentrations of 0.07 ng/mL or greater (55% versus 78%; P = 0.02), and cTnT concentrations of 0.01 ng/mL or greater (59% versus 89%; P < 0.001). Only cTnT concentration was an independent predictor of death. LIMITATION: Only all-cause mortality was recorded. CONCLUSION: Using a sensitive assay, we found that the prevalence of increased cTnI concentrations in patients with CKD is similar to that observed for cTnT. cTnT concentration, but not cTnI, was independently associated with death.

Different consequences of ACE2 and SWI5 gene disruptions for virulence of pathogenic and nonpathogenic yeasts.

Mutants of Candida albicans, Candida glabrata, and Saccharomyces cerevisiae with disruptions in the ACE2 gene and C. glabrata and S. cerevisiae swi5 disruption mutants were tested for virulence in a murine challenge model of disseminated yeast infection. All mutants showed a clumping phenotype, but clumping was minimized in challenge inocula by inclusion of chitinase in the growth medium. In animals rendered temporarily neutropenic by cyclophosphamide treatment, the C. glabrata ace2 null mutant was confirmed as hypervirulent: it led to early terminal illness and kidney, brain, and lung fungal burdens substantially and significantly larger than those in controls. The C. glabrata swi5 null mutant did not lead to terminal illness but generated significantly larger brain and lung burdens than those in controls. The C. albicans ace2 null mutant was very slightly attenuated and the S. cerevisiae ace2 and swi5 null mutants were substantially attenuated relative to their parental control strains. The phenotype of aggressive hypervirulence, unique to disruption of the C. glabrata ACE2 gene among the strains tested, was not seen when the C. glabrata ace2 strain was tested in immunologically intact mice. The different effects seen with these mutants rule out the clumping phenotype as the explanation for hypervirulence in the C. glabrata ace2 mutant. The absence of C. glabrata ace2 hypervirulence in healthy mice may be a tool for definitive future study of host-parasite cross talk in microbial opportunism.

Evolution of the MAT locus and its Ho endonuclease in yeast species.

The genetics of the mating-type (MAT) locus have been studied extensively in Saccharomyces cerevisiae, but relatively little is known about how this complex system evolved. We compared the organization of MAT and mating-type-like (MTL) loci in nine species spanning the hemiascomycete phylogenetic tree. We inferred that the system evolved in a two-step process in which silent HMR/HML cassettes appeared, followed by acquisition of the Ho endonuclease from a mobile genetic element. Ho-mediated switching between an active MAT locus and silent cassettes exists only in the Saccharomyces sensu stricto group and their closest relatives: Candida glabrata, Kluyveromyces delphensis, and Saccharomyces castellii. We identified C. glabrata MTL1 as the ortholog of the MAT locus of K. delphensis and show that switching between C. glabrata MTL1a and MTL1alpha genotypes occurs in vivo. The more distantly related species Kluyveromyces lactis has silent cassettes but switches mating type without the aid of Ho endonuclease. Very distantly related species such as Candida albicans and Yarrowia lipolytica do not have silent cassettes. In Pichia angusta, a homothallic species, we found MATalpha2, MATalpha1, and MATa1 genes adjacent to each other on the same chromosome. Although some continuity in the chromosomal location of the MAT locus can be traced throughout hemiascomycete evolution and even to Neurospora, the gene content of the locus has changed with the loss of an HMG domain gene (MATa2) from the MATa idiomorph shortly after HO was recruited.