Identification of Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infections Among Healthcare Workers at Sultan Qaboos University Hospital, Oman.

Objectives: This study aimed to describe the incidence and features of asymptomatic COVID-19 infections among healthcare workers (HCWs) at a tertiary hospital in Oman. Methods: This cross-sectional study was conducted between August 2020 and February 2021 among HCWs with no history of COVID-19 infection. An online questionnaire collected sociodemographic and clinical data. COVID-19 infection was diagnosed using nasopharyngeal/throat swabs, which were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Analyses were performed using the Chi-squared test, Fisher's exact test or univariate ordinary least squares regression, as appropriate. Results: A total of 583 HCWs participated in the study, most of whom were female (56.6%), and the mean age was 35 ± 8 years. Only 9.6% (95% confidence interval [CI]: 7.3-12.3%) of the HCWs were at high exposure risk as they were directly involved in the care of COVID-19-infected patients. Overall, 4.1% (95% CI: 2.7-6.1%) of the HCWs screened positive for SARS-CoV-2, of which 20.8% developed symptoms within two weeks. The frequency of SARS-CoV-2 positivity among HCWs working in high-, intermediate-, low- and miscellaneous-risk areas was 1.8% (95% CI: <0.1-9.6%), 2.6% (95% CI: <0.1-6.5%), 5.3% (95% CI: 0.3-9.3%) and 4.8% (95% CI: <0.1-69.3%), respectively. Working in high-risk areas was associated with increased compliance with various infection control strategies (P <0.001). Conclusion: There was a greater frequency of SARS-CoV-2 positivity among HCWs working in low-risk areas, whereas HCWs who worked in high-risk areas were significantly more likely to report increased compliance with infection control strategies.

T Cell Depleted Haploidentical Hematopoietic Stem Cell Transplantation for Patients with Familial Hemophagocytic Lymphohistiocytosis Who Do Not Have Matched Family Donors: Experience in Oman.

Familial hemophagocytic lymphohistiocytosis (FHLH) is a potentially fatal disorder of immune regulation. Management includes chemotherapy followed by hematopoietic stem cell transplantation (HSCT). T cell depleted (TCD)-haploidentical HSCT could be an option for those patients who do not have HLA matching family donor. The objective of this study was to report on the outcome of TCD-haploidentical HSCT in patients with FHLH who underwent transplantation at Sultan Qaboos University Hospital (SQUH). This is a retrospective report on 12 patients with FHLH who received TCD- haploidentical HSCT at SQUH between August 2010 and December 2018. Epidemiologic characteristics and details on the transplantation procedures and complications were collected from patients' electronic records. Twelve patients with FHLH received TCD-haploidentical HSCT after a myeloablative conditioning regimen composed of treosulfan/thiotepa/fludarabine/anti-thymocyte globulin and rituximab. The mean age at transplantation was 11.67 ± 8 months. All patients had Perforin gene mutations, except 1 patient who had an UNC-13D mutation. Most patients received TCRαß+/CD19+ depleted grafts for faster immune reconstitution. Seven patients (58.3%) have been cured with a mean follow-up duration of 3.44 years. Four patients died of multiorgan failure secondary to gram-negative sepsis. One patient had primary graft failure, and 2 patients had mild graft-versus-host disease. Two patients had Pneumocystis carinii pneumonia, 2 had adenoviremia, and 9 patients had cytomegalovirus (CMV) viremia. Among patients with CMV viremia, 2 had evidence of disease (retinitis, enteritis). All patients with CMV viremia were treated successfully with foscarnet pre-engraftment and ganciclovir postengraftment, respectively. TCD-haploidentical HSCT could be a viable option for patients with FHLH who do not have HLA matching family donors. Infectious complications are the leading cause of death in that setting. CMV viremia was the most frequently encountered infectious complication.

The reliability of HBV core antibody in serological screening for hepatitis B virus.

INTRODUCTION: Accurate diagnosis of hepatitis B virus (HBV) infection is essential for infection control, treatment and screening of potential blood, organ and tissue donors. We assessed the sensitivity of the HBsAg and HBcAb as screening assays alone and in combination for detecting HBV infection in a series of Australian patients. The performance of the Architect (Abbott Diagnostics, Germany) and the Elecsys (Roche Diagnostics, Germany) platforms were assessed for detection of HBcAb. METHODS: There were 2778 blood samples assessed using the COBAS Ampliprep/TaqMan test for HBV DNA, of which 331 sera had concurrent HBV serology testing. This allowed determination of the correlation between HBV DNA and different serological markers. Of the 331 sera, 260 had sufficient residual volume to be retested for HBcAb using both Elecsys and the Architect assays. RESULTS: Of the 331 patients, one (0.3%) was negative by the Architect Anti-HBc II assay, in the presence of HBV DNA and positive HBsAg, consistent with recent infection. Positive HBcAb in the absence of HBV DNA was found in 67 of 331 (20.2%) patients. Of these, 18 of 67 had isolated HBcAb with negative results on all other tests, with 12 of 18 (3.6%) demonstrating low HBcAb signals on chemiluminscent microparticle assay. No cases of detectable HBV DNA in the presence of negative serology were found. When the HBcAb was used as a marker for past exposure or chronic HBV infection, the Architect Anti-HBc II assay demonstrated sensitivity and specificity of 98% and 79.9%, respectively, compared to 90% and 78.9%, respectively, for the Elecsys Anti-HBc assay. The combination of the Architect Anti-HBc II and HBsAg assays, as per conventional solid organ donor and recipient screening protocols, had 90% specificity and 100% sensitivity for determining HBV infection. CONCLUSION: This study shows that the use of combined HBsAg and HBcAb is sensitive and reliable for screening and predicting HBV nucleic acid test (NAT) positivity, whereas HBcAb alone missed an acute infection in this study population. There were no significant differences detectable between the Architect and the Elecsys HBcAb assays (p=0.001), suggesting laboratories should assess individual assays in the local population before use as screening tests.

Hendra virus: a one health tale of flying foxes, horses and humans.

Hendra virus, a member of the family Paramyxoviridae, was first recognized following a devastating outbreak in Queensland, Australia, in 1994. The naturally acquired symptomatic infection, characterized by a rapidly progressive illness involving the respiratory system and/or CNS, has so far only been recognized in horses and humans. However, there is potential for other species to be infected, with significant consequences for animal and human health. Prevention of infection involves efforts to interrupt the bat-to-horse and horse-to-human transmission interfaces. Education and infection-control efforts remain the key to reducing risk of transmission, particularly as no effective antiviral treatment is currently available. The recent release of an equine Hendra G glycoprotein subunit vaccine is an exciting advance that offers the opportunity to curb the recent increase in equine transmission events occurring in endemic coastal regions of Australia and thereby reduce the risk of infection in humans.