Outcome after single dose of ChAdOx1 vaccine against SARS-CoV-2 infection at 16 weeks post-vaccination among healthy adults in Saudi Arabia.

BACKGROUND: The rate of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection and immunogenicity of a single dose of ChAdOx1 vaccine at 16 weeks post-vaccination among young and healthy participants remains unclear in Saudi Arabia. OBJECTIVES: Assess the rate of subsequent infection and immunogenicity of a single dose of ChAdOx1 vaccine at 16 weeks post-vaccination in a sample of healthy and young participants. DESIGN: Cross-sectional study SETTING: Academic teaching hospital in Riyadh, Saudi Arabia SUBJECTS AND METHODS: Healthy participants 18-50 years of age, who received one dose of ChAdOx1 vaccine and had no history of SARS CoV-2 infection were recruited, and blood samples were obtained 16 weeks after vaccination to assess immunogenicity using a commercially available kit. MAIN OUTCOME MEASURES: The rate of SARS-CoV-2 infection within 16 weeks post-vaccination. SAMPLE SIZE: 385 participants with median (IQR) age of 34 (29-38) years. RESULTS: Eleven (2.8%) participants acquired polymerase chain reaction (PCR)-confirmed infection within 16 weeks after a single dose of ChAdOx1 vaccine (mean [SD] 42.5 [28] days post-vaccination). No hospital or intensive care unit admissions occurred among the subjects in this sample. Females were significantly over-represented in PCR-confirmed cases of SARS-CoV-2 infection, with 10 of 11 infections occurring in females (P=.006). Antibody response against anti-spike IgG were detectable in 92.7% of subjects at 16 weeks' post-vaccination. The median anti-spike IgG level after vaccination was 273.1 (IQR 107-1052 AU/mL). However, the anti-nucleocapsid IgG antibody demonstrated a sensitivity of only 20%. CONCLUSION: A single dose of ChAdOx1 vaccine in healthy and young individuals was associated with a low, single-digit rate of PCR-confirmed infection, most of which were mild. LIMITATIONS: Small sample size and single-center. CONFLICT OF INTEREST: None.

Preventing SARS-CoV-2 transmission in the emergency department by implementing a separate pathway for patients with respiratory conditions.

OBJECTIVES: This study aimed to describe the development and implementation of a separated pathway to check and treat patients with a suspected/confirmed coronavirus disease 2019 (COVID-19) in the emergency department (ED) at King Abdullah bin Abdulaziz University Hospital in Riyadh. METHODS: We conducted a retrospective, descriptive longitudinal study from March to July 2020 by analyzing data of all confirmed cases of COVID-19 among ED visitors and healthcare workers in King Abdullah bin Abdulaziz University Hospital. RESULTS: During the study period, a total of 1,182 swab samples were collected for testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), of which 285 (24.1%) tested positive. Of the 285 cases of confirmed SARS-CoV-2 infection, 18 were healthcare workers and 267 were patients. As a result of using the respiratory pathway for COVID-19 patients, the hospital managed to limit transmission of SARS-CoV-2 not only between patients but also between patients and healthcare workers, while also containing the pandemic. There were no cases of nosocomial SARS-CoV-2 infection recorded among the patients who visited the ED or the flu clinic. All confirmed cases were community acquired and patients were cared for under constrained measures. CONCLUSIONS: Implementing infection control measures and restricting those with respiratory symptoms to the ED pathway prevented nosocomial spread of SARS-CoV-2 infection in the ED.

The use of neutrophil-to-lymphocyte ratio (NLR) as a marker for COVID-19 infection in Saudi Arabia: A case-control retrospective multicenter study.

OBJECTIVES: To assess the neutrophil-to-lymphocyte ratio (NLR) diagnostic and prognostic value in the context of Coronavirus disease-2019 (COVID-19) infection in Saudi Arabia. METHODS: A case-control study in which 701 confirmed COVID-19 patients (of which 41 were intensive care unit [ICU]-admitted) and 250 control subjects were enrolled. The study was conducted retrospectively in October on patients admitted to 3 separate hospitals in Saudi Arabia namely: King Abdullah Bin Abdulaziz University Hospital (Riyadh), Ohud Hospital (Madinah), and Nojood Medical Center (Madinah) between May and September 2020. Neutrophil-to-lymphocyte ratio was calculated based on absolute neutrophil and lymphocyte count. Institutional ethical approval was obtained prior to the study. RESULTS: Patients (median age 35 years), of which 54.8% were females, were younger than the control cohort (median age 48 years). Patients had significantly higher NLR compared to the control group. Intensive care unit admitted patients had significantly higher platelet, WBC and neutrophil counts. The ICU patients' NLR was almost twice as of the non-intensive patients. The NLR value of 5.5 was found to be of high specificity (96.4%) and positive predictive value (91.4%) in diagnosing COVID-19. Furthermore, it had a very good sensitivity (86.4%) in predicting severe forms of disease, such as, ICU admission. CONCLUSION: Neutrophil-to-lymphocyte ratio is an important tool in determining the COVID-19 clinical status. This study further confirms the prognostic value of NLR in detecting severe infection, and those patients with high NLR should be closely monitored and managed.

A Comparative Study of Clinical Presentation and Risk Factors for Adverse Outcome in Patients Hospitalised with Acute Respiratory Disease Due to MERS Coronavirus or Other Causes.

Middle East Respiratory syndrome (MERS) first emerged in Saudi Arabia in 2012 and remains a global health concern. The objective of this study was to compare the clinical features and risk factors for adverse outcome in patients with RT-PCR confirmed MERS and in those with acute respiratory disease who were MERS-CoV negative, presenting to the King Fahad Medical City (KFMC) in Riyadh between October 2012 and May 2014. The demographics, clinical and laboratory characteristics and clinical outcomes of patients with RT-PCR confirmed MERS-CoV infection was compared with those testing negative MERS-CoV PCR. Health care workers (HCW) with MERS were compared with MERS patients who were not health care workers. One hundred and fifty nine patients were eligible for inclusion. Forty eight tested positive for MERS CoV, 44 (92%) being hospital acquired infections and 23 were HCW. There were 111 MERS-CoV negative patients with acute respiratory illnesses included in this study as "negative controls". Patient with confirmed MERS-CoV infection were not clinically distinguishable from those with negative MERS-CoV RT-PCR results although diarrhoea was commoner in MERS patients. A high level of suspicion in initiating laboratory tests for MERS-CoV is therefore indicated. Variables associated with adverse outcome were older age and diabetes as a co-morbid illness. Interestingly, co-morbid illnesses other than diabetes were not significantly associated with poor outcome. Health care workers with MERS had a markedly better clinical outcome compared to non HCW MERS patients.

In vitro evaluation of efficacy of different rotary instrument systems for gutta percha removal during root canal retreatment.

BACKGROUND: Complete removal of old filling material during root canal retreatment is fundamental for predictable cleaning and shaping of canal anatomy. Most of the retreatment methods tested in earlier studies have shown inability to achieve complete removal of root canal filling. Therefore the aim of this investigation was to assess the efficacy of three different rotary nickel titanium retreatment systems and Hedstrom files in removing filling material from root canals. MATERIAL AND METHODS: Sixty extracted mandibular premolars were decoronated to leave 15 mm root. Specimen were hand instrumented and obturated using gutta percha and AH plus root canal sealer. After storage period of two weeks, roots were retreated with three (Protaper retreatment files, Mtwo retreatment files, NRT GPR) rotary retreatment instrument systems and Hedstroem files. Subsequently, samples were sectioned longitudinally and examined under stereomicroscope. Digital images were recorded and evaluated using Digital Image Analysing Software. The retreatment time was recorded for each tooth using a stopwatch. The area of canal and the residual filling material was recorded in mm2 and the percentage of remaining filling material on canal walls was calculated. Data was analysed using ANOVA test. RESULTS: Significantly less amount of residual filling material was present in protaper and Mtwo instrumented teeth (p < 0.05) compared to NRT GPR and Hedstrom files group. Protaper instruments also required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. CONCLUSIONS: None of the instruments were able to remove the filling material completely from root canal. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files. Key words:Gutta-percha removal, nickel titanium, root canal retreatment, rotary instruments.

Molecular Epidemiology of Hospital Outbreak of Middle East Respiratory Syndrome, Riyadh, Saudi Arabia, 2014.

We investigated an outbreak of Middle East respiratory syndrome (MERS) at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, during March 29-May 21, 2014. This outbreak involved 45 patients: 8 infected outside KFMC, 13 long-term patients at KFMC, 23 health care workers, and 1 who had an indeterminate source of infection. Sequences of full-length MERS coronavirus (MERS-CoV) from 10 patients and a partial sequence of MERS-CoV from another patient, when compared with other MERS-CoV sequences, demonstrated that this outbreak was part of a larger outbreak that affected multiple health care facilities in Riyadh and possibly arose from a single zoonotic transmission event that occurred in December 2013 (95% highest posterior density interval November 8, 2013-February 10, 2014). This finding suggested continued health care-associated transmission for 5 months. Molecular epidemiology documented multiple external introductions in a seemingly contiguous outbreak and helped support or refute transmission pathways suspected through epidemiologic investigation.