Publications by authors named "Ömer Fehmi Tabak"

7 Publications

  • Page 1 of 1

Efficacy and safety of an inactivated whole-virion SARS-CoV-2 vaccine (CoronaVac): interim results of a double-blind, randomised, placebo-controlled, phase 3 trial in Turkey.

Lancet 2021 07 8;398(10296):213-222. Epub 2021 Jul 8.

Department of Infectious Diseases and Clinical Microbiology, Hacettepe University School of Medicine, Ankara, Turkey; Hacettepe University Vaccine Institute, Ankara, Turkey.

Background: CoronaVac, an inactivated whole-virion SARS-CoV-2 vaccine, has been shown to be well tolerated with a good safety profile in individuals aged 18 years and older in phase 1/2 trials, and provided a good humoral response against SARS-CoV-2. We present the interim efficacy and safety results of a phase 3 clinical trial of CoronaVac in Turkey.

Methods: This was a double-blind, randomised, placebo-controlled phase 3 trial. Volunteers aged 18-59 years with no history of COVID-19 and with negative PCR and antibody test results for SARS-CoV-2 were enrolled at 24 centres in Turkey. Exclusion criteria included (but were not limited to) immunosuppressive therapy (including steroids) within the past 6 months, bleeding disorders, asplenia, and receipt of any blood products or immunoglobulins within the past 3 months. The K1 cohort consisted of health-care workers (randomised in a 1:1 ratio), and individuals other than health-care workers were also recruited into the K2 cohort (randomised in a 2:1 ratio) using an interactive web response system. The study vaccine was 3 μg inactivated SARS-CoV-2 virion adsorbed to aluminium hydroxide in a 0·5 mL aqueous suspension. Participants received either vaccine or placebo (consisting of all vaccine components except inactivated virus) intramuscularly on days 0 and 14. The primary efficacy outcome was the prevention of PCR-confirmed symptomatic COVID-19 at least 14 days after the second dose in the per protocol population. Safety analyses were done in the intention-to-treat population. This study is registered with ClinicalTrials.gov (NCT04582344) and is active but no longer recruiting.

Findings: Among 11 303 volunteers screened between Sept 14, 2020, and Jan 5, 2021, 10 218 were randomly allocated. After exclusion of four participants from the vaccine group because of protocol deviations, the intention-to-treat group consisted of 10 214 participants (6646 [65·1%] in the vaccine group and 3568 [34·9%] in the placebo group) and the per protocol group consisted of 10 029 participants (6559 [65·4%] and 3470 [34·6%]) who received two doses of vaccine or placebo. During a median follow-up period of 43 days (IQR 36-48), nine cases of PCR-confirmed symptomatic COVID-19 were reported in the vaccine group (31·7 cases [14·6-59·3] per 1000 person-years) and 32 cases were reported in the placebo group (192·3 cases [135·7-261·1] per 1000 person-years) 14 days or more after the second dose, yielding a vaccine efficacy of 83·5% (95% CI 65·4-92·1; p<0·0001). The frequencies of any adverse events were 1259 (18·9%) in the vaccine group and 603 (16·9%) in the placebo group (p=0·0108) with no fatalities or grade 4 adverse events. The most common systemic adverse event was fatigue (546 [8·2%] participants in the vaccine group and 248 [7·0%] the placebo group, p=0·0228). Injection-site pain was the most frequent local adverse event (157 [2·4%] in the vaccine group and 40 [1·1%] in the placebo group, p<0·0001).

Interpretation: CoronaVac has high efficacy against PCR-confirmed symptomatic COVID-19 with a good safety and tolerability profile.

Funding: Turkish Health Institutes Association.
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http://dx.doi.org/10.1016/S0140-6736(21)01429-XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8266301PMC
July 2021

Clinical and microbiological characteristics of Aeromonas bacteremia in Turkey.

Acta Microbiol Immunol Hung 2021 Jun 16. Epub 2021 Jun 16.

5Department of Infectious Disease, Medical School of Cerrahpasa, Istanbul University, İstanbul, Turkey.

We investigated the cases with Aeromonas bacteremia in terms of clinical and microbiological characteristics, underlying disease and mortality rates. Patients with positive blood cultures were included in this research. Aeromonas bacteremia was diagnosed as at least one positive blood culture for Aeromonas species. The bacteremia was defined as community origin if the onset was in the community or within 72 hours of hospital admission. The others were considered as nosocomial. All bacteria were defined as Aeromonas with conventional method. Species identification was verified by VITEK system. Antibiotic susceptibility tests were analyzed with the disc diffusion, E-test method or VITEK system. Thirty-three patients were diagnosed with bacteremia due to Aeromonas spp. Hematologic and solid tumors were the leading underlying conditions, followed by cirrhosis. Two patients (6%) had community-acquired infections. Aeromonas hydrophila was the most common isolated bacterium. The crude mortality rate was 36%. 12 patients died and 6 deaths and 4 deaths were detected in patients with bacteremia caused by A. hydrophila and Aeromonas sobria respectively. All strains were resistant to ampicillin and more than 90% of the strains were susceptible to trimethoprim-sulfamethoxazole, fluoroquinolone, third generation cephalosporins, and carbapenems. Aeromonas sp. is not a frequent cause of bacteremia however, it may lead to high mortality rates, especially in the immunocompromised hosts and patients with liver cirrhosis. Nosocomial Aeromonas bacteremia is not uncommon in these populations. Broad-spectrum cephalosporins, piperacillin-tazobactam, fluoroquinolones, and carbapenems remain as effective antimicrobial agents for therapy of Aeromonas bacteremia.
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http://dx.doi.org/10.1556/030.2021.01449DOI Listing
June 2021

The role of quantitative HBsAg in patients with HBV DNA between 2000-20,000 IU/ml.

Wien Klin Wochenschr 2021 Jul 29;133(13-14):647-653. Epub 2021 Apr 29.

Department of Infectious Disease, Medical School of Cerrahpasa, Istanbul University-Cerrahpasa, Istanbul, Turkey.

Aims: We aimed to determine the contribution of quantitative HBsAg in differentiating chronic infections from chronic hepatitis in HBeAg negative patients with HBV DNA 2000-20,000 IU/ml.

Material And Methods: A total of 79 untreated HBeAg negative patients were included. Patients were divided into 3 groups based on HBV DNA levels: group 1 (HBV DNA ≤ 2000 IU/ml), group 2 (HBV DNA: 2000-20,000 IU/ml) and group 3 (HBV DNA > 20,000 IU/ml). We collected serum from all patients for quantitative HBsAg analysis. We compared serum quantitative HBsAg levels with biochemical parameters, HBV DNA and liver biopsy results.

Results: In this study 46 patients were female and the mean age was 42 years. Serum quantitative HBsAg levels were found to be significantly lower in chronic infections compared with chronic hepatitis. There was a positive correlation between quantitative HBsAg and HBV DNA, ALT (alanine aminotransferase), HAI score (histological activity index), fibrosis score and disease stage. The cut-off level of quantitative HBsAg was determined as 4425 IU/ml to differentiate chronic infection from chronic hepatitis. With the test specificity of 95%, we found quantitative HBsAg cut-off values 1026 IU/ml and 20,346 IU/ml for the diagnosis of chronic infection and chronic hepatitis, respectively.

Conclusion: Our study suggests that the quantitative HBsAg ≤ 1000 IU/ml limit value might be used for the diagnosis of chronic infection not only in HBV DNA ≤ 2000 IU/ml but also in patients with HBV DNA between 2000-20,000 IU/ml. In addition, antiviral treatment could be considered in patients with quantitative HBsAg > 20,000 IU/ml and HBV DNA > 2000 IU/ml without further examinations such as liver biopsy.
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http://dx.doi.org/10.1007/s00508-021-01854-7DOI Listing
July 2021

Risk factors for development of vancomycin-resistant enterococcal bacteremia among VRE colonizers : A retrospective case control study.

Wien Klin Wochenschr 2021 May 10;133(9-10):478-483. Epub 2020 Sep 10.

Department of Infectious Disease, Medical School of Cerrahpasa, Istanbul University, Istanbul, Turkey.

Aims: We aimed to determine the proportion of vancomycin-resistant enterococci (VRE) colonized patients among all inpatients who later developed VRE bacteremia during hospital stay and to identify the risk factors for VRE bacteremia at a tertiary hospital.

Material And Methods: Patients with positive rectal screening or any clinically significant positive culture results for VRE were included in 1‑year follow-up. Colonization with VRE was defined as a positive culture (rectal, stool, urinary) for VRE without infection and VRE bacteremia was defined as positive blood culture if the signs and symptoms were compatible with infection. To determine the risk factors for VRE bacteremia among VRE colonized patients, a retrospective case control study was performed. The two groups were compared in terms of variables previously defined as risk factors in the literature.

Results: Of 947 positive samples, 17 VRE bacteremia were included in the analysis. Cephalosporin use for more than 3 days within 3 months was a significant risk factor for bacteremia (p = 0.008). Prior use of carbapenems was found to be statistically significant for bacteremia (p = 0.007). In multivariate analyses the use of carbapenems and cephalosporins was an independent risk factor for developing bacteremia among VRE colonizers (odds ratio, OR, 6.67; 95% confidence interval, CI, 1.30-34; p = 0.022 and OR 4.32, 95% CI 1.23-15; p = 0.022, respectively).

Conclusion: A VRE colonization in patients receiving broad-spectrum beta-lactam antibiotics including carbapenems and cephalosporins may result in bacteremia. It is possible to keep mortality at very low levels in VRE bacteremia with effective infection control measures, rapid infectious diseases consultation and rational antimicrobial treatment based on current epidemiological data.
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http://dx.doi.org/10.1007/s00508-020-01733-7DOI Listing
May 2021

Characteristics and outcomes of Behçet's syndrome patients with Coronavirus Disease 2019: a case series of 10 patients.

Intern Emerg Med 2020 11 9;15(8):1567-1571. Epub 2020 Jul 9.

Division of Rheumatology, Department of Internal Medicine, Cerrahpasa Medical School, Istanbul University-Cerrahpasa, Istanbul, Turkey.

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http://dx.doi.org/10.1007/s11739-020-02427-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7344029PMC
November 2020

Human immunodeficiency virus and tuberculosis coinfection: clinical features and predictors of mortality

Turk J Med Sci 2018 Jun 14;48(3):503-508. Epub 2018 Jun 14.

Background/aim: This study was undertaken to identify subjects with human immunodeficiency virus and tuberculosis (HIV/TB) coinfection in a group of HIV-positive patients followed at five different healthcare centers, and to determine the demographic and clinical characteristics of these subjects as well as the predictors of mortality. Materials and methods: A database search for subjects with TB coinfection was performed among 1475 HIV-positive adult patients and a total of 66 individuals were identified with HIV/TB coinfection. Results: There were 66 patients (4.5%) with TB coinfection. Twenty-one percent (n = 14) of the patients with TB coinfection died during the study period and these patients had significantly lower baseline CD4 counts at the time of TB diagnosis (P = 0.005). None of the patients with CD4 count of ≥200 cells/mm3 died during follow-up and a low CD4 count at the time of TB diagnosis (<200 cells/ mm3) was associated with poor survival (P = 0.012). However, none of the parameters emerged as significant independent predictors of survival in multivariate analysis. Conclusion: Coexistence of TB and HIV infection is associated with many clinical challenges and a better understanding of patient characteristics as well as the parameters impacting the outcome will improve the quality of care provided for this group of patients.
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http://dx.doi.org/10.3906/sag-1706-76DOI Listing
June 2018

N-acetyl cysteine therapy in acute viral hepatitis.

World J Gastroenterol 2003 Dec;9(12):2698-700

Department of Internal Medicine and Cordiology, Izzet Baysal Medical Faculty, Izzet Baysal University/Bolu, Turkey.

Aim: To investigate the effect of N-acetyl cysteine (NAC) on acute viral hepatitis (AVH).

Methods: We administered 200 mg oral NAC three times daily (600 mg/day) to the study group and placebo capsules to the control group. All patients were hospitalized and diagnosed as AVH. Blood total and direct bilirubin, ALT, AST, alkaline phosphatase, albumin and globulin levels of each patient were measured twice weekly until total bilirubin level dropped under 2 mg/dl, ALT level under 100 U/L, follow up was continued and then the patients were discharged.

Results: A total of 41(13 female and 28 male) AVH patients were included in our study. The period for normalization of ALT and total bilirubin in the study group was 19.7+/-6.9 days and 13.7 +/- 8.5 days respectively. In the control group it was 20.4 +/- 6.5 days and 16.9 +/- 7.8 days respectively (P>0.05).

Conclusion: NAC administration effected neither the time necessary for normalization of ALT and total bilirubin values nor duration of hospitalization, so we could not suggest NAC for the treatment of icteric AVH cases. However, our results have shown that this drug is not harmful to patients with AVH.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4612035PMC
http://dx.doi.org/10.3748/wjg.v9.i12.2698DOI Listing
December 2003
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