Hacettepe health cohort (HU-CoVaCS): study design, baseline characteristics and the first 3-month-follow up of COVID-19 vaccinated students

Objective: This study included participants from Hacettepe University 4th, 5th, and 6th-grade students of Medical School and 4th and 5th-grade students of Dental School;and aimed to evaluate the general health status, COVID-19 history, vaccination status, and SARS-CoV-2 antibody levels of the participants to support their physical and social health, during the pandemic period. Methods: A prospective cohort study was conducted with an integrated, matched, nested case-control study. Sociodemographic characteristics, life habits, COVID-19 history, vaccination status, compliance with mask-distance-hygiene rules, and risks (if any) for COVID-19 were inquired via online questionnaires. Physical examinations, complete blood count, biochemistry tests, and anti-SARS-CoV-2 anti-spike antibody tests were conducted for all consenting participants. All analyses were established using depersonalized data. Results: Of the 778 participants completing the baseline visit in June-July 2021, the percentages of those vaccinated with at least one, two, and three/more doses of COVID-19 vaccine were 99.1%, 98.0%, and 11.7%, respectively;one had four doses. The median (minimum-maximum) time since the last vaccination was 134 (34-166) days for those vaccinated with two doses [CoronaVac (Sinovac Life Sciences, Beijing, China)] and 25 (14-56) days for those vaccinated with three doses [two doses of CoronaVac and a last dose of Pfizer-BioNTech mRNA vaccine (ComirnatyR). The third dose was applied at a median of 164 (151-202) days after the second dose, and all were heterologous in type. The median (minimum-maximum) antibody level for the overall group was 53.55(0-5680) BAU/mL: 47.19 BAU/mL in those who received two doses, with a more than 100 times increase after a third dose (4943.64 BAU/mL). Of the 522 participants followed up to October 1, 2021, 6 PCR-positive symptomatic participants were diagnosed with COVID-19: the incidence rate was 4/1000 person-months. Conclusion: A 100-fold neutralizing antibody level following the third dose demonstrated the importance of a booster dose. Given the time lag between doses, antibody measurements of BioNTech recipients should be repeated in the upcoming months. Booster selection should involve antibody level, variant sensitivity of the vaccine, and individual characteristics of the recipient.

Methodological Issues in COVID-19-Related Publications During the Pandemic

SARS-CoV-2 has led to a global public health problem with its quick spread in a naive population, devastatingly affect-ing social and economic lives. The most positive effect of the pandemic has been on the novel, from bench-to-bedside scientific research, methodology, and publications. The unprecedented speed in planning, conducting, and reporting research activities has improved patient care and public policies during the pandemic. However, some overlooked methodological concerns have hindered the intrinsic and extrinsic validity of the publications. This study, based on peer-reviewed medical journals over the pandemic, aimed to increase awareness of common methodological issues that may improve the quality of evidence upon correction.

Hacettepe Health Cohort (HU-CoVaCS): Study Design, Baseline Characteristics and the First 3-Month-Follow Up of COVID-19 Vaccinated Students.

Objective: This study included participants from Hacettepe University 4th, 5th, and 6th-grade students of Medical School and 4th and 5th-grade students of Dental School;and aimed to evaluate the general health status, COVID-19 history, vaccination status, and SARS-CoV-2 antibody levels of the participants to support their physical and social health, during the pandemic period. Method(s): A prospective cohort study was conducted with an integrated, matched, nested case-control study. Sociode-mographic characteristics, life habits, COVID-19 history, vaccination status, compliance with mask-distance-hygiene rules, and risks (if any) for COVID-19 were inquired via online questionnaires. Physical examinations, complete blood count, biochemistry tests, and anti-SARS-CoV-2 anti-spike antibody tests were conducted for all consenting partici-pants. All analyses were established using depersonalized data. Result(s): Of the 778 participants completing the baseline visit in June-July 2021, the percentages of those vaccinated with at least one, two, and three/more doses of COVID-19 vaccine were 99.1%, 98.0%, and 11.7%, respectively;one had four doses. The median (minimum-maximum) time since the last vaccination was 134 (34-166) days for those vaccinated with two doses [CoronaVac (Sinovac Life Sciences, Beijing, China)] and 25 (14-56) days for those vaccinated with three doses [two doses of CoronaVac and a last dose of Pfizer-BioNTech mRNA vaccine (Comirnaty). The third dose was applied at a median of 164 (151-202) days after the second dose, and all were heterologous in type. The median (minimum-maximum) antibody level for the overall group was 53.55(0-5680) BAU/mL: 47.19 BAU/mL in those who received two doses, with a more than 100 times increase after a third dose (4943.64 BAU/mL). Of the 522 participants followed up to October 1, 2021, 6 PCR-positive symptomatic participants were diagnosed with COVID-19: the incidence rate was 4/1000 person-months. Conclusion(s): A 100-fold neutralizing antibody level following the third dose demonstrated the importance of a booster dose. Given the time lag between doses, antibody measurements of BioNTech recipients should be repeated in the upcoming months. Booster selection should involve antibody level, variant sensitivity of the vaccine, and individual characteristics of the recipient.Copyright © 2023, DOC Design and Informatics Co. Ltd.. All rights reserved.

Memory T cell responses in seronegative older adults following SARS-CoV-2 vaccination

Generating memory T cell responses besides humoral immune responses is essential when it comes to the efficacy of a vaccine. In this study, the presence of memory T cell responses after aluminum-adjuvanted inactivated whole-virion SARS-CoV-2 vaccine (CoronaVac) in seronegative and seropositive elderly individuals were examined. CD4+ and CD8+ memory T cell proliferation and IFN-gamma production capacities were evaluated. Additionally, clinical frailty scale (CFS) and FRAIL scales of the individuals were scored. CD4+ memory T cell responses more prominent than CD8+ memory T cells. In seronegative individuals, 80% of them had memory CD4+ and IFN-gamma, whereas 50% of them had memory CD4+ and all of them had IFN-gamma responses. Additionally, 40% of seronegative patients and 50% of seropositive patients had memory CD8+ responses. To sum up, humoral immune responses are not associated with memory T cell responses, and in seronegative individuals, memory T cell responses can be detected.Copyright © 2022

Back to the First Days of the Pandemic: How Well Have We Done to Diagnose COVID-19 in Healthcare Workers?

Introduction: Healthcare workers (HCWs) are one of the most vulnerable groups for COVID-19. SARS-CoV-2 PCR was offered to HCWs who had symptoms compatible with COVID-19 or who had a close contact with COVID-19 patient. A rapid antibody test was used to identify the risk of exposure of the HCWs who worked at high-risk units in our hospital during the first month of the pandemic. Herein, we aimed to evaluate the usefulness of this approach. Materials and Methods: The records of the HCWs from a university hospital who were tested by SARS-CoV-2 PCR or rapid antibody test between March 12, 2020 and April 04, 2020 were reviewed retrospectively. Demographic and clinical characteristics of HCWs were extracted from the electronic database. Wards or outpatient clinics that served COVID-19 patients were defined as high-risk units. Results: A total of 599 HCWs were tested for SARS-CoV-2 by PCR and 409 by rapid antibody test. Thirty-seven (6.2%) were found to be PCR positive. Eleven (29.7%) out of 37 HCWs were asymptomatic when they were tested. There was no statistically significant relationship between PCR positivity and occupation or working unit. A positive PCR result was detected in 24 HCWs during the first admission. Eleven out of 114 HCWs who were tested by a second PCR were found to be positive and two out of 17 HCWs who were tested by a third test were reported as PCR positive. Median interval between the first and second PCR was seven days (IQR= 8.5 days) and median interval between second and third PCR test was 4.5 days for the HCWs who were reported as positive at repeated PCR tests. Rapid antibody test was positive in one HCW who did not have a history of COVID-19. Conclusion: Approximately, one third of the SARS-CoV-2 PCR positive HCWs were asymptomatic. In case of increasing incidence of COVID-19 in the community, a regular screening policy for the HCWs regardless of their occupation and contact tracing might help to have a safe environment in hospitals. Screening policy should be based on well validated tests.

COVID-19 and Children: From an Epidemiological Perspective

COVID-19, caused by SARS-CoV-2, has rapidly progressed globally started from early days of 2020 and was disseminated to 187 countries and territories by April. As of May 3, 2020, COVID-19 has led to a total of 3,507,442 cases and 245,241 related deaths, globally. Turkey, was successful to delay the first COVID-19 case until March 10, yet, case numbers increased fast, reaching to the top 7th rank in the list of countries with the highest case numbers. It is fortunate that the case-fatality ratio was relatively low, with a somewhat stable course around 2.5%. Somewhat stable course of new case numbers, with an apparent decrease through the end of April led to onset of normalization attempts in the country. The future course of the pandemic will be mainly determined by compliance of the general public with personal hygiene, mask use and social distancing. Globally, COVID-19-related morbidity and mortality rates are lower among children than in adults. Underlying mechanisms for this difference has not been clarified, yet, may be linked to lower exposure rates among children, their immune response may be different and/or higher rates of asymptomatic cases may have lower admissions/testing among children. However, it is important to emphasize that children are prone to SARS-CoV-2, too and all relevant preventions should be ensured. This issue should also be considered in evaluating potential risk of infection transfer from asymptomatic youngsters to the elderly and/or to those with chronic diseases. Data on COVID-19-related case numbers and deaths in Turkey have not been published so far for children. This requires urgent consideration for related reporting and novel research activities on health burden of COVID-19 on Turkish children. Success in combating the COVID-19 pandemic requires concurrent efforts for clinical management of patients together with epidemiological studies of available national data and establishment of specific research to provide evidence for national and international preventive interventions. Learnings from this pandemic will provide direct evidence for management of future pandemics, and all related parties should be motivated to prepare detailed reporting of ongoing efforts and their outputs.

Methodological Issues in COVID-19-Related Publications During the Pandemic.

SARS-CoV-2 has led to a global public health problem with its quick spread in a naive population, devastatingly affect-ing social and economic lives. The most positive effect of the pandemic has been on the novel, from bench-to-bedside scientific research, methodology, and publications. The unprecedented speed in planning, conducting, and reporting research activities has improved patient care and public policies during the pandemic. However, some overlooked methodological concerns have hindered the intrinsic and extrinsic validity of the publications. This study, based on peer-reviewed medical journals over the pandemic, aimed to increase awareness of common methodological issues that may improve the quality of evidence upon correction. Copyright © 2022, DOC Design and Informatics Co. Ltd.. All rights reserved.

Methodological Issues in COVID-19-Related Publications During the Pandemic

SARS-CoV-2 has led to a global public health problem with its quick spread in a naive population, devastatingly affect-ing social and economic lives. The most positive effect of the pandemic has been on the novel, from bench-to-bedside scientific research, methodology, and publications. The unprecedented speed in planning, conducting, and reporting research activities has improved patient care and public policies during the pandemic. However, some overlooked methodological concerns have hindered the intrinsic and extrinsic validity of the publications. This study, based on peer-reviewed medical journals over the pandemic, aimed to increase awareness of common methodological issues that may improve the quality of evidence upon correction. Copyright © 2022, DOC Design and Informatics Co. Ltd.. All rights reserved.

Are neutrophil-to-lymphocyte ratios and large unstained cells different in hospitalized COVID-19 PCR-positive patients with and without diabetes mellitus?

OBJECTIVE: SARS-CoV-2 might present with multisystem involvement due to its entry into many cells with ACE2 receptors on their surfaces, such as heart, endothelial, and lung alveoli cells. Studies have indicated that COVID-19 infection causes a severe clinical presentation in diabetic patients due to dysregulation of the metabolic and immune systems. The hematological effects of COVID-19 and the relationship of lymphopenia with the severity of the disease have been reported previously. The parameter of percentage of large unstained cells (LUCs) reflects active lymphocytes and peroxidase-negative cells. The neutrophil-to-lymphocyte ratio (NLR) is another reliable marker of inflammation in cases of cardiac diseases, solid tumors, and sepsis. The present study aimed to evaluate whether the parameters of LUCs and NLR differed between diabetic and nondiabetic individuals with COVID-19. Associations with disease severity were also sought. MATERIALS AND METHODS: In our retrospective study, the data of 1,053 patients [230 diabetic patients (21.83%) and 823 nondiabetic patients (78.15%)] were reviewed. The white blood cell (WBC) count, neutrophil count, neutrophil%, lymphocyte count, lymphocyte%, LUC count, %LUCs, NLR, platelet count, hemoglobin level, HbA1c, history of diabetes, surveillance during hospitalization, and pulmonary infiltration status within the first 24 hours after admission to the hospital were analyzed from the records. RESULTS: When diabetic patients were compared with nondiabetics, the age [65 (20-90) vs. 42 (18-94) years], WBC count [6.72 (2.6-24.04) vs.  5.91 (1.35-52.68)], neutrophil count [4.29 (1.28-65) vs. 3.68 (0.02-50.47)], neutrophil% [67.53±12.3 vs.  64.08±13.28], NLR [3.35 (0.83-38.11) vs. 2.48 (0.01-68.58)], and LUC count [0.11 (0.03-0.98) vs. 0.1 (0.02-3.06)] of the diabetic group were found to be higher and these differences were statistically significant (p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, and p=0.015, respectively). CONCLUSIONS: We determined that LUC counts and NLR values in COVID-19-positive patients with diabetes were statistically significantly higher compared to nondiabetic patients.

Neutralizing antibody response and associated factors in Coronavirus-19 disease (COVID-19) up to one month

Background: There is a knowledge gap about the characteristics of neutralizing antibody (NAb) response in patients who recovered COVID-19. In this study, it is aimed to elucidate the factors affecting the presence and titers of antibodies up to 30-days after onset. Material and methods: A total of 129 laboratory-confirmed COVID-19 patients were enrolled. Clinical data were obtained retrospectively. SARS-CoV-2 specific NAb, IgM, and IgG antibody responses were analyzed. Results: SARS-CoV-2 specific NAb, IgM and IgG, were detected at the time of hospital discharge in 60.5%, 30.2%, and 51.9% of the patients, respectively. The median time for obtaining serum samples for antibody tests after symptoms' onset was 11 days. The median titer of neutralizing antibody (SN50) was significantly higher in severe patients (25 vs. 7.5, p=0.009). Of the 23 severe patients, 52.2% (n=12) had higher NAb titers (i.e., SN50≥1:25) when compared to that in non-severe patients (OR=2.89;95%CI=1.15-7.28, p=0.021), yet, the potential effect of follow-up time on NAb status and titers could not be ruled out. Conclusions: The presence of antibody response is not the only determinative factor for recovery. The presence and higher titers of NAb were detected more in severe patients than their non-severe counterparts. Survival analysis suggested that this difference could at least be partially explained by the length of follow-up through antibody testing (at discharge) after symptoms' onset. © 2022 Aliye Bastug et al.