One-Year Post-Vaccination Longitudinal Follow-Up of Quantitative SARS-CoV-2 Anti-Spike Total Antibodies in Health Care Professionals and Evaluation of Correlation with Surrogate Neutralization Test.

Numerous vaccines have been generated to decrease the morbidity and mortality of COVID-19. This study aims to evaluate the immunogenicity of the heterologous boosts by BioNTech against homologous boosts by CoronaVac at three-month intervals in two health care worker (HCW) cohorts, with or without prior COVID-19, for one year post-vaccination. This is a prospective cohort study in which the humoral responses of 386 HCWs were followed-up longitudinally in six main groups according to their previous COVID-19 exposure and vaccination status. Anti-SARS-CoV-2 spike-RBD total antibody levels were measured and SARS-CoV-2 neutralization antibody (NAbs) responses against the ancestral Wuhan and the Omicron variant were evaluated comparatively using international standard serum for Wuhan and Omicron, as well as with the aid of a conversion tool. The anti-SARS-CoV-2 spike-RBD total Ab and Nab difference between with and without prior COVID-19, three months after two-dose primary vaccination with CoronaVac, was statistically significant (p = 0.001). In the subsequent follow-ups, this difference was not observed between the groups. Those previously infected (PI) and non-previously infected (NPI) groups receiving BioNTech as the third dose had higher anti-SARS-CoV-2 spike total Ab levels (14.2-fold and 17.4-fold, respectively, p = 0.001) and Nab responses (against Wuhan and Omicron) than those receiving CoronaVac. Ab responses after booster vaccination decreased significantly in all groups at the ninth-month follow-up (p < 0.05); however, Abs were still higher in all booster received groups than that in the primary vaccination. Abs were above the protective level at the twelfth-month measurement in the entire of the second BioNTech received group as the fourth dose of vaccination. In the one-year follow-up period, the increased incidence of COVID-19 in the groups vaccinated with two or three doses of CoronaVac compared with the groups vaccinated with BioNTech as a booster suggested that continuing the heterologous CoronaVac/BioNTech vaccination, revised according to current SARS-CoV-2 variants and with at least a six-month interval booster would be an effective and safe strategy for protection against COVID-19, particularly in health care workers.

Higher antibody responses after mRNA-based vaccine compared to inactivated vaccine against SARS-CoV-2 in Behcet's syndrome.

There are limited data about humoral response to vaccine in Behçet's syndrome (BS). We compared SARS-CoV-2 antibody response after two doses of inactivated (Sinovac/CoronaVac) or mRNA (Pfizer/BioNTech) vaccines in patients with BS and healthy controls (HCs). We studied 166 (92M/74F) patients with BS (mean age: 42.9 ± 9.6 years) and 165 (75M/90F) healthy controls (mean age: 42.4 ± 10.4 years), in a single-center cross-sectional design between April 2021 and October 2021. A total of 80 patients with BS and 89 HCs received two doses of CoronaVac, while 86 patients with BS and 76 HCs were vaccinated with BioNTech. All study subjects had a negative history for COVID-19. Serum samples were collected at least 21 days after the second dose of the vaccine. Anti-spike IgG antibody titers were measured quantitatively using a commercially available immunoassay method. We found that the great majority in both patient and HC groups had detectable antibodies after either CoronaVac (96.3% vs 100%) or BioNTech (98.8% vs 100%). Among those vaccinated with CoronaVac, BS patients had significantly lower median (IQR) titers compared to HCs [36.5 (12.5-128.5) vs 102 (59-180), p < 0.001]. On the other hand, antibody titers did not differ among patients with BS and HCs who were vaccinated with BioNTech [1648.5 (527.0-3693.8) vs 1516.0 (836.3-2599.5), p = 0.512). Among different treatment regimen subgroups in both vaccine groups, those who were using anti-TNF-based treatment had the lowest antibody titers. However, the difference was statistically significant only among those vaccinated with CoronaVac. Among patients vaccinated with BioNTech, there was no statistically significant difference between different treatment regimen groups. Compared to inactivated COVID-19 vaccine, mRNA-based vaccine elicited higher antibody titers among BS patients. Only in the CoronaVac group, patients especially those using anti-TNF agents were found to have low titers compared to healthy subjects. BS patients vaccinated with BioNTech were found to have similar seroconversion rates and antibody levels compared to healthy controls. Further studies should assess whether the low antibody titers are associated with diminished protection against COVID-19 in both vaccine groups.

Detection of SARS-CoV-2 RNA in Upper Respiratory Swap Samples by Pooling Method

Background: Widespread and effective use of molecular diagnostic tests is indispensable for protecting public health and containing the severe respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. More than 1 year into the pandemic, as resources have reached a point of depletion, grouping samples in pools of certain sizes appears to be a reasonable method to reduce both the costs and the processing time without necessitating additional training, equipment, or materials. Aims: To assess whether the pooling strategy that was used in past outbreaks and is used in blood tests prior to transfusion for screening large populations can also be used in SARS CoV-2 tests. Study Design: Diagnostic accuracy study. Methods: This prospective study was conducted with 2815 samples, sent to the coronavirus disease 2019 (COVID-19) Laboratory of our hospital between February 12 and 21, 2021, to be tested for the presence of SARS-CoV-2. The samples were examined individually and in pools of five 100 µl taken from each sequential sample, using 3 different SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) kits, the Allplex™ 2019-nCoV Assay kit (Seegene, Republic of Korea), the GeneMAP™ 2019-nCoV detection V.3 kit (GenMark, Türkiye), and the Bio-Speedy™ SARS-CoV-2 Double Gene™ RT-qPCR kit (Bioeksen, Türkiye) on the BioRAD CFX96™ Touch (Bio-Rad Laboratories Inc., Hercules, CA, USA) platform available in our laboratory. Results: Following the extraction of serial dilutions prepared from the SARS-CoV-2 RNA positive (cycle of threshold: 20) sample, the standard curves of RT-PCR were analyzed. By evaluating the efficiency (E) values, all 3 kits showed high sensitivity and similar results; while the highest level was detected with the Allplex™ 2019-nCoV Assay kit in the nucleocapsid (N) gene (E: 124%), the lowest was detected with the Double Gene™ RT-qPCR kit in the N and ORF 1ab genes (E: 90%). Of the samples included in the study, only 1 positive sample with low viral load was found to be negative when studied by pooling. The total number of kits to be used in pooled tests and then to individually retest the 5 samples in positive pools was calculated as 827 and the savings rate as 69.91% (1968/2815). Conclusion: The pooling strategy is an effective approach to extend the impact of limited testing resources and reagents available in certain periods of the COVID-19 pandemic. Testing by pooling samples requires improvement of RNA extraction methods and careful monitoring of RT-PCR test sensitivity to avoid missing low-positive entities. Therefore, based on the prevalence of COVID-19 in their regions, laboratories should conduct their own validation of pooling studies for RNA extraction and amplification methods they use.

Rapid and Effective Vitamin D Supplementation May Present Better Clinical Outcomes in COVID-19 (SARS-CoV-2) Patients by Altering Serum INOS1, IL1B, IFNg, Cathelicidin-LL37, and ICAM1.

BACKGROUND: We aimed to establish an acute treatment protocol to increase serum vitamin D, evaluate the effectiveness of vitamin D3 supplementation, and reveal the potential mechanisms in COVID-19. METHODS: We retrospectively analyzed the data of 867 COVID-19 cases. Then, a prospective study was conducted, including 23 healthy individuals and 210 cases. A total of 163 cases had vitamin D supplementation, and 95 were followed for 14 days. Clinical outcomes, routine blood biomarkers, serum levels of vitamin D metabolism, and action mechanism-related parameters were evaluated. RESULTS: Our treatment protocol increased the serum 25OHD levels significantly to above 30 ng/mL within two weeks. COVID-19 cases (no comorbidities, no vitamin D treatment, 25OHD <30 ng/mL) had 1.9-fold increased risk of having hospitalization longer than 8 days compared with the cases with comorbidities and vitamin D treatment. Having vitamin D treatment decreased the mortality rate by 2.14 times. The correlation analysis of specific serum biomarkers with 25OHD indicated that the vitamin D action in COVID-19 might involve regulation of INOS1, IL1B, IFNg, cathelicidin-LL37, and ICAM1. CONCLUSIONS: Vitamin D treatment shortened hospital stay and decreased mortality in COVID-19 cases, even in the existence of comorbidities. Vitamin D supplementation is effective on various target parameters; therefore, it is essential for COVID-19 treatment.