The Practice of Antimicrobial Stewardship in Thoracic Surgery and its Effectiveness.

This study examines the effects of the bundle of antimicrobial stewardship measures for prophylactic antibiotics among thoracic surgery patients. A local protocol, based on current guidelines starting from December 2014, was developed by the Infection Control and Thoracic Surgery Teams. The effects of this protocol were assessed by monitoring a total of 1380 patients before and after its implementation from January 1, 2011, to December 31, 2022.

Discrepancy between IDSA and ESGBOR in Lyme disease: Individual participant meta-analysis in Türkiye.

BACKGROUND: The evidence on the prevalence of Lyme borreliosis (LB) is limited, but there is a suspicion of overdiagnosis of LB in recent years. We reviewed the LB diagnosis and treatment-related data in Türkiye, based on the Infectious Diseases Society of America (IDSA) 2020 and European Society of Clinical Microbiology and Infectious Diseases Study Group for Lyme Borreliosis (ESGBOR) 2018 guidelines. By detecting the disagreements between these two, we outlined the areas to be improved for future guidelines. METHODS: We performed a literature search according to the PRISMA guidelines in PubMed, Ovid-Medline, Web of Science, Turkish Medline, Scopus, CINAHL, ULAKBIM TR Index, Google Scholar and Cochrane Library databases. We included the published cases in a database and evaluated according to IDSA and ESGBOR guidelines. We outlined the reasons for misdiagnoses and inappropriate uses of antibiotics. RESULTS: We included 42 relevant studies with 84 LB cases reported from Türkiye between 1990 and December 2022. Among 84 cases, the most common clinical findings were nervous system findings (n = 37, 44.0%), erythema migrans (n = 29, 34.5%) and ophthalmologic findings (n = 15, 17.9%). The IDSA 2020 and ESGBOR 2018 guidelines agreed on the diagnosis of 71 (84.5%) cases; there was an agreement that 31 cases (36.9%) were misdiagnosed and 40 cases (47.6%) were correctly diagnosed, and there was disagreement for 13 cases (15.5%). Serum immunoglobulin M (IgM), IgG measurements by ELISA and western blot were widely performed, and they were effective in definitive diagnosis merely when used according to guidelines. Inappropriate use of antibiotics was detected in 42 (50.0%) of cases which were classified in the following categories: incorrect LB diagnosis, inappropriate choice of antibiotic, inappropriate route of drug administration and prolonged antibiotic treatment. CONCLUSION: Overdiagnosis and non-adherence to guidelines is a common problem. The discordance between seroprevalence and clinical studies necessitates a consensus over the best clinical approach.

Erythrocyte-Leveraged Oncolytic Virotherapy (ELeOVt): Oncolytic Virus Assembly on Erythrocyte Surface to Combat Pulmonary Metastasis and Alleviate Side Effects.

Despite being a new promising tool for cancer therapy, intravenous delivery of oncolytic viruses (OVs) is greatly limited by poor tumor targeting, rapid clearance in the blood, severe organ toxicity, and cytokine release syndrome. Herein, a simple and efficient strategy of erythrocyte-leveraged oncolytic virotherapy (ELeOVt) is reported, which for the first time assembled OVs on the surface of erythrocytes with up to near 100% efficiency and allowed targeted delivery of OVs to the lung after intravenous injection to achieve excellent treatment of pulmonary metastases while greatly improving the biocompatibility of OVs as a drug. Polyethyleneimine (PEI) as a bridge to assemble OVs on erythrocytes also played an important role in promoting the transfection of OVs. It is found that ELeOVt approach significantly prolonged the circulation time of OVs and increased the OVs distribution in the lung by more than tenfold, thereby significantly improving the treatment of lung metastases while reducing organ and systemic toxicity. Taken together, these findings suggest that the ELeOVt provides a biocompatible, efficient, and widely available approach to empower OVs to combat lung metastasis.

Does Emerging Carbapenem Resistance in Acinetobacter baumannii Increase the Case Fatality Rate? Systematic Review and Meta-Analysis.

BACKGROUND: In the era of rising carbapenem resistance, we aimed to investigate the change in mortality rate and positivity of carbapenemase genes in Acinetobacter baumannii. METHODS: Preferred Reporting Items for Systematic Review (PRISMA) guidelines were adopted in this systematic review. Our literature search included the Cochrane Library, Pubmed, Scopus, Web of Science, Medline, Tubitak TR Dizin, and Harman databases for studies dating back from 2003 to 2023 reporting bloodstream A. baumannii infections in Türkiye. A simple linear regression model was used to determine the association between resistance, mortality, and time. RESULTS: A total of 1717 studies were identified through a literature search, and 21 articles were selected based on the availability of the data regarding mortality and resistance rate (four articles) or the molecular epidemiology of carbapenem-resistant A. baumannii (17 articles) in Türkiye. From 2007 to 2018, the carbapenem resistance rate increased (p = 0.025). The OXA-23 and OXA-58 positivities were inversely correlated (p = 0.025). CONCLUSIONS: Despite the emergence of carbapenem resistance, mortality did not increase in parallel, which may be due to improved medical advancements or the fitness cost of bacteria upon prolonged antimicrobial exposure. Therefore, we suggest further global research with the foresight to assess clonal relatedness that might affect the carbapenem resistance rate.

LPS adsorption and inflammation alleviation by polymyxin B-modified liposomes for atherosclerosis treatment.

Chronic inflammation is critical in the onset and progression of atherosclerosis (AS). The lipopolysaccharide (LPS) level in the circulation system is elevated in AS patients and animal models, which is correlated with the severity of AS. Inspired by the underlying mechanism that LPS could drive the polarization of macrophages toward the M1 phenotype, aggravate inflammation, and ultimately contribute to the exacerbation of AS, LPS in the circulation system was supposed to be the therapeutic target for AS treatment. In the present study, polymyxin (PMB) covalently conjugated to PEGylated liposomes (PLPs) were formulated to adsorb LPS through specific interactions between PMB and LPS. In vitro, the experiments demonstrated that PLPs could adsorb LPS, reduce the polarization of macrophages to M1 phenotype and inhibit the formation of foam cells. In vivo, the study revealed that PLPs treatment reduced the serum levels of LPS and pro-inflammatory cytokines, decreased the proportion of M1-type macrophages in AS plaque, stabilized AS plaque, and downsized the plaque burdens in arteries, which eventually attenuated the progression of AS. Our study highlighted LPS in the circulation system as the therapeutic target for AS and provided an alternative strategy for AS treatment.

COVID-19 associated bacterial infections in intensive care unit: a case control study.

We described the secondary bacterial infections (SBI) among COVID-19 patients in comparison with non-COVID-19 patients. We performed a retrospective case-control study between January 01, 2020 and April 01, 2022. Including the adult patients, who stayed ≥ 72 h in intensive care unit (ICU). In total 405 patients were included, 135 had (33.3%) COVID-19, with similar age and gender. The length of stay in ICU was not different (11.4 vs 8.2, p = 0.109), however mean intubation days were higher among COVID-19 cases (6.5 vs 3.8, p = 0.005), SBI were more common among COVID-19 cases (34% vs 10.7%, p < 0.001). Among the patients with pneumonia, the rate of gram-positive bacteria was higher in COVID-19 group than the control group (39% vs 5%, p = 0.006). The predictors for SBI were having COVID-19 (OR: 2.3, Cl 1.25-4.32, p = 0.008), days of intubation (OR: 1.05, Cl 1.01-1.10, p = 0.004), and being male (OR: 2, Cl 1.12-3.58, p = 0.018). The predictors of mortality were COVID-19 (OR: 2.38, Cl 1.28-4.42, p = 0.006), days of intubation (OR: 1.06, Cl 1.03-1.09, p < 0.001), active hematologic malignancy (OR: 3.1, Cl: 1.33-7.28, p = 0.09), active solid tumors (OR: 2.44, Cl 1.21-4.91, p = 0.012), and coronary artery diseases (OR: 1.8, Cl 1.01-3.52, p = 0.045). The most common SBI in COVID-19 patients were methicillin-sensitive Staphylococcus aureus. No carbapenem-resistant Enterobacterales related infections were detected in COVID-19 patients.

Higher rates of cefiderocol resistance among NDM producing Klebsiella bloodstream isolates applying EUCAST over CLSI breakpoints.

BACKGROUND: Cefiderocol is generally active against carbapenem-resistant Klebsiella spp. (CRK) with higher MICs against metallo-beta-lactamase producers. There is a variation in cefiderocol interpretive criteria determined by EUCAST and CLSI. Our objective was to test CRK isolates against cefiderocol and compare cefiderocol susceptibilities using EUCAST and CLSI interpretive criteria. METHODS: A unique collection (n = 254) of mainly OXA-48-like- or NDM-producing CRK bloodstream isolates were tested against cefiderocol with disc diffusion (Mast Diagnostics, UK). Beta-lactam resistance genes and multilocus sequence types were identified using bioinformatics analyses on complete bacterial genomes. RESULTS: Median cefiderocol inhibition zone diameter was 24 mm (interquartile range [IQR] 24-26 mm) for all isolates and 18 mm (IQR 15-21 mm) for NDM producers. We observed significant variability between cefiderocol susceptibilities using EUCAST and CLSI breakpoints, such that 26% and 2% of all isolates, and 81% and 12% of the NDM producers were resistant to cefiderocol using EUCAST and CLSI interpretive criteria, respectively. CONCLUSIONS: Cefiderocol resistance rates among NDM producers are high using EUCAST criteria. Breakpoint variability may have significant implications on patient outcomes. Until more clinical outcome data are available, we suggest using EUCAST interpretive criteria for cefiderocol susceptibility testing.

The challenges in the monitoring of infectious diseases after the earthquake in Türkiye in 2023.

After the devastating earthquake in Türkiye and Syria in February, 2023, the long-term failure to meet the need for shelter, unfavourable living conditions in tent settlements, poor access to clean drinking water, water suitable for personal hygiene, and sanitary facilities, as well as interruptions in provision of primary health-care services, have emerged as the most important risk factors contributing to the spread of infectious diseases. 3 months after the earthquake, most of these problems persist in Türkiye. Data on the control of infectious diseases are scarce according to the reports prepared by medical specialist associations based on observations of health-care providers working in the region and statements made by the local health authorities. According to these unsystematised data, and considering the conditions in the region, faecal-oral transmissible gastrointestinal infections, as well as respiratory and vector-borne infections, are the main challenges. Vaccine-preventable diseases, such as measles, varicella, meningitis, and polio can be spread in temporary shelters due to interrupted vaccine services and crowded living conditions. In addition to controlling risk factors for infectious diseases, sharing data on the status and control of infectious diseases in the region with the community, health-care providers, and relevant expert groups should be a priority to improve the understanding of the effects of interventions and prepare for possible infectious disease outbreaks.

Virus-Protein Corona Replacement Strategy to Improve the Antitumor Efficacy of Intravenously Injected Oncolytic Adenovirus.

Intravenous administration of oncolytic adenoviruses (OVs) is a hopeful tumor therapeutic modality. However, the sharp clearance of OVs by the immune system dampens its effectiveness. Many studies have attempted to extend the circulation of intravenously administered OVs, almost all by preventing OVs from binding to neutralizing antibodies and complements in the blood, but the results have not been satisfactory. In contrast to previous conclusions, we found that the key to improving the circulation of OVs is to prevent the formation of the virus-protein corona rather than simply preventing the binding of neutralizing antibodies or complements to OVs. After identifying the key protein components of the virus-protein corona, we proposed a virus-protein corona replacement strategy, where an artificial virus-protein corona was formed on OVs to completely prevent the interaction of OVs with key virus-protein corona components in the plasma. It was found that this strategy dramatically prolonged the circulation time of OVs by over 30 fold and increased the distribution of OVs in tumors by over 10-fold, resulting in superior antitumor efficacy in primary and metastatic tumor models. Our finding provides a perspective on intravenous delivery of OVs, shifting the focus of future studies from preventing OV binding with neutralization antibodies and complements to preventing OVs from interacting with key virus-protein corona components in the plasma.

Uptake of COVID-19 vaccines among healthcare workers and the effect of nudging interventions: A mixed methods study.

BACKGROUND: During the coronavirus disease (COVID-19) pandemic, vaccination of healthcare workers (HCWs) has a critical role because of their high-risk exposure and being a role model. Therefore, we aimed to investigate vaccine hesitancy and the role of mandatory polymerase chain reaction (PCR) testing and education for vaccine uptake. METHODS: We conducted an explanatory sequential designed observational mixed-methods study, including quantitative and qualitative sections consecutively in two different pandemic hospitals between 15 September 2021 and 1 April 2022. The characteristics of vaccinated and unvaccinated HCWs were compared. The vaccine hesitancy scales were applied, and the effect of nudging, such as mandatory PCR and education, were evaluated. In-depth interviews were performed to investigate the COVID-19 vaccine hesitancy among HCWs according to Health Belief Model. RESULTS: In total, 3940 HCWs were included. Vaccine hesitancy was more common among males than females, the ancillary workers than other health professions, and nonmedical departments than other departments. After the mandatory weekly PCR request nudge, 83.33 % (130/156) vaccine-hesitant HCWs were vaccinated, and 8.3 % (13/156) after the small group seminars and mandatory PCR every two days. The rate of COVID-19 vaccination was raised from 95.5 % to 99.67  % (3927/3940). At the end of in-depth interviews (n = 13), the vaccine hesitancy determinants were distrust, fear of uncertainty, immune confidence and spirituality, the media effect, social pressure, and obstinacy. CONCLUSIONS: The nudging interventions such as mandatory PCR testing and small group seminars helped raise the rate of COVID-19 vaccination; the most effective one is mandatory PCR.

Effectiveness of tocilizumab in non-intubated cases with COVID-19: a systematic review and meta-analysis.

PURPOSE: Tocilizumab, a monoclonal IL-6 receptor blocker, is an effective agent for severe-to-critical cases of COVID-19; however, its target patients for the optimum use need to be detailed. We performed a systematic review and meta-analysis to define its effect among severely ill but non-intubated cases with COVID-19. METHODS: We searched PubMed, Scopus, Web of Science, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Medrxiv, and Biorxiv until February 13, 2022, for non-intubated cases, and included randomized-controlled trials (RCT) based on bias assessment. The primary outcomes were the requirement of invasive mechanical ventilation and mortality. Random effect and fixed-effect models were used. The heterogeneity was measured using the χ2 and I2 statistics, with χ2 p ≤ 0.05 and I2 ≥ 50% indicating the presence of significant heterogeneity. We registered the study to the International Prospective Register of Systematic Reviews (PROSPERO) with the registration number CRD42021232575. RESULTS: Among 261 articles, 11 RCTs were included. The pooled analysis of the 11 RCTs demonstrated that the rate of mortality was significantly lower in the tocilizumab group than in the control group (20.0% and 24.2%, OR: 0.84, 95% CI 0.73-0.96, and heterogeneity I2 = 0%. p = 0.82.). The mechanical ventilation rate was lower in the tocilizumab group than the control group (27% vs 35.2%, OR: 0.76, 95% CI 0.67-0.86, and heterogeneity I2 = 6%. p = 0.39). CONCLUSION: Among non-intubated severe COVID-19 cases, tocilizumab reduces the risk of invasive mechanical ventilation and mortality compared to standard-of-care treatment.

Vaccines and therapeutics for immunocompromised patients with COVID-19.

The COVID-19 pandemic has disproportionately impacted immunocompromised patients. This diverse group is at increased risk for impaired vaccine responses, progression to severe disease, prolonged hospitalizations and deaths. At particular risk are people with deficiencies in lymphocyte number or function such as transplant recipients and those with hematologic malignancies. Such patients' immune responses to vaccination and infection are frequently impaired leaving them more vulnerable to prolonged high viral loads and severe complications of COVID-19. Those in turn, have implications for disease progression and persistence, development of immune escape variants and transmission of infection. Data to guide vaccination and treatment approaches in immunocompromised people are generally lacking and extrapolated from other populations. The large clinical trials leading to authorisation and approval of SARS-CoV-2 vaccines and therapeutics included very few immunocompromised participants. While experience is accumulating, studies focused on the special circumstances of immunocompromised patients are needed to inform prevention and treatment approaches.

COVID-19-associated mucormycosis: a systematic review and meta-analysis of 958 cases.

BACKGROUND: Mucormycosis, a rare fungal infection, has shown an increase in the number of reported cases during the COVID-19 pandemic. OBJECTIVES: To provide a comprehensive insight into the characteristics of COVID-19-associated mucormycosis, through a systematic review and meta-analysis. METHODS OF DATA SYNTHESIS: Demographic information and clinical features were documented for each patient. Logistic regression analysis was used to predict the risk of mortality. DATA SOURCES: PubMed, Scopus, Web of Science, Cochrane, CINAHL, Ovid MEDLINE, and FungiSCOPE. STUDY ELIGIBILITY CRITERIA: Studies reporting individual-level information in patients with adult COVID-19-associated mucormycosis (CAM) between 1 January 2020 and 28 December 2022. PARTICIPANTS: Adults who developed mucormycosis during or after COVID-19. INTERVENTIONS: Patients with and without individual clinical variables were compared. ASSESSMENT OF RISK OF BIAS: Quality assessment was performed based on the National Institutes of Health quality assessment tool for case series studies. RESULTS: Nine hundred fifty-eight individual cases reported from 45 countries were eligible. 88.1% (844/958) were reported from low- or middle-income countries. Corticosteroid use for COVID-19 (78.5%, 619/789) and diabetes (77.9%, 738/948) were common. Diabetic ketoacidosis (p < 0.001), history of malignancy (p < 0.001), underlying pulmonary (p 0.017), or renal disease (p < 0.001), obesity (p < 0.001), hypertension (p 0.040), age (>65 years) (p 0.001), Aspergillus coinfection (p 0.037), and tocilizumab use during COVID-19 (p 0.018) increased the mortality. CAM occurred on an average of 22 days after COVID-19 and 8 days after hospitalization. Diagnosis of mucormycosis in patients with Aspergillus coinfection and pulmonary mucormycosis was made on average 15.4 days (range, 0-35 days) and 14.0 days (range, 0-53 days) after hospitalization, respectively. Cutaneous mucormycosis accounted for <1% of the cases. The overall mortality rate was 38.9% (303/780). CONCLUSION: Mortality of CAM was high, and most reports were from low- or middle-income countries. We detected novel risk factors for CAM, such as older age, specific comorbidities, Aspergillus coinfection, and tocilizumab use, in addition to the previously identified factors.

Alterations in vaginal microbiota among pregnant women with COVID-19.

The maintenance of vaginal microbiota is an important factor to achieve optimum pregnancy outcomes. The study aims to describe the alterations in the composition of vaginal microbiota in pregnant women with coronavirus disease 2019 (COVID-19). This was a prospective case-control study. Vaginal swabs were collected from uninfected pregnant women (n = 28) and pregnant women with COVID-19 (n = 19) during the active phase of infection and within a month after recovering from infection. The vaginal microbiota on the swabs was examined by 16S rRNA gene sequencing. Shannon index indicates that alpha diversity is significantly higher in women with COVID-19 (p = 0.012). There was a significant decrease in Firmicutes (p = 0.014) with an increase in Bacteroidota (p = 0.018) phyla and a decrease in Lactobacillus (p = 0.007) genus in women with COVID-19 than those of uninfected pregnant women. The relative abundance of L. crispatus, L. iners, L. gasseri, and L. jensenii were lower in the COVID-19 group than in uninfected pregnant women. In subgroup analysis, the amount of Ureaplasma spp. was higher in women with moderate/severe than those of asymptomatic/mild disease (p = 0.036). The study revealed that vaginal dysbiosis with low abundance of Lactobacillus species occurred in pregnant women infected with severe acute respiratory syndrome coronavirus-2. These findings may lead to new studies to elucidate the risk of pregnancy adverse outcomes related to COVID-19.

Plasma proteomics identify potential severity biomarkers from COVID-19 associated network.

PURPOSE: Coronavirus disease 2019 (COVID-19) continues to threaten public health globally. Severe acute respiratory coronavirus type 2 (SARS-CoV-2) infection-dependent alterations in the host cell signaling network may unveil potential target proteins and pathways for therapeutic strategies. In this study, we aim to define early severity biomarkers and monitor altered pathways in the course of SARS-CoV-2 infection. EXPERIMENTAL DESIGN: We systematically analyzed plasma proteomes of COVID-19 patients from Turkey by using mass spectrometry. Different severity grades (moderate, severe, and critical) and periods of disease (early, inflammatory, and recovery) are monitored. Significant alterations in protein expressions are used to reconstruct the COVID-19 associated network that was further extended to connect viral and host proteins. RESULTS: Across all COVID-19 patients, 111 differentially expressed proteins were found, of which 28 proteins were unique to our study mainly enriching in immunoglobulin production. By monitoring different severity grades and periods of disease, CLEC3B, MST1, and ITIH2 were identified as potential early predictors of COVID-19 severity. Most importantly, we extended the COVID-19 associated network with viral proteins and showed the connectedness of viral proteins with human proteins. The most connected viral protein ORF8, which has a role in immune evasion, targets many host proteins tightly connected to the deregulated human plasma proteins. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma proteomes from critical patients are intrinsically clustered in a distinct group than severe and moderate patients. Importantly, we did not recover any grouping based on the infection period, suggesting their distinct proteome even in the recovery phase. The new potential early severity markers can be further studied for their value in the clinics to monitor COVID-19 prognosis. Beyond the list of plasma proteins, our disease-associated network unravels altered pathways, and the possible therapeutic targets in SARS-CoV-2 infection by connecting human and viral proteins. Follow-up studies on the disease associated network that we propose here will be useful to determine molecular details of viral perturbation and to address how the infection affects human physiology.

The Effect of Vaccination with Pfizer-BioNTech or CoronaVac on Disease Prognosis Among Hospitalized COVID-19 Patients.

Objective: The Turkish Ministry of Health offered two types of vaccines by January 13, 2021, which are CoronaVac (Sinovac Biotech, China) and Pfizer-BioNTech. We aimed to describe the impact of the CoronaVac and Pfizer-BioNTech vaccines on clinical outcomes among hospitalized patients during a six-month period. Methods: We included patients older than 18 years old and hospitalized because of COVID-19 when the vaccines were available. We conducted the study at Koç University Hospital and American Hospital between June 2021, six months after the vaccination started, and December 2021. Results: In total, 444 RT-PCR confirmed hospitalized patients were included. The mean age of the patients was 59 (standard deviation [SD]=18), and 42.8% were female. The most common comorbidity was hypertension (39%), followed by diabetes mellitus (27%), cardiovascular diseases (18.4%), chronic lung diseases (14.6%), cancer (9.2%), and chronic renal diseases (8%). In multivariate analysis, no vaccination (OR=4.7, CI=2.25-10.06; p<0.001), age >65 (OR=5.2, CI=2.25-11.98; p<0.001), cancer (OR=7.6, CI=3.04-19.31; p<0.001), and chronic kidney disease (OR=3.1, CI=1.14-8.74; p=0.026) significantly increased mortality in COVID-19 patients. Eighteen percent of patients were in the intensive care unit (ICU). One hundred eighty-one patients (40.8%) were non-vaccinated before their admission, and their mortality (17.6%) was higher compared to the patients who were vaccinated with at least one type of vaccine (p=0.002). None of the patients who received two doses of Pfizer-BioNTech vaccines died. Conclusion: Among the inpatients with COVID-19, the predictors for mortality were being unvaccinated, older age, cancer, chronic kidney disease, and cardiovascular diseases. Among the vaccinated inpatients, having two doses of the Pfizer-BioNTech vaccine was the only effective protective measure against mortality, and two doses of the CoronaVac vaccine had no significant effect in preventing fatality.

B Cell Subtypes in Individuals Received mRNA or Inactivated Vaccine Boosters After Fully Vaccinated with CoronaVac: A Longitudinal Study.

In this study, we aimed to investigate the changes in the B cell subpopulations after homologous or heterologous COVID-19 boosters. Blood samples were collected after baseline (3-5 months after two doses of CoronaVac), 1 and 3 months after BNT162b2 (n=28 and n=6), and CoronaVac (n=7 and n=4) boosters. Peripheral blood mononuclear cells (PBMCs) were isolated and stained with B cell markers, the ratios of naïve (CD19+CD20+CD27-), memory (CD19+CD20+CD27+), memory B cells expressing IgG (CD19+CD20+CD27+IgG+), and effector memory B cells (CD19+CD20+CD27+CD38+) were identified with flow cytometry. Significantly higher expression of memory B cells was observed in one month with BNT162b2 (12.16% one month, 5.98% three months) and CoronaVac (14.18% one month, 9.00% three months) boosters. IgG expressing memory B cell expression was significantly higher with BNT162b2 than with CoronaVac booster in one month (22.70% and 13.95%, respectively). The ratio of effector B cells in the first month after CoronaVac booster (25.44%) was significantly higher than the BNT162b2 booster (9.90%, p =0.0263).