Comparison of humoral immune response in heterologous and homologous COVID-19 booster vaccine groups using CoronaVac and mRNA-based BNT162b2 vaccines.

BACKGROUND: Heterologous COVID-19 booster vaccination is an alternative strategy to homologous vaccination, especially in developing countries, due to shortages, delays, or unequal distribution of COVID-19 vaccines. We compared cohorts vaccinated with different vaccine combinations to investigate whether a heterologous booster dose of mRNA-based BNT162b2 vaccine boosts the immune response in individuals primed with the CoronaVac vaccine. METHODS: Anti-RBD IgG is generally measured 4 weeks after primary immunization and 4 weeks after booster vaccination. Data on anti-receptor-binding domain (anti-RBD) IgG antibody titers and clinical characteristics were provided by infection control units. RESULTS: The highest median anti-RBD IgG antibody titers (14589 AU/mL) after primary immunization was observed in the group vaccinated with two doses of BNT162b2 vaccine. Antibody titers were lower 4 months or more after the second CoronaVac vaccine dose in CoronaVac recipients with or without previous COVID-19. In the homologous COVID-19 booster vaccine group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of CoronaVac) the median anti-RBD titers decreased from 1025 to 242 AU/mL before the booster dose. In the heterologous group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of BNT162b2), the median anti-RBD titer increased to 31624 AU/mL, a 132-fold increase, 16 days after the booster dose. CONCLUSIONS: After the second dose of CoronaVac, protective neutralizing antibody levels decrease over time, and a booster dose is required. Heterologous COVID-19 booster vaccination with BNT162b2 is effective at boosting neutralizing antibody levels.

Comparison of humoral immune response in heterologous and homologous COVID-19 booster vaccine groups using CoronaVac and mRNA-based BNT162b2 vaccines

ABSTRACT Background: Heterologous COVID-19 booster vaccination is an alternative strategy to homologous vaccination, especially in developing countries, due to shortages, delays, or unequal distribution of COVID-19 vaccines. We compared cohorts vaccinated with different vaccine combinations to investigate whether a heterologous booster dose of mRNA-based BNT162b2 vaccine boosts the immune response in individuals primed with the CoronaVac vaccine. Methods: Anti-RBD IgG is generally measured 4 weeks after primary immunization and 4 weeks after booster vaccination. Data on anti-receptor-binding domain (anti-RBD) IgG antibody titers and clinical characteristics were provided by infection control units. Results: The highest median anti-RBD IgG antibody titers (14589 AU/mL) after primary immunization was observed in the group vaccinated with two doses of BNT162b2 vaccine. Antibody titers were lower 4 months or more after the second CoronaVac vaccine dose in CoronaVac recipients with or without previous COVID-19. In the homologous COVID-19 booster vaccine group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of CoronaVac) the median anti-RBD titers decreased from 1025 to 242 AU/mL before the booster dose. In the heterologous group (primed with two doses of CoronaVac 4 weeks apart and a single booster dose of BNT162b2), the median anti-RBD titer increased to 31624 AU/mL, a 132-fold increase, 16 days after the booster dose. Conclusions: After the second dose of CoronaVac, protective neutralizing antibody levels decrease over time, and a booster dose is required. Heterologous COVID-19 booster vaccination with BNT162b2 is effective at boosting neutralizing antibody levels.

Peripheral innate and adaptive immune cells during COVID-19: Functional neutrophils, pro-inflammatory monocytes, and half-dead lymphocytes.

BACKGROUND: A better understanding of innate and adaptive cells in COVID-19 is necessary for the development of effective treatment methods and vaccines. METHODS: We studied phenotypic features of innate and adaptive immune cells, oxidative burst, phagocytosis, and apoptosis. One hundred and three patients with COVID-19 were grouped according to their clinical features into the categories of mild (35%), moderate (40.8%), and severe (24.3%). RESULTS: Monocytes were CD16+ pro-inflammatory monocytes and tended to shed their HLA-DR, especially in severe cases (p < 0.01). Neutrophils were mature and functional, although a decline of their CD10 and CD16 was observed (p < 0.01). No defect was found in the reactive oxygen species production and their apoptosis. The percentage of natural killer cells was in the normal range, whereas the percentages of CD8+ NK and CD56+ T lymphocytes were found to be high (p < 0.01). Although the absolute numbers of all lymphocyte subsets were low and showed a tendency for a gradual decrease in accordance with the disease progression, the most decreased absolute number was that of B lymphocytes, followed by CD4+ T cells in the severe cases. The percentages of double-negative T cells; HLA-DR+ CD3+ and CD28- CD8+ subsets were found to be significantly increased. Importantly, we demonstrated the increased baseline activation of caspase-3 and increased lymphocyte apoptosis. CONCLUSION: We suggest that SARS-CoV-2 primarily affects the lymphocytes and not the innate cells. The increased baseline activation of Caspase-3 could make the COVID-19 lymphocytes more vulnerable to cell death. Therefore, this may interrupt the crosstalk between the adaptive and innate immune systems.

Immunological parameters associated with the severity of COVID-19 pneumonia in kidney transplant recipients.

PURPOSE: An outbreak of a novel respiratory disease due to coronavirus species was emerged in 2019 and named as Coronavirus Disease-2019 (COVID-19). Clinical and immunological factors affecting the course of COVID-19 in kidney transplant recipients (KTR) are not well-known. METHODS: In this prospective observational study, we presented 20 KTR with COVID-19 pnemonia and examined the factors predicting the severity of COVID-19. A total of 10 KTR without COVID-19 was used as control group. Lymphocyte subsets were determined by flow cytometry. In 13/20 patients, immunophenotyping was repeated 1 week later. RESULTS: Mean age of the patients was 50 ± 9 years. Patients were classified as mild-moderate (oxygen saturation: SO2 > 90%) and severe disease groups (SO2 ≤ 90%). Serum albumin and hemoglobin were lower and CRP, fibrinogen and peak D-dimer were higher in severe group. Peak CRP was inversely associated with nadir SO2 (r = - 0.68, p = 0.001). Neutrophil/lymphocyte ratio was higher in severe group (p = 0.01). CD3 + and CD4 + cells were lower and NK cell percentage (CD16 + 56 +) was higher in severe group. Percentage of spontaneously activated CD8 cells (CD8 + CD69 +) was higher in severe group. In comparison of KTR with and without COVID-19, CD8 + cells were lower but NK cell percentage was higher in KTR with COVID-19. CONCLUSION: In this pilot study, increased NK cells, activated CD8 + cells and decreased CD3 + and CD4 + cells were associated with severity of COVID-19 in KTR. Peripheral immunophenotyping of lymphocyte subtypes may provide prognostic information about the clinical course of COVID-19 in KTR.

Comparison of immunogenicity and reactogenicity of inactivated SARS-CoV-2 vaccine (CoronaVac) in previously SARS-CoV-2 infected and uninfected health care workers.

The effects of inactivated SARS-CoV-2 vaccine (CoronaVac) on previously naturally infected individuals are unknown. This study compared immunogenicity and reactogenicity of CoronaVac in once naturally infected health-care workers (HCWs) and uninfected HCWs. All HCWs were immunized with two doses of CoronaVac (600 U/0.5 ml) intramuscularly at a 28-day interval. Adverse reactions were obtained by web-based questionnaires or telephone calls seven days after each vaccine dose. Detection of antibody levels against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein was done four weeks after the second dose of the vaccine. We enrolled 103 previously naturally infected and 627 uninfected HCWs. The mean time for vaccination after the first nasopharyngeal SARS-CoV-2 positivity was 64 days (range: 15-136 days) in previously naturally infected HCWs. Among the previously naturally infected HCWs, 41 (40%) were asymptomatic, 52 (50%) had mild upper respiratory tract infections, 10 (105) had pneumonia, and only 6 (5%) were hospitalized. Any reported adverse reactions, either from the first dose or the second dose of vaccine administration, did not differ between previously infected and uninfected HCWs. Anti-RBD antibody titers were obtained in 50 (51%) of 103 previously infected HCWs and 142 (23%) of 627 uninfected HCWs. Anti-RBD antibody titers were significantly higher in HCWs with a previous natural infection (median 1220 AU/ml, range: 202-10328 AU/mL) than in uninfected HCWs (median: 913 AU/ml, range: 2.8-15547 AU/mL, p = .032). CoronaVac administration was safe and may elicit higher antibody responses in previously naturally infected individuals.

Virulence Genes and Antibiotic Susceptibilities of Uropathogenic E. coli Strains.

BACKGROUND: The aim of this study is to detect the presence of and possible relation between virulence genes and antibiotic resistance in E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (UTI). METHODS: 62 E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (50 strains isolated from acute uncomplicated cystitis cases (AUC); 12 strains from acute uncomplicated pyelonephritis cases (AUP)) were screened for virulence genes [pap (pyelonephritis-associated pili), sfa/foc (S and F1C fimbriae), afa (afimbrial adhesins), hly (hemolysin), cnf1 (cytotoxic necrotizing factor), aer (aerobactin), PAI (pathogenicity island marker), iroN (catecholate siderophore receptor), ompT (outer membrane protein T), usp (uropathogenic specific protein)] by PCR and for antimicrobial resistance by disk diffusion method according to CLSI criteria. RESULTS: It was found that 56 strains (90.3%) carried at least one virulence gene. The most common virulence genes were ompT (79%), aer (51.6%), PAI (51.6%) and usp (56.5%). 60% of the strains were resistant to at least one antibiotic. The highest resistance rates were against ampicillin (79%) and co-trimoxazole (41.9%). Fifty percent of the E. coli strains (31 strains) were found to be multiple resistant. Eight (12.9%) out of 62 strains were found to be ESBL positive. Statistically significant relationships were found between the absence of usp and AMP - SXT resistance, iroN and OFX - CIP resistance, PAI and SXT resistance, cnf1 and AMP resistance, and a significant relationship was also found between the presence of the afa and OFX resistance. CONCLUSIONS: No difference between E. coli strains isolated from two different clinical presentations was found in terms of virulence genes and antibiotic susceptibility.

Predictors of fatality in pandemic influenza A (H1N1) virus infection among adults.

BACKGROUND: The fatality attributed to pandemic influenza A H1N1 was not clear in the literature. We described the predictors for fatality related to pandemic influenza A H1N1 infection among hospitalized adult patients. METHODS: This is a multicenter study performed during the pandemic influenza A H1N1 [A(H1N1)pdm09] outbreak which occurred in 2009 and 2010. Analysis was performed among laboratory confirmed patients. Multivariate analysis was performed for the predictors of fatality. RESULTS: In the second wave of the pandemic, 848 adult patients were hospitalized because of suspected influenza, 45 out of 848 (5.3%) died, with 75% of fatalities occurring within the first 2 weeks of hospitalization. Among the 241 laboratory confirmed A(H1N1)pdm09 patients, the case fatality rate was 9%. In a multivariate logistic regression model that was performed for the fatalities within 14 days after admission, early use of neuraminidase inhibitors was found to be protective (Odds ratio: 0.17, confidence interval: 0.03-0.77, p=0.022), nosocomial infections (OR: 5.7, CI: 1.84-18, p=0.013), presence of malignant disease (OR: 3.8, CI: 0.66-22.01, p=0.133) significantly increased the likelihood of fatality. CONCLUSIONS: Early detection of the infection, allowing opportunity for the early use of neuraminidase inhibitors, was found to be important for prevention of fatality. Nosocomial bacterial infections and underlying malignant diseases increased the rate of fatality.

Liver transplant in a patient with active pulmonary tuberculosis.

OBJECTIVES: Immunosuppressive treatment generally increases the severity of active infection. Therefore, liver transplant is contraindicated in the presence of active tuberculosis. Despite the importance of supportive treatment, liver transplant is the only treatment for fulminant hepatic failure. MATERIALS AND METHODS: We report a case of successful liver transplant for fulminant hepatic failure in the presence of active tuberculosis infection. RESULTS: We immediately performed a liver transplant from a live donor. The patient received low-dose immunosuppressive treatment and antituberculosis treatment. The patient was cured and discharged on the 25th day after surgery. We stopped antituberculosis treatment 10 months after discharge. The patient has been followed for 32 months after transplant with normal graft function and has been free of pulmonary tuberculosis infection. CONCLUSIONS: Liver transplant can be performed in cirrhotic patients with active infections, such as tuberculosis, as a life-saving procedure.

Mycotic ascending aortic pseudoaneurysm at aortic cannulation site.

Mycotic aneurysm of the aorta is a rare but highly fatal complication of coronary bypass surgery. A 49-year-old man developed mycotic pseudoaneurysm in the ascending aorta after coronary bypass in another hospital. Computed tomography showed the pseudoaneurysm originated from the previous aortic cannulation site. The defect was successfully repaired with pericardial-pledgeted sutures.

[Investigation of intestinal parasites in AIDS patients]. / AIDS hastalarinda barsak parazitlerinin arastirilmasi.

In this study, enteric parasites were investigated in the stool samples of 38 AIDS patients (23 with chronic diarrhea and 15 without diarrhea) prospectively. At least three stool samples from each patient were investigated microscopically for ova or trophozoites. The samples were concentrated with formol-ether method and wet preparations stained with lugol were examined. In addition, the concentrated samples were stained with modified asid-fast (Kinyoun's), rhodamine-auramine, modified trichrom and calcoflor methods. Enteric parasites were detected in 18 (47%) of the 38 patients, 16 patients harbored a single parasite, and 2 patients were found to be infected with more than one parasite. Only one (7%) of 15 AIDS patients without diarrhea, were found to be infected with Giardia lamblia. On the other hand, 17 (74%) of 23 AIDS patients with chronic diarrhea were found to be infected with various enteric parasites. Cryptosporidium spp. was detected in 9 (39%) of these 23 patients, and in 2 of them Microsporidium spp. accompanied Cryptosporidium. In 2 (9%) of these 23 patients G. lamblia were detected, while Isospora belli, Blastocystis hominis, Entamoeba histolytica, Strongyloides stercoralis and Trichuris trichiura were detected in one patient each. As a result, the detection rate of emerging parasites, including Cryptosporidium spp, Microsporidium spp, I. belli, B. hominis, and S. stercoralis was significantly higher than conventional parasites (39% versus 13%; z=2.34, p=0.01), and CD4 T cell counts were found to be significantly lower among AIDS patients with chronic diarrhea than those without diarrhea (x2=34.33, p<0.001).