Quantitation of antibodies to the spike protein of severe acute respiratory syndrome coronavirus 2  (SARS‐CoV‐2) was performed for the detection of adaptive immune response in healthcare workers (HCWs) vaccinated with CorovaVac. We prospectively recruited HCWs from a university hospital in Turkey. Serum samples from 1072 HCWs were obtained following 28 days of the first, and 21 days of the second dose. Detection and quantitation of SARS‐CoV‐2 antispike antibodies were performed by the chemiluminescent microparticle immunoassay (SARS‐CoV‐2 IgG II Quant; Abbott). Results greater than or equal to the cutoff value 50.0 AU/ml were reported as positive. After the first dose, antispike antibodies were detected in 834 of 1072 (77.8%) HCWs. Seropositivity was higher among females (84.6%) than males (70.6%) ( p < 0.001) and was found to be highest in both women and men between the ages of 18–34. After the second dose, antibodies were detected in 1008 of 1012 (99.6%) HCWs. Antibody titers were significantly higher in those who had coronavirus disease‐2019 before vaccination than those who did not ( p < 0.001). Antibody positivity and median antibody titers were significantly less in HCWs with chronic diseases compared to those without ( p < 0.05 and p < 0.001, respectively). In conclusion, our findings indicated that a relatively high frequency (99.6%) of humoral immunity was produced in HCWs aged 18–59 after two doses of CoronaVac. Quantitation of antibodies may help facilitate longitudinal monitoring of the antibody response, which will be especially useful in deciding the dose of the vaccine in vulnerable groups such as those over 60 years of age and those with chronic diseases.

Objectives During COVID-19 pandemic, the absence of immunity in the population left them susceptible to infection with SARS-CoV-2; healthcare workers (HCWs) being in the highest risk group. This study intends to assess and follow up the humoral immunity in HCWs vaccinated with an inactive virus vaccine (CoronaVac). Study Design This is a prospective observational study. Methods A total of 1072 HCWs were investigated for the presence of IgG antibodies to the receptor binding domain (RBD) of the S1 subunit of the spike protein of SARS-CoV-2 after vaccination. Blood samples were obtained following 28 days of the first dose, 21 days of the second dose, and three months after the second dose. Detection of anti-spike antibodies was performed by the chemiluminescent microparticle immunoassay (CMIA) method (SARS-CoV-2 IgG II Quant, Abbott, Ireland). Results greater than or equal to the cutoff value 50.0 AU/mL were reported as positive. Results Four weeks after the first dose of vaccine, anti-spike antibodies were detected in 834/1072 (77.8%) of HCWs. Seropositivity was higher among females (84.6%) than males (70.6%) (p<0.001) and was found to be highest in both women and men between the ages of 18-34. Anti-spike antibodies were detected in 1008 of 1012 (99.6%) after 21 days of the second dose, and in 803 of 836 (96.1%) after three months of the second dose. Conclusions CoronaVac was found to be highly immunogenic after two consecutive doses performed 28 days apart to HCWs, however the immunogenicity declined significantly (p<0.001) after three months following the second dose of vaccine.

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.

Objectives Aerosols formed during dental treatments have a huge risk for the spread of bacteria and viruses. This study is aimed at determining which part of the working area and at what size aerosol is formed and ensuring more effective use of HEPA-filtered devices. Materials and methods Anterior tooth preparation was performed by one dentist with one patient. Particle measurements were made using an airborne particle counter and were taken at four different locations: the chest of the patient, the chest of the dentist, the center of the room, and near the window. Three groups were determined for this study: group 1: measurement in a 24-h ventilated room (before the tooth preparation, empty room), group 2: measurement with the use of saliva ejector (SE), and group 3: measurement with the use of saliva ejector and HEPA-filtered extra-oral suction (HEOS) unit. ResultsThe particles generated during tooth preparation were separated according to their sizes; the concentration in different locations of the room and the efficiency of the HEOS unit were examined. Conclusions The present study showed that as the particle size increases, the rate of spread away from the dentist's working area decreases. The HEPA-filtered extra-oral suction unit is more effective on particles smaller than 0.5 microns. Therefore, infection control methods should be arranged according to these results. Clinical relevance The effective and accurate use of HEPA-filtered devices in clinics significantly reduces the spread of bacterial and viral infections and cross-infection.

Çalışmamızda, hastanemizde otomatize sistem ile meropeneme dirençli veya doza bağlı duyarlı saptanan Enterobacterales suşlarında fenotipik ve genotipik yöntemlerle karbapenemazların varlığının araştırılması amaçlandı. Karbapenemazlar, karbapenemler dahil olmak üzere çoğu β-laktamı hidrolize ederler. Bu enzimleri üreten suşların saptanmasında birçok fenotipik ve genotipik yöntemler kullanılmaktadır. Genotipik yöntemlerden polimeraz zincir reaksiyonu zaman alıcı ve pahalı olmasına rağmen altın standart yöntemdir. Gram negatif bakterilerde artan direnç nedeniyle karbapenem direnç genlerinin profilinin belirlenmesi antibiyotik kullanım politikalarının belirlenmesinde yol gösterici olması açısından önem taşımaktadır. Çalışmamızda, Aralık 2019- Aralık 2020 tarihleri arasında bir yıllık süreçte otomatize sistem ile meropeneme dirençli veya doza bağlı duyarlı saptanan 79 Enterobacterales izolatı BD Phoenix CPO Detect paneli, karbapenem inaktivasyon yöntemi ve konvansiyonel PCR yöntemleri ile incelendi. Konvansiyonel PCR ile 42 izolat blaOXA-48 geni; 16 izolat blaNDM geni ve 7 izolat ise blaOXA-48 ile beraber blaNDM gen bölgesi pozitif olarak saptandı. İzolatların hiçbirinde blaIMP, blaVIM ve blaKPC genlerinde pozitiflik bulunmadı. PCR ile pozitif saptanan toplam 65 izolatın iki tanesi BD Phoenix CPO detect paneli ile negatif saptandı. mCIM testi ile ise 64 tanesi pozitif, yalnızca bir tanesi belirsiz olarak bulundu. Çalışmamız laboratuvarımıza gönderilmiş ardışık örneklerden üretilmiş karbapenem dirençli izolatlar ile planlanan ilk çalışma olduğu için verilerimiz hastanemiz ve bölgemiz açısından epidemiyolojik olarak önem taşımaktadır.