Effectiveness of the BNT162b2 and the CoronaVac vaccines and boosters in healthcare workers.

The evidence on the waning protection of COVID-19 vaccines has been reviewed by the World Health Organization and has led to consideration of the need for booster doses. This study aimed to evaluate vaccine effectiveness against COVID-19, and the COVID-19 infections among healthcare workers who received various types (inactive or m-RNA) and doses (2 to 4 doses) of the COVID-19 vaccine. The study was conducted with a total of 3,009 healthcare workers between August 1 and November 30, 2021 at a university hospital. Six different vaccination statuses were evaluated in the study. The effectiveness for COVID-19 infection, after adjusting for age, sex, and position, was highest in those who received two doses of CoronaVac and two doses of BNT162b2 (89.3%, 95% CI 72.2-95.9%) and was lowest in those who received two doses of CoronaVac (29%, 95% CI - 8-53%). The adjusted effectiveness of two doses of CoronaVac for COVID-19 infection was not significant (21.0%, 95% CI - 20.7-48.3%) but increased significantly with a booster dose of CoronaVac or BNT162b2. One or two doses of the BNT162b2 booster demonstrated higher effectiveness in comparison to a single dose of the CoronaVac booster. These results indicate the need for a booster dose, and heterologous boosting with BNT162b2 may be a better option for higher effectiveness for those who received two doses of CoronaVac. Future studies should evaluate the need for further booster doses and their long-term effects.

Homologous or heterologous COVID-19 vaccine schemes: comparison of immune responses and side effects.

Real-life data are needed regarding the appropriate time and selection of vaccination strategies, homologous or heterologous. We aimed to compare neutralizing antibody levels and side effects in different vaccination schemes. The study included 310 Health Care Workers (HCWs) vaccinated with 5 different schemes. Antispike/RBD IgG levels were measured between 28 and 60 days after the last dose. Side effects in participants were recorded, and pharmacovigilance records were reviewed from the outpatient vaccine clinic. Mean age of the participants was 38 ± 11 years of whom 226 (72.9%) were female, and 84 (27.1%) were male. After booster doses, increasing antibody levels were detected in all groups. Mean antibody levels were detected to be statistically lower in 3 doses of inactivated vaccines group. The side effects were no significant difference between groups. Booster dose administration with mRNA vaccines stands out as the most accurate strategy for those at risk of contracting severe COVID-19 and HCWs caring for this population.

Waning immunity to inactive SARS-CoV-2 vaccine in healthcare workers: booster required.

AIMS: Despite high vaccination rates, increasing case numbers continue to be reported with the identification of new variants of concern, and the issue of durability of the vaccine-induced immune response remains hot topic. Real-life data regarding time-dependent immunogenicity of inactivated COVID-19 vaccines are scarce. We aimed to investigate the changes in the antibody at the different times after the second dose of the CoronaVac vaccine. METHODS: The study included 175 HCWs vaccinated with inactive CoronaVac (Sinovac Life Sciences, China) SARS-CoV-2 vaccine in two doses. Anti-spike/RBD IgG levels were measured first, third, and sixth months after the second dose. Chemiluminescent microparticle immunoassay (IgG II Quant test, Abbott, USA), which is 100% compatible with plaque reduction neutralization test, was used. RESULTS: Mean age of the participants was 38 ± 11.23 years (range between 22 and 66) of whom 119 (63.9%) were female, and 56 (32%) were male. Dramatic reductions were demonstrated in median antibody levels particularly in the infection-naïve group, comprising 138 HCWs compared to those with prior history of COVID-19 infection (n = 37) (p < 0.001). There was no difference between the two groups in terms of age, gender, blood groups, BMI, and comorbid diseases. CONCLUSIONS: While antibody positivity remained above 90% in the 6th month after two doses of inactivated vaccine in HCWs, the median titers of neutralizing antibodies decreased rapidly. The decrease was more rapid and significant in those with no history of prior COVID-19 infection. In this critical phase of the pandemic, where we are facing the dominance of the Omicron variant after Delta, booster doses have become vital.

Changing Bacterial Etiology and Antimicrobial Resistance Profiles as Prognostic Determinants of Diabetic Foot Infections: A Ten-Year Retrospective Cohort Study.

Background: In this single-center study, we analyzed a retrospective cohort of patients with diabetic foot infections (DFIs) between 2011 and 2020. Patients and Methods: The first and second five-year periods were compared. A poor prognosis was defined as a primary composite end point including re-infection, major amputation, or mortality at six months. Results: A total of 484 patients were enrolled. Overall, 269 patients had the primary composite end point. A substantial decrease was detected in the second five-year period in terms of re-infection (n = 132, 66.0% vs. n = 68, 23.9%; p < 0.001) and mortality (n = 22, 11.0% vs. n = 7, 2.5%; p < 0.001). A total of 798 micro-organisms were isolated from 484 patients. A substantial increase was detected in polymicrobial infections (48.5% vs. 65.1%; p = 0.001) as well as Streptococcus spp. (2.5% vs. 9.2%; p = 0.003), Corynebacterium spp. (9.5% vs. 22.9%; p < 0.001), and extended-spectrum ß-lactamase (ESBL) producing Escherichia coli (3.0% vs. 12.7%; p < 0.001) in the second five-year period, whereas the prevalence of multi-drug-resistanct (MDR) Pseudomonas aeruginosa (17.0% vs. 10.2%; p = 0.029) and carbapenem-resistant Acinetobacter baumannii (7.5% vs. 2.8%; p = 0.017) decreased. Multivariable regression analysis revealed that MDR Pseudomonas aeruginosa (odds ratio [OR], 1.917; 95% confidence interval [CI], 1.074-3.420; p = 0.028) and carbapenem-resistant Acinetobacter baumannii (OR, 3.069; 95% CI, 1.114-8.453; p = 0.030) were independent predictors for poor prognosis. Conclusions: This 10-year cohort study provides reassuring information about the changing epidemiology of DFIs and the prognostic determinants in patients with DFIs.

Heterologous booster COVID-19 vaccination elicited potent immune responses in HCWs.

The objective of our study was to evaluate the antibody responses of health care workers (HCWs) who were vaccinated with booster dose BNT162b2 6 months after 2 doses of the CoronoVac vaccine. The study included 318 HCWs vaccinated with inactive CoronaVac SARS-CoV-2 vaccine in 2 doses. Anti-spike/RBD IgG levels were measured immediately before and 1 month after the booster dose. In the sixth month after CoronaVac vaccination, the median of antibody levels of 1212.02 AU/ML, while it was 9283 AU/mL after BNT162b2 vaccination. IgG antibody titers of over 1050 AU/mL (which is equivalent to 1:80 dilution in the plaque reduction neutralization test) were detected in HCWs 15.09% and 97.8%, respectively. Our results showed that antibody titers increased 8-fold after the booster dose. We believe that the administration of the mRNA vaccine as a booster dose can provide more effective protection against COVID-19 infection, especially in individuals with risk factors.

Waning effectiveness of CoronaVac in real life: A retrospective cohort study in health care workers.

BACKGROUND: Real-world studies showed varying levels of effectiveness of CoronaVac vaccine against COVID-19 disease. This study aimed to assess the association between the vaccination with CoronaVac and the COVID-19 infections among the health care workers in a university hospital and to determine the vaccine effectiveness against COVID-19 in a period when alpha variant was dominant. METHODS: This retrospective cohort study was conducted in a university hospital in Istanbul, Turkey employs 4067 health care workers. The follow-up period was defined as starting 14 days after receiving the second dose for fully vaccinated group. Health care workers were censored when have a positive PCR test result or at the end of the study. Unvaccinated health care workers were censored if they receive any COVID-19 vaccine doses. The incidence rate ratio and Cox regression were used to estimate the unadjusted and adjusted effectiveness of the vaccine. FINDINGS: Seventy-one percent of the health care workers were fully vaccinated whereas 29% percent did not receive any doses. The incidence rate of SARS-CoV-2 infection was 133.7 vs 70.7 per 100.000 person-days in the unvaccinated and fully vaccinated groups, respectively. The unadjusted effectiveness against COVID-19 infection was 47% (95% CI 31-59%) whereas adjusted effectiveness was 39% (95% CI 20-64%). INTERPRETATION: This real life study conducted in health care workers demonstrated that the effectiveness of two doses of the CoronaVac vaccine (39%) was lower than that determined in clinical trials. Due to reduce in protection over time or against variants, booster doses may be needed.

Inactive SARS-CoV-2 vaccine generates high antibody responses in healthcare workers with and without prior infection.

BACKGROUND AND OBJECTIVES: Healthcare workers (HCWs) were among the first groups to be vaccinated in Turkey. The data to be obtained by the vaccination of HCWs would guide wide spread vaccination programs. MATERIALS AND METHODS: The study included 330 HCWs working at Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty Hospital and vaccinated with inactive CoronaVac (Sinovac Life Sciences, China) SARS-CoV-2 vaccine in two doses (28 days apart). Anti-Spike /RBD IgG levels were measured 14 days after the first dose and 28 days after the second dose. Chemiluminescent microparticle immunoassay (CMIA) (ARCHITECT IgG II Quant test, Abbott, USA), which is 100% compatible with plaque reduction neutralization test (PRNT), was used. RESULTS: Of the participants, 211 (63.9%) were female, 119 (36.1%) were male, and mean age was 39.6 ± 7.7 years. In those without prior COVID-19 history; (n = 255) antibody positivity was detected as 48.2% (95% CI: 42.1-54.3) 14 days after the first dose of vaccine, and 99.2% (95% CI: 98.1-100) at day 28 after the second dose. Antibody titers were significantly lower in patients with hypertension (p = 0.011). In those with prior history of COVID-19 (n = 75); both the antibody positivity rates after the first vaccine (48.2% vs 100%, p = 0.000) and the anti-spike/RBD antibody levels after the second vaccine (with a ≥ 1050 AU/mL titer equivalent to PRNT 1/80 dilution) was significant than infection-naive group (25.9% vs. 54.7%, p = 0.000). Antibody positivity after two doses of vaccination for all study group was 99.4% (95% CI: 98.6-100). CONCLUSIONS: Two doses CoronaVac produce effective humoral immunity in HCWs. Antibody response is significantly higher in those with prior history of COVID-19 than infection-naive group. Given no significant benefit of the second dose, a single shot of vaccination may be sufficient for those with prior history of COVID-19. Monitoring humoral and cellular immune responses, considering new variants, is required to validate this approach.

SARS-CoV-2 IgG Antibody Levels After Inactivated Vaccine (CoronaVac) among Elderly.

We aimed to describe the antibody response against SARS-CoV-2 after inactivated COVID-19 vaccine in elderly individuals. SARS-CoV-2 IgG levels were measured in the blood samples of 126 volunteers over the age of 60. The antibody positivity rate was 42.8% after the first dose and 96.8% after the second dose of the vaccine. The median antibody titers after two vaccine doses were 561.3AU/mL and 43AU/mL, respectively(p<0.001). After vaccination, 22.2% of the participants had antibodies equivalent to 1:80 dilutions in plaque reduction neutralization test (PNRT). We believe that the booster dose is needed to continue the protective immune response in especially elderly groups.

COVID-19 Vaccine Hesitancy in Healthcare Personnel: A University Hospital Experience.

Healthcare workers are among risk groups in the COVID-19. Even if they are not infected with the disease, they witness the effects of the pandemic. The aim of the study is to determine the factors affecting COVID-19 vaccination status and reasons for vaccine hesitancy of healthcare personnel in our hospital. Firstly, the vaccination status and demographic characteristics of all healthcare personnel was evaluated. After that, a survey was applied to 408 vaccinated and 297 nonvaccinated personnel. Within the first month after the beginning of vaccination, 66% of 3937 healthcare personnel received a COVID-19 vaccine. The number of vaccinated personnel was higher among doctors, master graduates or higher educational levels and basic science-laboratory unit workers. In the surveyed group, being under the age of 50 (OR:1.85), being nondoctor healthcare personnel (nurse/midwife OR:1.78, administrative personnel OR:3.42, patient attendant/cleaning staff OR:4.11, security guard/other OR:2.96), having had the disease before (OR:2.36), not having the flu vaccine (OR:3.24) and hesitancy about other vaccines (OR:6.61) were found to be independent risk factors for not having a COVID-19 vaccine or having it late. The three most common reasons for not getting vaccinated were doubt on the efficacy of the vaccine, distrust of its content, and fear of side effects. Taking steps by considering the main factors of hesitancy among healthcare personnel will increase the vaccine acceptance.