Antibody response after a booster dose of BNT162B2mRNA and inactivated COVID-19 vaccine.

Introduction: The necessity of a booster dose is a matter that has not been as yet illuminated, although it is noted that neutralizing antibody titers decrease over time. We aimed therefore to evaluate antibody titers and seroconversion rates after a booster mRNA vaccine and a booster inactivated vaccine. Methods: A total of 322 participants were divided into three main groups, with two subgroups each, based on their vaccinations and previous infection history. The levels of anti-SARS-CoV-2 Ig-G were analyzed with the Elecsys® Anti-SARS-CoV-2 S assay. Results: The antibody titers showed a linear and significant increase from one vaccine group to the other, displaying progressive changes from group 2IV to group 3IV, and then to group 2IV/mRNA. All of the seronegative participants were in the 2IV(-) subgroup; 93.3% of the participants whose antibody titers were above the upper limit were in the 2IV/mRNA group. Doctors were much more inclined to have a booster dose and mRNA vaccines than nurses. The status of being a doctor increases the rate of having a booster dose 7.8 times; likewise, each annual increase in age increases the rate 1.05 times. Conclusion: Anti-SARS-CoV-2 IgG levels decrease over time. The antibody response rate to only two doses of the inactivated vaccine was meager, so a booster dose is necessary to maintain the effectiveness of inactivated vaccines. The third dose of the vaccine, especially that of the mRNA vaccine, which was found to be much more superior to the inactivated vaccine, should be strongly recommended.

The Impact of Childhood and Parental Vaccination on SARS-CoV-2 Infection Rates in Children.

BACKGROUND: The data on the indirect protection of children via the coronavirus disease 2019 (COVID-19) vaccination of household members are insufficient, and analyses to evaluate the efficacy of COVID-19 vaccines are limited. METHODS: We gathered data on 12,442 patients under the age of 18 regarding the vaccination status of their household members, their vaccine preferences and doses, and their previous history of COVID-19 infection immediately before the patients were administered a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between September 1, 2021 and December 5, 2021. RESULTS: A total of 18.4% (2289) were vaccinated, 91.4% with BNT162b2mRNA vaccine, 8.6% with inactivated COVID-19 vaccine; 48.7% received a single dose, and 51.3% had 2 doses. Real-time RT-PCR positivity proportions were much higher in older children ( P < 0.001) and were higher in children 12 years of age and older [odds ratio (OR), 1.34; 95% confidence interval (CI): 1.21-1.47] compared with others. SARS-CoV-2 infection was significantly lower in the vaccinated group (fully and incompletely) ( P < 0.001). Unvaccinated (OR, 4.88; 95% CI: 3.77-6.13) and incompletely vaccinated children (OR, 1.83; 95% CI: 1.52-2.12) had a higher risk of COVID-19 infection compared with fully vaccinated patients No significant association was found between the COVID-19 real-time RT-PCR positivity rates of patients and the vaccination status or vaccine preferences of household members ( P > 0.05 each). CONCLUSIONS: SARS-CoV-2 infection rates were significantly lower in vaccinated children, especially with mRNA vaccines. The indirect protection of unvaccinated children via the vaccination of household members against COVID-19 seems inadequate. The individual vaccination of children remains crucial.

Potential and promising marker for serious bacterial infections in children: Delta neutrophil index.

AIM: This study aimed to evaluate the usefulness and accuracy of the delta neutrophil index (DNI), an index expressing the number of immature granulocytes as a proportion of the total, as an inflammatory marker in predicting serious bacterial infections (SBIs). METHODS: Paediatric patients admitted to our hospital with fever were divided into four groups: SBI, non-SBI, COVID-19 and control group. White blood cell count, absolute neutrophil count, C-reactive protein and the DNI were recorded, and their accuracy in predicting SBI was evaluated. RESULTS: Mean DNI was 4.96 ± 8.38 in the SBI group (150 patients), 0.67 ± 1.68 in the non-SBI group (397 patients), 0.29 ± 0.99 in the COVID-19 group (112 patients) and 0.14 ± 0.21 in the control group (102 patients). The DNI was significantly higher in the SBI group compared with the non-SBI (P < 0.001); the non-SBI group also had higher levels than the COVID-19 group (P = 0.005). One percent increase in the DNI increased the SBI rate 1.36 times (odds ratio 1.36 (95% confidence interval 1.23-1.49), P < 0.001). Based on the determined cut-off value (>2.5%), the DNI (odds ratio 6.27 (95% confidence interval 3.85-10.21), P < 0.001) significantly predicted SBIs with 90.4% specificity and 47.7% sensitivity. CONCLUSIONS: SBIs in childrenare associated with an increase in DNI levels. Compared to other biomarkers, the DNI had higher specificity in predicting SBIs. The DNI may also be usefulin differentiating bacterial and non-bacterial infections in individualclinical syndromes. Currently, there is no evidence that serum DNI aids indifferentiating COVID-19 and upper respiratory tract infection.

Should a third booster dose be scheduled after two doses of CoronaVac? A single-center experience.

In the 10th month of the pandemic, coronavirus disease 2019 (COVID-19) vaccination was given first to healthcare workers in Turkey after receiving emergency use approval from the Ministry of Health. This study, which was performed at the COVID-19 reference center in Ankara (the capital of Turkey) aimed to evaluate the seroconversion rate of the CoronaVac vaccine. The anti-spike immunoglobulin G response to the two-dose vaccination was retrospectively examined in healthcare workers who had no previous history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The postvaccine seroconversion rate was investigated by measuring the antibody levels of healthcare workers who had received CoronaVac. Vaccination was administered as 600 SU in 28-day intervals. The healthcare workers' anti-SARS-CoV-2 immunoglobulin G levels were used to determine the seroconversion rate 2 months after the second dose of the vaccine. Of the healthcare workers, 22.9% (n = 155) were seronegative. The younger the age of the participant, the higher the level of anti-SARS-CoV-2 immunoglobulin G. Furthermore, anti-SARS-CoV-2 immunoglobulin G levels were much higher in women than men.

Evaluation of COVID-19 vaccine acceptance of healthcare providers in a tertiary Pediatric hospital.

Objective: The aim of this study was to reveal the perceptions of healthcare providers who work in a tertiary children's hospital about domestic and foreign COVID-19 vaccines to determine the frequency of hesitancy toward COVID-19 vaccination prior to its availability in Turkey and to elucidate the reasons for its rejection and distrust.Methods: A questionnaire about COVID-19 vaccination was conducted with 343 healthcare providers, including pediatricians, pediatric nurses, and auxiliary health staff. The questionnaire was conducted online. In the survey, participants were asked about sociodemographic characteristics and opinions on domestic and foreign COVID-19 vaccines, and reasons for vaccine refusal.Results: Women were more likely to be reluctant to get a domestic (p < .001) or foreign (p < .001) COVID-19 vaccine than men. There was a significant relationship between age and vaccine acceptance (p = .01). The younger the age of the healthcare provider, the higher the rate of vaccine hesitancy (r = - 0.25). Years of professional experience were correlated with vaccine acceptance (r = 0,19, p < .05), but vaccine rejection and indecision did not change (p > .05). The factors predicting vaccine acceptance were status as a doctor, more than 10 years of professional experience, and male gender.Conclusion: More than half of the healthcare providers were willing to have a COVID-19 vaccine once available. Indecision rates were found to be high, although rejection rates were not. Status as a doctor, more than 10 years of professional experience, and male gender were factors associated with vaccination intention.

Evaluation of COVID-19 Vaccine Refusal in Parents.

OBJECTIVE: The frequency of vaccine refusal, which is associated with many factors, is increasing worldwide. The aim of this study was to predict the frequency of vaccine refusal against domestic and foreign COVID-19 vaccines and identify the factors underlying refusal. METHODS: A survey consisting of 16 questions about COVID-19 vaccination was conducted either face-to-face or online with 428 parents who agreed to participate in the study. The parents had children who were inpatients or outpatients in the Children's Hospital of Ankara City Hospital. In the survey, parents were asked about family sociodemographic characteristics, opinions on domestic and foreign COVID-19 vaccines, and reasons for vaccine refusal. RESULTS: While 66.1% of parents were reluctant to receive foreign COVID-19 vaccines, only 37.4% were reluctant to receive domestic COVID-19 vaccines. The participants' preference for the domestic vaccine was significantly higher for themselves and their children (P < 0.05). Women were less likely to be willing to receive foreign vaccines than men (P < 0.05). As the education level increased, fewer parents preferred the domestic vaccine for themselves (P = 0.046) and their children (P = 0.005). Both domestic and foreign vaccine acceptability for parents and their children was higher among parents with high anxiety levels regarding COVID-19 infection (P < 0.05). The most common reasons for refusal were anxiety about vaccine side effects, lack of knowledge about the effectiveness of vaccines, and distrust of vaccines originating from abroad. CONCLUSION: Most of the participants were hesitant about COVID-19 vaccines. This study demonstrates that vaccine uptake can be increased by considering the higher preference for domestic vaccines.