Corrigendum: SARS-CoV-2 antibody response after mRNA vaccination in healthcare workers with and without previous COVID-19, a follow-up study from the University Hospital in Krakow, Poland.

[This corrects the article DOI: 10.3389/fimmu.2022.1071204.].

Impact of tooth brushing on oral bacteriota and health care-associated infections among ventilated COVID-19 patients: an intervention study.

BACKGROUND: Up to 48% of ventilated coronavirus disease 2019 (COVID-19) patients develop ventilator-associated pneumonia (VAP) during hospitalization in an ICU. Dysbiotic oral microbiota can colonize the lower respiratory tract and lead to VAP. It is recommended to introduce oral care strategies in the ICU to prevent VAP. In this study, we observed the impact of an oral hygienic protocol with tooth brushing on cultivable oral bacteriota, the incidence of HAI and patient safety among mechanically ventilated COVID-19 patients in an ICU setting. METHODS: In this prospective cohort study, we recruited 56 adult COVID-19 patients who qualified for mechanical ventilation. Patients were divided into 2 groups depending on the oral care procedure: standard and extended oral procedures with tooth brushing. Oral bacteriota samples were taken first within 36 h and after 7 days of intubation. Microorganisms were identified by MALDI/TOF mass spectrometry. bacterial health care-associated infection (HAI) cases were retrospectively analyzed by etiology. A PFGE study was performed for Klebsiella pneumoniae to check for clonal spreading of strains from oral bacteriota samples and HAI cases. RESULTS: We observed significant dysbiosis and a decrease in cultivable oral bacteriota diversity, with a high frequency of potentially pathogenic species, including Acinetobacter baumannii and K. pneumoniae. The HAI incidence rate was high (55.2/1000 patient-days), most commonly of K. pneumoniae and A. baumannii etiologies, which correlated with the presence of A. baumannii and K. pneumoniae in the oral samples. Strains isolated from VAP cases were the same as oral isolates in 8 cases. The procedure with tooth brushing led to less frequent identification of A. baumannii in oral samples (55.6% vs. 5.3%, p = 0.001); however, it did not decrease the incidence of HAIs. CONCLUSIONS: Dysbiotic oral bacteriota is an important source of respiratory pathogens. The introduction of tooth brushing in oral hygiene protocols in an ICU setting was effective in decreasing the extent of oral bacteriota dysbiosis; however, it did not reduce the risk of HAIs or mortality. TRIAL REGISTRATION: 1072.6120.333.2020.

SARS-CoV-2 antibody response after mRNA vaccination in healthcare workers with and without previous COVID-19, a follow-up study from a university hospital in Poland during 6 months 2021.

Introduction: Healthcare workers (HCWs) from the beginning of the pandemic have been at risk of exposure to SARS-CoV-2, so they were vaccinated as first. Objectives: The purpose of the study was to determine the level of antibodies against SARS-CoV-2 in HCWs before and after vaccination with mRNA preparations according to previous COVID- 19. Patients and methods: The HCWs from the University Hospital in Krakow completed two surveys: the baseline survey before receiving the first dose of vaccine (in January 2021) and the follow-up survey in June 2021. In parallel, two blood samples were collected from each participant at baseline and at follow-up. Total anti-SARS-CoV-2 antibody levels were measured using the ECLIA technique. Results: At baseline, 41.1% of HCWs had positive antibody test results, and at follow-up, the vaccinated HCWs had almost 100 times higher antibody levels than the unvaccinated HCWs. Participants under 30 years of age had significantly higher antibody levels in June than older HCWs. Among participants with positive antibody test results in January, HCWs who had experienced asymptomatic COVID-19 had more than five times higher antibody levels in June than HCWs self-reported severe COVID-19. In total, 86.9% of HCWs received Comirnaty or Spikevax. The incidence rate of COVID-19 in the unvaccinated vs. vaccinated group was 13 times higher, 20.5% and 1.9% respectively. Conclusions: These results confirm the effectiveness of vaccination in the prevention of COVID-19 in HCWs. It is worth getting vaccinated regardless of previous infection. Furthermore, vaccination among HCWs under 30 years of age induced more effective antibody production compared to older individuals.

The Seroprevalence of SARS-CoV-2 Antibodies among HealthCare Workers in University Hospital in Krakow before the Era of Vaccination.

BACKGROUND: Knowledge of occupational health is crucial to the safety of healthcare workers in the pandemic period. The aim of our study was the rating of SARS-CoV-2 seroprevalence in connection with selected demographic, social, and organizational factors, as well as the identification of key elements determining the safety of HCWs and patients of the University Hospital in Krakow. METHODS: This was a non-interventional, uncontrolled, open, single-center, cross-sectional online survey on the preparedness for the COVID-19 epidemic and the seroprevalence of medical and non-medical HCWs and students. Serum specimens from 1221 persons were tested using an immunoassay analyzer based on the ECLIA technique for the anti-SARS-CoV-2 antibodies IgM + IgG. RESULTS: The total seroprevalence was 42.7%. In medical students it was 25.2%, while in physicians it was 43.4% and in nurses/midwives it was 48.1%. Of those who tested positive, 21.5% did not know their serological status. The use of personal protective equipment did not have any significant impact on the result of testing for anti-SARS-CoV-2 antibodies. The risk of developing the disease was not influenced by sex, professional work experience, workplace, or intensity of contact with the patient. Among the studied elements, only care of COVID-19 patients significantly increased the risk. The protective factor was starting work between the waves of the epidemic (June-September 2020). CONCLUSIONS: PPE is only one element of infection prevention and control-without other components, such as hand hygiene, it can be dangerous and contribute to self-infection. It is also very important to test healthcare workers. Not being aware of the COVID-19 status of HCWs poses a threat to other staff members, as well as patients and the family and friends of the infected. Thus, extreme caution should be applied when employing respirators with exhalation valves during the COVID-19 pandemic.

The Seroprevalence of SARS-CoV-2 Antibodies among HealthCare Workers in University Hospital in Krakow before the Era of Vaccination

Background: Knowledge of occupational health is crucial to the safety of healthcare workers in the pandemic period. The aim of our study was the rating of SARS-CoV-2 seroprevalence in connection with selected demographic, social, and organizational factors, as well as the identification of key elements determining the safety of HCWs and patients of the University Hospital in Krakow. Methods: This was a non-interventional, uncontrolled, open, single-center, cross-sectional online survey on the preparedness for the COVID-19 epidemic and the seroprevalence of medical and non-medical HCWs and students. Serum specimens from 1221 persons were tested using an immunoassay analyzer based on the ECLIA technique for the anti-SARS-CoV-2 antibodies IgM + IgG. Results: The total seroprevalence was 42.7%. In medical students it was 25.2%, while in physicians it was 43.4% and in nurses/midwives it was 48.1%. Of those who tested positive, 21.5% did not know their serological status. The use of personal protective equipment did not have any significant impact on the result of testing for anti-SARS-CoV-2 antibodies. The risk of developing the disease was not influenced by sex, professional work experience, workplace, or intensity of contact with the patient. Among the studied elements, only care of COVID-19 patients significantly increased the risk. The protective factor was starting work between the waves of the epidemic (June–September 2020). Conclusions: PPE is only one element of infection prevention and control-without other components, such as hand hygiene, it can be dangerous and contribute to self-infection. It is also very important to test healthcare workers. Not being aware of the COVID-19 status of HCWs poses a threat to other staff members, as well as patients and the family and friends of the infected. Thus, extreme caution should be applied when employing respirators with exhalation valves during the COVID-19 pandemic.

Preparedness of Health Care Workers and Medical Students in University Hospital in Krakow for COVID-19 Pandemic within the CRACoV Project.

Backgrounds Health care workers' (HCWs) knowledge of and compliance with personal protective procedures is a key for patients' and personnel safety. The aim of this study was to assess which factors are associated with higher self-evaluations of training on infection prevention and control (IPC) and higher self-assessment of IPC practices used by HCWs regarding COVID-19 in University Hospital in Krakow, Poland, in January 2021. Material and methods This was an online survey on the preparedness for COVID-19 epidemic of medical/non-medical staff and medical students. Questions included in the survey concerned participants' socio-demographic characteristics, hospital staff involvement in the training, knowledge about the hand hygiene, and adherence to IPC measures. Knowledge and Performance Index (K&PI) based on selected questions was constructed for to reflect both subjective (self-evaluation) of preparedness and objective IPC knowledge and skills of HCWs participated in the IPC training. Results A total of 1412 health care workers, including 129 medical students, participated in the study. The largest group, 53.6%, was made up of nurses and paramedics. Age of respondents significantly correlated with knowledge of IPC and with K&PI. The mean age of workers with high K&PI was 42.39 ± 12.53, and among those with low, 39.71 ± 13.10, p < 0.001. 51% UHK workers participated in IPC training, but 11.3% of physicians, 28.8% of other HCWs, and 55.8% of students did not know the IPC standard precaution. Most participants, 72.3%, felt that they had received sufficient training; however, 45.8% of students declined this. There was no correlation between self-reported preparedness and the K&PI, indicating that self-reported preparedness was inadequate for knowledge and skills. Nurses and paramedics assessed their knowledge most accurately. Participants with low K&PI and high subjective evaluation constituted a substantial group in all categories. Students least often overestimated (23.8%) and most often (9.6%) underestimated their knowledge and skills. Conclusions Our study revealed inadequate IPC practice, especially as it refers to the training programme. We confirmed the urgent need of including theory and practice of IPC in curricula of health professions' training in order to provide students with knowledge and skills necessary not only for future pandemic situations but also for everyday work.