Impact of COVID-19 pandemic on emergency and elective surgery. A retrospective observational analysis in Apulia, southern Italy.

Introduction: In Italy, at the beginning of the COVID19 pandemic, only emergency and life-saving elective surgical procedures were allowed with obvious limitations in terms of numbers of operable cases. The aim of our study is to evaluate the performance of surgical activities by Apulian healthcare facilities (Southern Italy) under the pandemic emergency pressure. Methods: The surgical procedures in study were identified via the Apulian regional archive of hospital discharge forms. We used the ICD9 codes in order to define the elective and urgency surgeries in analysis, and we extended our search to all procedures performed from 2019 to 2021. Results: The number of all procedures decreased from 2019 to 2020; the reduction was higher for elective surgery (-43.7%) than urgency surgery (-15.5%). In 2021, an increase compared to 2020 was recorded for all procedures; nevertheless, elective surgeries registered a further slightly decrease compared to 2019 (-12.4%), while a slightly increase was observed for urgency surgeries (+3.5%). No particular variation was observed considering sex and age at surgery of the patients, and days of hospitalization from 2019 to 2021. Conclusions: The impact of COVID19 on Apulian regional health system has been extremely shocked and has required the implementation of strategies aimed at containing the infection and guaranteeing health services as far as possible. A new paradigm of hospital care for SARS-COV-2 patients in the post-emergency phase in Italy is needed, in order to optimize the resources available and to guarantee high standards of quality and efficiency for citizens.

Burden of COVID-19 disease and vaccine coverages in Apulian splenectomized patients: A retrospective observational study.

Splenectomy/asplenia is a condition associated with immune-compromission and specific vaccines are recommended for these patients, including the anti-COVID-19 vaccine. Among the high-risk group for which vaccination was prioritized in Italy, the immunocompromised patients after therapies or treatments were included. The Apulian regional archive of hospital discharge forms was used to define the list of splenectomized Apulian inhabitants, considering data from 2015 through 2020. The overall vaccination status of asplenic patients was assessed via data collected from the Regional Immunization Database. The history of SARS-CoV-2 infection and the infectious disease outcomes were extracted from the Italian Institute of Health platform "Integrated surveillance of COVID-19 cases in Italy". 1219 Apulian splenectomized inhabitants were included; the incidence rate of SARS-CoV-2 infection was 15.0 per 100 persons-year with a proportion of re-infection equal to 6.4%; the proportion of hospitalization was 2.9%, with a case-fatality rate of 2.6%. The vaccine coverage (VC) for the anti-COVID-19 vaccine basal routine was 64.2%, for the first booster dose was 15.4%, and for the second booster dose was 0.6%. A multifactorial approach is needed to increase the vaccination uptake in this sub-group population and to increase the awareness of the asplenia-related risks to patients and health personnel.

Effectiveness of SARS-CoV-2 Vaccines for Short- and Long-Term Immunity: A General Overview for the Pandemic Contrast.

BACKGROUND: The recent COVID-19 pandemic produced a significant increase in cases and an emergency state was induced worldwide. The current knowledge about the COVID-19 disease concerning diagnoses, patient tracking, the treatment protocol, and vaccines provides a consistent contribution for the primary prevention of the viral infection and decreasing the severity of the SARS-CoV-2 disease. The aim of the present investigation was to produce a general overview about the current findings for the COVID-19 disease, SARS-CoV-2 interaction mechanisms with the host, therapies and vaccines' immunization findings. METHODS: A literature overview was produced in order to evaluate the state-of-art in SARS-CoV-2 diagnoses, prognoses, therapies, and prevention. RESULTS: Concerning to the interaction mechanisms with the host, the virus binds to target with its Spike proteins on its surface and uses it as an anchor. The Spike protein targets the ACE2 cell receptor and enters into the cells by using a special enzyme (TMPRSS2). Once the virion is quietly accommodated, it releases its RNA. Proteins and RNA are used in the Golgi apparatus to produce more viruses that are released. Concerning the therapies, different protocols have been developed in observance of the disease severity and comorbidity with a consistent reduction in the mortality rate. Currently, different vaccines are currently in phase IV but a remarkable difference in efficiency has been detected concerning the more recent SARS-CoV-2 variants. CONCLUSIONS: Among the many questions in this pandemic state, the one that recurs most is knowing why some people become more seriously ill than others who instead contract the infection as if it was a trivial flu. More studies are necessary to investigate the efficiency of the treatment protocols and vaccines for the more recent detected SARS-CoV-2 variant.

BNT162b2 mRNA COVID-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection: A Preliminary Report.

In the preregistration trial, data on efficacy of BNT162b2 mRNA vaccine against SARS-CoV-2 infection were not collected. This study aimed to evaluate vaccine effectiveness (VE) against documented infection. Bari Policlinico University Hospital health care workers (HCWs) who completed the vaccination schedule were matched with HCWs who had refused vaccination. VE for documented infection was 61.9% (95% confidence interval [CI], 19.2%-82.0%) 14-20 days after first dose, 87.9% (95% CI, 51.7%-97.0%) 21-27 days after first dose, and 96.0% (95% CI, 82.2%-99.1%) 7 or more days after second dose. Unvaccinated HCWs remain a concern in the context of the pandemic emergency.

More skilled clinical management of COVID-19 patients modified mortality in an intermediate respiratory intensive care unit in Italy.

BACKGROUND: Some studies investigated epidemiological and clinical features of laboratory-confirmed patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) the virus causing coronavirus disease 2019 (COVID-19), but limited attention has been paid to the follow-up of hospitalized patients on the basis of clinical setting and the expertise of clinical management. METHODS: In the present single-centered, retrospective, observational study, we reported findings from 87 consecutive laboratory-confirmed COVID-19 patients with moderate-to-severe acute respiratory syndrome hospitalized in an intermediate Respiratory Intensive Care Unit (RICU), subdividing the patients in two groups according to the admission date (before and after March 29, 2020). RESULTS: With improved skills in the clinical management of COVID-19, we observed a significant lower mortality in the T2 group compared with the T1 group and a significantly difference in terms of mortality among the patients transferred in Intensive Care Unit (ICU) from our intermediate RICU (100% in T1 group vs. 33.3% in T2 group). The average length of stay in intermediate RICU of ICU-transferred patients who survived in T1 and T2 was significantly longer than those who died (who died 3.3 ± 2.8 days vs. who survived 6.4 ± 3.3 days). T CONCLUSIONS: The present findings suggested that an intermediate level of hospital care may have the potential to modify survival in COVID-19 patients, particularly in the present phase of a more skilled clinical management of the pandemic.

Large-scale IgM and IgG SARS-CoV-2 serological screening among healthcare workers with a low infection prevalence based on nasopharyngeal swab tests in an Italian university hospital: Perspectives for public health.

BACKGROUND: Healthcare workers (HCWs) are highly exposed to SARS-CoV-2 infection given their specific tasks. The IgG-IgM serological assay has demonstrated good accuracy in early detection in symptomatic patients, but its role in the diagnosis of asymptomatic patients is uncertain. The aim of our study was to assess IgM and IgG prevalence in sera in a large cohort of HCWs previously subjected to Nasopharyngeal swab test (NST) after accurate risk assessment due to positive COVID-19 patient exposure during an observation period of 90 days. METHODS: 2407 asymptomatic HCWs that had close contact with COVID-19 patients in the period between April 8th and June 7th were screened with NST based on the RT-PCR method. In parallel, they underwent large-scale chemiluminescence immunoassays involving IgM-IgG serological screening to determine actual viral spread in the same cohort. RESULTS: During the 90-day observation period, 18 workers (0.75%) resulted positive for SARS-CoV-2 infection at the NST, whereas the positivity rates for IgM and IgG were 11.51% and 2.37%, respectively (277 workers). Despite high specificity, serological tests were inadequate for detecting SARS-CoV-2 infection in patients with previous positive NST results (IgM and IgG sensitivities of 27.78% and 50.00%, respectively). CONCLUSIONS: These findings indicate a widespread low viral load of SARS-CoV-2 among hospital workers. However, serological screening showed very low sensitivity with respect to NST in identifying infected workers, and negative IgG and IgM results should not exclude the diagnosis of COVID-19. IgG-IgM chemiluminescence immunoassays could increase the diagnosis of COVID-19 only in association with NST, and this association is considered helpful for decision-making regarding returning to work.

Assessing the temporal and cause-effect relationship between myocarditis and mRNA COVID-19 vaccines. A retrospective observational study.

OBJECTIVE: In 2021, the US Centers for Disease Control and Prevention reported increased cases of myocarditis and pericarditis in the United States after mRNA COVID-19 vaccines. Our study aims to estimate the incidence of myocarditis in Apulia (Southern Italy) and the cause-effect relationship between COVID-19 mRNA vaccines and the risk of myocarditis. METHODS: The Apulian regional archive of hospital discharge forms was used to define the cases of myocarditis in Apulia, considering data from 2017 to 2022. The overall vaccination status of patients was assessed via data collected from the Regional Immunization Database. The history of SARS-CoV-2 infection was extracted from the Italian Institute of Health platform. RESULTS: Since 2017, 5687 cases of myocarditis have been recorded in Apulian subjects; the overall incidence described a decreasing trend, with a slight increase in 0-40 years-old subjects. From 2021 to 2022, 2,930,276 doses of COVID-19 mRNA vaccines were administered; a diagnosis of myocarditis after the second dose of the mRNA vaccine was reported for 894 (0.03%) of Apulian inhabitants, with an incidence rate of 17.9 × 1,000,000 persons-month. The multivariate analysis, adjusted for age, sex, underlying medical conditions, and diagnosis of COVID-19, showed that mRNA vaccination is a protective factor for myocarditis even in younger subjects (aOR = 0.4; 95% CI = 0.3-0.5). CONCLUSION: A temporal association between an exposure and an outcome is not equivalent to a causal association. Our study underlines how an approach that considers the other potential causes of myocarditis (primarily COVID-19) and a causality assessment must be prioritized in the study of the topic.

Prevalence of healthcare workers fully vaccinated against hepatitis B without circulating antibodies in Italy and role of age at baseline cycle vaccination: a systematic review and meta-analysis.

INTRODUCTION: Healthcare workers (HCWs) susceptible to hepatitis B represent an important public health concern. National and international guidelines recommend assessing the hepatitis B immune status of all HCWs and possibly vaccinating those found to be seronegative (non-responders). We conducted a meta-analysis to estimate the rate of hepatitis B sero-susceptibility among HCWs in Italy and to explore possible options for the management of non-responders. AREAS COVERED: Nineteen studies, selected from scientific articles available in the Scopus, MEDLINE/PubMed and ISI Web of Knowledge databases between 1 January 2016 and 22 April 2022, were included. The prevalence of HBV-susceptible HCWs was 27.1% (95%CI = 23.2-31.7%). In a comparison by sex (males vs. females) the RR was 1.16 (95%CI = 1.03-1.31), and by full-cycle vaccination period (adolescence vs. infancy) the RR was 0.30 (95%CI = 0.25-0.37). Occupational health screenings for hepatitis B, with subsequent vaccination of non-responders, and exclusion of susceptible HCWs from high-risk settings have been common management strategies. EXPERT OPINION: It is highly probable that a proportion of the next generation of medical students and HCWs will not show circulating IgG on serologic evaluation. Therefore, more targeted efforts are needed to identify these individuals and actively immunize them.

Impact of COVID-19 pandemic on flu vaccine uptake in healthcare workers in Europe: a systematic review and meta-analysis.

INTRODUCTION: Influenza immunization policies in Europe primarily target at-risk and vulnerable subjects. Healthcare workers (HCWs) are a key focus of vaccination campaigns. Our systematic review and meta-analysis aim to evaluate the role of the COVID-19 pandemic on influenza vaccine uptake among HCWs since the 2020/21 influenza season. AREAS COVERED: Fourteen studies were included in the meta-analysis and systematic review, selected from scientific articles available in MEDLINE/PubMed, ISI Web of Knowledge, and Scopus databases between 1 January 2021 and 15 January 2023 The analysis revealed a significant relationship between influenza vaccine uptake and COVID-19 related determinants, such as willingness to receive COVID-19 vaccination, fear of COVID-19, and differentiating between influenza and COVID-19 symptoms (OR = 5.70; 95%CI = 2.08-15.60). Several studies reported higher vaccination coverages in the 2020/21 season compared to previous seasons, with VC values ranging from + 17% to + 38% compared to the 2019/20 season. The included studies identified a shift in HCWs' attitudes toward influenza vaccination, attributed to increased awareness due to the COVID-19 pandemic. EXPERT OPINION: Vaccine hesitancy is common among HCWs in Europe, necessitating mutual strategies across all European countries. So far, mandatory vaccination policies have shown the most potential in achieving high and sustainable influenza vaccination rates among HCWs.

Influenza vaccine coverage in 6months-64 years-old patients affected by chronic diseases: A retrospective cohort study in Italy.

At the beginning of each flu season, the Italian Ministry of Health defines the categories at higher risk of influenza complications, for which vaccination is actively and freely offered. The vaccine coverage (VC) of the influenza vaccine in subjects from 6 months to 64 years of age suffering from diseases that increase the risk of complications from influenza during the 2020-2021 season was evaluated. Our study wants to evaluate the VCs of the influenza vaccine in these subjects during the 2020/2021 season in Apulia. The digital archives relative to the Apulian population were used. A retrospective cohort study design was performed. 484,636 Apulian residents aged between 6 months and 64 years suffered from at least one chronic disease; 139,222 of 484,636 subjects received the influenza vaccine (VC: 28.7%) from October 2020 to January 2021. Considering the single comorbidities, the greatest values are found for pathologies for which major surgical interventions are planned and chronic renal failure/adrenal insufficiency patients, while the worst for chronic liver diseases and pathologies for which major surgical interventions are planned. In any case, it would seem that better VC is achieved in subjects with more than one chronic condition. Influenza vaccination must be promoted as a central public health measure, also because by reducing the burden on hospitals, it can greatly benefit the management of COVID-19 patients. Greater efforts by public health institutions must be implemented in order to achieve better VC in the target categories, including chronic patients.

Attitudes toward influenza vaccination in healthcare workers in Italy: A systematic review and meta-analysis.

Healthcare workers (HCWs) are among the at-risk groups for whom influenza vaccination is strongly recommended. To assess the proportion of Italian HCWs with positive attitudes toward influenza vaccination, we conducted a systematic review of relevant literature and a meta-analysis. Our focus was on the influenza seasons from 2017/18 to 2021/22. The prevalence of favorable attitudes toward vaccination varied, ranging from 12% during the 2017/18 influenza season to 59% in the 2020/21 season. The significant increase in the 2020/21 season can be attributed to adaptations necessitated by the COVID-19 pandemic. During the 2021/22 influenza season, there was a decline in vaccination coverage (37%), likely due to the absence of a robust preventive culture. Various strategies have been employed to enhance HCWs' attitudes to achieve higher vaccination rates, but none of them have demonstrated satisfactory results. Policymakers should consider implementing a policy of mandatory vaccination to ensure elevated vaccination coverage among HCWs.

SARS-CoV-2 Breakthrough Infections in Health Care Workers: An Italian Retrospective Cohort Study on Characteristics, Clinical Course and Outcomes.

BACKGROUND: The aim of this study was to determine the characteristics, clinical course and outcomes of COVID-19 breakthrough infections (BIs) among healthcare workers (HCWs) of an Italian University Hospital. METHODS: A retrospective observational study was conducted on 6111 HCWs, from January 2021 to February 2022. The study population was offered the full vaccination with BNT162b2 mRNA COVID-19 vaccine. To allow return to work after BI, the protocol required one negative nasopharyngeal RT-PCR swab followed by a medical examination to assess the HCW's health status. Laboratory tests, instrumental tests and specialist evaluations were carried out if necessary. RESULTS: The cases of BIs observed numbered 582 (9.7%). The frequency of BIs was significantly higher in females than in males (67% vs. 33%; p = 0.03), and in nurses than in all other professional categories (p = 0.001). A total of 88% of the HCWs affected by BI were still symptomatic after the negative swab. None of the instrumental tests carried out showed any new findings of pathological significance. All cases showed progressive disappearance of symptoms, such that no cases of long COVID and no hospitalization or deaths were recorded. CONCLUSIONS: Our results confirm that SARS-CoV-2 infections occur even after a full vaccination course; however, the clinical course is favorable and severe outcomes are reduced.

Impact of a Pro-Active Infectious Disease Consultation on the Management of a Multidrug-Resistant Organisms Outbreak in a COVID-19 Hospital: A Three-Months Quasi-Experimental Study.

BACKGROUND: Antimicrobial and diagnostic stewardship (AS/DS) principles are crucial for the management of multidrug-resistant organisms (MDROs) infections. We evaluated the impact of a pro-active Infectious Disease (ID) consultation on the mortality risk of patients during an MDROs outbreak in a COVID-19 hospital. METHODS: A quasi-experimental study was performed in a dedicated COVID-19 hospital, including patients with suspected/confirmed infection and/or colonization by MDROs, which were managed as follows: (i) according to the standard of care during the pre-phase and (ii) in collaboration with a dedicated ID team performing a pro-active bedside evaluation every 48-72 h in the post-phase. RESULTS: Overall, 112 patients were included (pre-phase = 89 and post-phase = 45). The AS interventions included the following: therapy optimization (33%), de-escalation to narrow the spectrum (24%) or to lessen toxic drugs (20%), and discontinuation of antimicrobials (64%). DS included the request of additional microbiologic tests (82%) and instrumental exams (16%). With the Cox model, after adjusting for age, sex, COVID-19 severity, infection source, etiological agents, and post-phase attendance, only age predicted an increased risk of mortality, while attendance in the post-phase resulted in a decreased risk of mortality. CONCLUSIONS: Implementation of AS and DS intervention through a pro-active ID consultation may reduce the risk of 28-day mortality of COVID-19 patients with MDROs infections.

Waste Management and the Perspective of a Green Hospital-A Systematic Narrative Review.

The concept of a "green hospital" is used in reference to a hospital that includes the environment as part of its quality services and one that pays attention to the sustainable design of buildings. Waste disposal represents a potential risk for the environment; therefore, waste collection from healthcare centers is a key environmental issue. Our study aims to systematically review the experiences acquired in worldwide nosocomial settings related to the management of healthcare waste. Nineteen studies, selected between January 2020 and April 2022 on Scopus, MEDLINE/PubMed and Web of Science databases were included in our systematic narrative review. Operating room and hemodialysis activities seem to be the procedures most associated with waste production. To deal with waste production, the 5Rs rule (reduce, reuse, recycle, rethink and research) was a common suggested strategy to derive the maximum practical benefit while generating the minimum amount of waste. In this context, the COVID-19 pandemic slowed down the greening process of nosocomial environments. Waste management requires a multifactorial approach to deal with medical waste management, even considering the climate change that the world is experiencing. Education of health personnel and managers, regulation by governmental institutions, creation of an "environmental greening team", and awareness of stakeholders and policymakers are some of the measures needed for the greening of healthcare facilities.

Two years of on-site influenza vaccination strategy in an Italian university hospital: main results and lessons learned.

Although the vaccination of healthcare workers (HCWs) is considered essential for preventing influenza circulation in the hospital setting, vaccination coverage (VC) in this group remains low. Among the reasons cited by HCWs is a lack of time to attend the vaccination clinic. For the 2018/2019 influenza season, active (on-site) influenza vaccination was offered directly in 44 operative units (OUs) of the Bari Policlinico hospital (50 OUs, 3,397 HCWs). At the same time, the hospital granted the HCW access to the vaccination clinic during October and December 2018. VC achieved among HCWs of Bari Policlinico during the 2018/2019 influenza season was then analyzed, and the results compared with those of the 2017/18 season. During the 2018/19 season, VC was 20.4% (n = 798) and thus higher than the 14.2% of the 2017/18 season (+6.2%). The highest VC was among physicians (33.4%), followed by other HCWs (23.8%), auxiliary staff (8.6%), and nurses (7.2%). Overall, 284 (36.5%) HCWs were vaccinated at on-site sessions. Multivariate analysis showed that vaccination uptake was associated with male gender and with work in OU where vaccination was actively offered. On the other hand, being a nurse or auxiliary staff member and working in the surgical area were deterrents. Although VC remained unsatisfactory, active on-site vaccination proved to be an important strategy to improve vaccination compliance, increasing 44% compared to the previous season. Nonetheless, mandatory vaccination directed by public health institutions may be the only way to reach a minimum level of coverage.

Organizational wellbeing: A model of a new Apulian COVID-19 designated hospital.

Background: Work environment characteristics have an important impact on organizational wellbeing in health care facilities. In the Apulia Region, a new COVID-19 hospital was planned, designated and built in a few weeks for the treatment of patients infected with SARS-CoV-2. To our knowledge, this hospital, together with "Fiera Hospital" in Milan, are two of the few buildings worldwide that have been converted into new health care facilities with intensive care center units to treat COVID-19 patients, and this is the first study assessing organizational wellbeing in a newly designated COVID-19 hospital. Aims: To detect and assess the strong points, criticality, and perceptions of wellbeing/discomfort of health care workers engaged in the management of the current health emergency. Method: The study was conducted on 188 health care workers, with the "Multidimensional Organizational Health Questionnaire." Results: We found an overall positive level of organizational wellbeing. The more positive dimensions were "Collaboration between colleagues," "Organizational efficiency" and "Room Comfort." Conflict situations in the workplace were poorly perceived. A very low rate of absenteeism from work was also observed. Conclusions: Our results show the effectiveness of the organizational model adopted in the management of the COVID-19 hospital, especially in view of the work and emotional overload of the personnel called to face the epidemiological emergency on the frontline, which did not adversely affect the psychophysical conditions of the workers. The success of this model is related to the coexistence of all levels of care required during any type of health emergency in a single structure, paying particular attention to the architectural, functional, and procedural aspects of health care and to the so-called "humanization" of care.

Medium-to-Long-Term Immunogenicity of BNT162b2 mRNA COVID-19 Vaccine: A Retrospective Cohort Study.

To deal with the COVID-19 pandemic, a mass vaccination campaign was started in European countries on 27 December 2020. The first vaccine available to immunize healthcare workers (HCWs) was the BNT162b2 mRNA COVID-19 vaccine. While many studies have shown a high antibody response after the second vaccine dose, antibody persistence over the medium-to-long term has yet to be evaluated. The medium-to-long-term persistence of anti-SARS-CoV-2 antibodies was determined in a sample of fully vaccinated HCWs at Bari Policlinico General Hospital, Italy. This is a observational cohort study. HCWs who completed the immunization basal cycle were screened for anti-SARS-CoV-2 IgG on days 15, 30, 60, 90, and 120 after the second vaccine dose. At each time point, >99% of the screened HCWs were seroprotected. While the geometric mean titer initially declined over time, by 60 days the titer had stabilized. Older subjects seem to lose IgG faster than younger ones. The immunogenicity conferred by the vaccine provides further evidence that it is an essential weapon in efforts to bring the COVID-19 pandemic under control. Accordingly, strict measures should be implemented, ranging from the mandatory vaccination of HCWs to strong incentives aimed at achieving vaccination of the large majority of the overall population.

Immune response to one dose of BNT162b2 mRNA Covid-19 vaccine followed by SARS-CoV-2 infection: An Italian prospective observational study.

INTRODUCTION: A mass vaccination campaign against SARS-CoV-2 was initiated in European countries on December 27, 2020. This study compared the antibody response in a sample of healthcare workers (HCWs) who, after the first dose of the BNT162b2 mRNA vaccine, were infected with SARS-CoV-2 (infection group) with the response in a control group of HCWs immunized with two doses (vaccine group). METHODS: This two-arm observational cohort study was carried out using routine health surveillance data obtained from HCWs at Bari Policlinico General Hospital (Italy). The antibody response was determined infection group and vaccine group. RESULTS: Among the 100 HCWs, 25 (25.0%) were in the infection group and 75 (75.0%) in the full-vaccine group. At the serological evaluation, all of the HCWs tested positive, with a geometric mean titer (GMT) of 7106.8 (95 %CI = 5628.5-8973.4) and a statistically significant difference (p < 0.0001) between the infection group (GMT = 2139.7; 95 %CI = 1310.4-3493.6) and the vaccine group (GMT = 10603.6; 95 %CI = 8698.0-12926.8). DISCUSSION: Our results shed light on the vaccine response of individuals in different risk categories. It also emphasizes the need for the continued use by HCWs of PPE and good practices during the window between the first and second anti-SARS-CoV-2 vaccinations.

Antispike Immunoglobulin-G (IgG) Titer Response of SARS-CoV-2 mRNA-Vaccine (BNT162b2): A Monitoring Study on Healthcare Workers.

The secretion of IgG SARS-CoV-2 antispike antibodies after vaccination with BNT162b2 and the protection represent the response of the human organism to the viral vector symptomatic infections. The aim of the present investigation was to evaluate the immune reaction in health workers of the Polyclinic of Bari to identify the relationship of antispike titers with blood type, sex, age, and comorbidities. This prospective observational study (RENAISSANCE) had as its primary endpoint the assessment of serologic response to BNT162b2 at three blood titers: the first at 60 days after the second dose (3 February 2021); the second titer at 75 days after the first titer; and the third titer at 130 days after the second titer. Out of 230 enrolled staff members, all responded excellently to the mRna Pfizer (BNT162b) vaccine. Only one patient, 40 days after the second dose (3 February 2021), was positive on the swab control performed on 15 March 2021, although completely asymptomatic, and was negative on the subsequent molecular swab performed on 30 March 2021. All the patients responded to the mRNA Pfizer (BNT162b) vaccine with an antispike IgG level above 500 BAU/mL at the first antispike protein essay (60 days after the second dose on 3 April 2021); at the second titer (75 days after the first titer on 20 June 2021), 4 (1.7% of 230 enrolled) patients showed an antispike IgG level under 500 BAU/mL; at the third titer (130 days after the second titer on 30 June 2021, which means 9 months after the second dose), 37 (16.1% of 230 enrolled) patients showed an antispike IgG level under 500 BAU/mL. The data analysis demonstrated that patients belonging to blood group 0, regardless of their rhesus factor, showed the strongest level of antibodies compared to the other groups. No dependency was found between low antibodies level and sex or age. Molecular swab controls were performed every 15th of the month continuously. However, the enrolled patients' activity was at high risk because they carried out medical activities such as dental and surgical as well with droplets of water vaporized by the effect of turbines, piezosurgery. The vaccination campaign among health workers of the Policlinico of the University of Bari "Aldo Moro" led to an excellent serological response and the complete absence of COVID-19 incident cases, so the antibody response was excellent. The COVID-19 vaccine booster shot should be administered after 9 months and not without prompt antispike titer detection to assess if any sign of waning immunity is present in that specific patient.