A histopathological and epidemiological study of urothelial carcinoma at a tertiary care centre in Peshawar, Pakistan.

Bladder cancer is the ninth leading cause of death worldwide and 14th leading cause of death in Pakistan. The objective of this study was to determine the frequency of urothelial carcinoma in various age groups, its gender distribution, and grades. A total of 131 cases of urothelial carcinoma, received at Department of Pathology, Peshawar Medical College, Peshawar, between January 2017 to December 2022, were included in the study; of them 107 (81.6%) were males while 24 (18.3%) were females with a mean age of 62±13 years. The most common histological subtype was papillary urothelial carcinoma in 117(89.3%) cases, followed by Squamous and Glandular in 5(3.8%) cases. Majority of the urothelial carcinoma with high grade showed a statistically significant relation with muscle invasion 38 (50.66%). Males were four times more likely to have urothelial carcinoma while older age groups were more likely to have high grade urothelial carcinoma.

Black soldier fly, Hermetia illucens as a potential innovative and environmentally friendly tool for organic waste management: A mini-review.

The application of black soldier fly (BSF), Hermetia illucens based technology to process organic wastes presents a practical option for organic waste management by producing feed materials (protein, fat), biodiesel, chitin and biofertilizer. Therefore, BSF organic wastes recycling is a sustainable and cost-effective process that promotes resource recovery, and generates valuable products, thereby creating new economic opportunities for the industrial sector and entrepreneurs. Specifically, we discussed the significance of BSF larvae (BSFL) in the recycling of biowaste. Despite the fact that BSFL may consume a variety of wastes materials, whereas, certain lignocellulosic wastes, such as dairy manure, are deficient in nutrients, which might slow BSFL development. The nutritional value of larval feeding substrates may be improved by mixing in nutrient-rich substrates like chicken manure or soybean curd residue, for instance. Similarly, microbial fermentation may be used to digest lignocellulosic waste, releasing nutrients that are needed for the BSFL. In this mini-review, a thorough discussion has been conducted on the various waste biodegraded by the BSFL, their co-digestion and microbial fermentation of BSFL substrate, as well as the prospective applications and safety of the possible by-products that may be generated at the completion of the treatment process. Furthermore, this study examines the present gaps and challenges on the direction to the efficient application of BSF for waste management and the commercialization of its by-products.

SARS-CoV-2: big seroprevalence data from Pakistan-is herd immunity at hand?

PURPOSE: Seroprevalence surveys from different countries have reported SARS CoV-2 antibodies below 20% even in the most adversely affected areas and herd immunity cannot be predicted till more than half of the population gets the disease. The purpose of this survey was to estimate the magnitude of community-based spread of the infection, associated immunity, and the future prospects and proximity to a 'herd community'. METHODS: The study was undertaken as a cluster randomized, cross-sectional countrywide survey. This largest community-based seroprevalence data of SARS-CoV-2 were collected between 15th and 31st July, 2020 from seven randomly selected cities belonging to the three most populous provinces of Pakistan. The FDA approved kit of ROCHE was used for detection of SARS-CoV-2 antibodies. RESULTS: Serum samples of 15,390 participants were tested for SARS CoV-2 antibodies with an overall seroprevalence of 42.4%. The seroprevalence ranged from 31.1% to 48.1% in different cities with the highest in Punjab province (44.5%). In univariable analysis, the odds of seropositivity was higher in men compared to women (OR: 1.10, 95% CI: 1.01-1.19, P < 0.05). In multivariable analysis, the risk of being seropositive was lower (OR 0.72, 95% CI: 0.60-0.87, P < 0.01) in younger group (≤ 20 years) than in those aged above 60 years. CONCLUSION: The study concluded that despite a reasonable seroprevalence, the country is yet to reach the base minimum of estimations for herd immunity. The durability of immunity though debated at the moment, has shown an evidenced informed shift towards longer side.

Enhanced bioconversion of dairy and chicken manure by the interaction of exogenous bacteria and black soldier fly larvae.

Generation of insects' biomass from lignocellulose rich organic wastes is of significant challenges in reducing the environmental impact of wastes and in sustaining feed and food security. This research looked at the effects of lignocellulotic exogenous bacteria in the black soldier fly (BSF) organic waste conversion system for biomass production and lignocellulose biodegradation of dairy and chicken manures. Six exogenous bacteria were investigated for cellulolytic activity with carboxymethyl cellulose and found that these tested bacterial strains degrade the cellulose. In this study; a co-conversion process using Hermetia illucens larvae to convert the previously studied best mixing ratio of dairy manure (DM) and chicken manure (CHM) (2:3) and cellulose degrading bacteria was established to enhance the larval biomass production, waste reduction and manure nutrient degradation. BSF larvae assisted by MRO2 (R5) has the best outcome measures: survival rate (99.1%), development time (19.0 d), manure reduction rate (48.7%), bioconversion rate (10.8%), food conversion ratio (4.5), efficiency of conversion of ingestion (22.3), cellulose (72.9%), hemicellulose (68.5%), lignin (32.8%), and nutrient utilization (protein, 71.2% and fat, 67.8%). By analyzing the fiber structural changes by scanning electron microscopy and Fourier-transformed infrared spectroscopy (FT-IR), we assume that exogenous bacteria assist the BSF larvae that trigger lead to structural and chemical modification of fibers. We hypothesized that these surface and textural changes are beneficial to the associated gut bacteria, thereby helping to larval growth and reduce waste. The finding of the investigation showed that enhanced conversion of DM and CHM by BSF larvae assisted with lignocellulotic exogenous bacteria could play key role in the manure management.

Hyperlipidemia and hyper glycaemia in Breast Cancer Patients is related to disease stage.

OBJECTIVE: The study was designed to determine the hyperlipidemia in breast cancer of patients at disease presentation, without any treatment and to correlate these variations with disease stage. METHODS: This cross sectional study was conducted at Liaquat National teaching hospital in Karachi from 2006 to 2011, Age and family history of 208 breast cancer patients with infiltrating Ductal Carcinoma were compared with 176 matched control subjects. Married females were selected, with children and short breast feeding period. Cancer stage I-III was considered for the study and patients were grouped on the basis of Tumor grade, Tumor size, lymph node metastasis and disease free survival. Disease staging was based on tumor size and lymph node metastasis. Biochemical estimations included variations in random blood glucose level and lipid profile. RESULTS: Lipid profile and random blood glucose level were found significantly high (p<0.05) compared to control subjects. Hyperlipidemia was significantly high in breast cancer patients with lymph node metastasis. On increase in tumor grade I to II, increase in total cholesterol (4%), LDL-cholesterol 23% and 11% increase in triglycerides was observed. On Tumor size increase from ≤2 to 2.5cm, increase observed in blood random glucose level was (4%), total cholesterol (1.7%) triglycerides (2%) and LDL (3%) whereas HDL was (2%) low. These variations remain insignificant on further increase in tumor size and grade. CONCLUSION: Study suggests that variation in lipid profile and blood random glucose level is associated with disease stage. No independent correlation of hyperlipidemia and hyperglycemia was developed with disease free survival.

Intermediate- and long-term follow-up of device closure of patent arterial duct with severe pulmonary hypertension: factors predicting outcome.

BACKGROUND: In patients with large patent arterial ducts and severe pulmonary hypertension, the natural history of progression of pulmonary hypertension is very variable. Whether to close or not to close is often a difficult decision, as there are no established haemodynamic parameters predicting reversibility. OBJECTIVES: The objectives of this study were to evaluate the results of device closure of large patent arterial ducts with severe pulmonary hypertension after 2 years of age and to determine haemodynamic variables associated with its regression during long-term follow-up. METHODS: A total of 45 patients, with median age of 10 (2-27) years, with large patent arterial ducts and severe pulmonary hypertension, were considered. Haemodynamic variables were assessed in air, oxygen, and after occlusion. The follow-up was performed to assess regression of pulmonary hypertension. RESULTS: Device closure was successful in 43 (96%) patients. Pulmonary artery systolic and mean pressures decreased from 79 to 67 mmHg and from 59 to 50 mmHg, respectively (p25% (both in oxygen) (p=0.007). CONCLUSIONS: Device closure of large patent arterial ducts with severe pulmonary hypertension is safe and effective. Pulmonary vascular resistance index and systolic and mean pulmonary artery pressures in oxygen are the key prognostic variables predicting regression of pulmonary hypertension.

CHANGING CLINICAL PROFILE OF ACUTE RHEUMATIC FEVER AND RHEUMATIC RECURRENCE.

BACKGROUND: Clinical profile of acute rheumatic fever and rheumatic recurrence seems to have changed in countries where rheumatic fever is still endemic. The objectives of this study were to compare clinical profile and outcome of patients suffering initial and recurrent episodes of acute rheumatic fever in children. METHODS: This prospective study was conducted in two tertiary care hospitals from January to June 2011. The diagnosis was based on the modified Jones criteria. Sixty children were included in the study, 15 having first episode of rheumatic fever and 45 with rheumatic recurrence. The severity of carditis was assessed by Clinical and echocardiography means: RESULTS: Carditis was the commonest presentation in both first (80%) and recurrent attacks (100%). Arthritis was seen in 60% of children with first episode and in 26.7% with recurrence. The frequency of subcutaneous nodules, invariably associated with carditis, was very high (33.3% in the first and 48.3% in recurrent episodes). Carditis was generally mild during first episode (53.3%) and severe with rheumatic recurrence (55.6%). There was no death in either group. One patient with severe mitral regurgitation and rheumatic recurrence underwent mitral valve repair for intractable heart failure. CONCLUSION: Clinical profile of rheumatic recurrence and acute rheumatic fever has changed. Rheumatic recurrence is associated with severe carditis. Carditis is more common than arthritis even in the first attack. Sub-cutaneous nodules are a frequent finding invariably associated with carditis.

Antidiarrhoeal, Anti-inflammatory and analgesic activities of Symplocos racemesa roxb. Bark.

The antidiarrheal activity of the drug Symplocos racemosa was performed in-vivo on isolated rabbit intestine. The effects of crude extract and fractions were observed at different doses. The overall response of the crude extract on isolated tissue of rabbit intestine was decreased in the tone of smooth muscle. Further studies were carried out on different fractions (ethylacetate, chloroform, n-butanol and aqueous) of crude extract of S. racemosa. The standard drugs were also used for further screening of the fractions of S. racemosa. Hot plate, writhing test, formalin test and carrageenan-induced paw edema in mice and rats were performed for determination of analgesic and anti-inflammatory activities respectively on S. racemosa bark extract. The results exhibited significant anti-inflammatory and analgesic effect at 300 and 500mg/kg doses.

Anti-nociceptive activity of seed extract of Vernonia anthelmintica willd.

Vernonia anthelmintica is commonly known as kali ziri. Its seeds are used for several therapeutical purposes. Its seeds contain many constituents of medicinal importance as vernodlin, vernodalol, and vernolic acid. It is commonly used psoriasis and leucoderma or white leprosy. It is potent wormicidal agent. The present study was conducted on seed's extract of V. anthelmintica to determine its analgesic potency. The activity was conducted on mice by using acetic acid induced writhes,hot plate method and by tail flick method using water bath. The results of the writhing test were highly significant and comparable with Aspirin, which produced 26 and 20 writhes. The percentage of inhibition of writhes with the two doses of crude extract was 65.45% and 64.28% at 300mg/kg, while 83.63% and 71.42% at 500mg/kg, where as with Aspirin it was 52.72% and 28.57% in first and second phase respectively. Hot plate and tail flick method also indicated that vernonia has potent analgesic activity. The drug can be utilized as anti-nociceptive agent.

Assessment of anti-inflammatory, anti-ulcer and neuro-pharmacological activities of Cyperus rotundus Linn.

This article reports the assessment of anti-inflammatory, antiulcer and neuropharmacological activities of crude extract of Cyperus rotundus. The plant exhibited significant property to act as an anti inflammatory agent. In experimental design, inflammation was produced by carrageenan in rats and compare with saline treated and Aspirin treated group. Simultaneously the drug was also observed for its antiulcer response and found effective enough (these two activities were observed at the dosage of 300mg/kg and 500mg/kg). The anti ulcer activity was observed 41.2% as a dosage of 500mg/kg. Neuropharmacological activities (open field, head dip, rearing traction and forced swimming test) were also observed at 300 and 500mg/kg of C. rotundus extract. The crude extract showed mild decreased in all test and exhibited slight muscle relaxant effect. Powder drug studies and FTIR analysis were performed for the authentication of C. rotundus.

Hesitancy Towards COVID-19 Vaccine Among Students of Medical and Allied Health Sciences in Khyber Pakhtunkhwa.

Objective: To measure COVID-19 vaccine hesitancy and its associated factors among medical and allied health sciences students of Khyber Pakhtunkhwa. Methodology: This cross-sectional survey was conducted online using Google survey platform in March 2021. Study population comprised of medical and allied health sciences students studying in medical/allied health sciences academic institutes in Khyber Pakhtunkhwa. The web-based online link was provided to around 800 students to fill in the questionnaire via email, WhatsApp and/or social media network. Response rate was around 50%. The main outcome variable was vaccine hesitancy. Factors associated with vaccine hesitancy were explored by bivariate and multivariate regression analysis. Results: Out of 398 medical and allied health sciences students, there were 193 (48.5%) males and 205 (51.5%) females with mean age was 22.6± 2.8 years. The vaccine hesitancy rate was found to be 52.8%. A significant relationship between vaccine hesitancy and gender was observed. Other factors including lack of adequate knowledge about vaccines (p < 0.001), Chinese origin of vaccines (p < 0.001), lack of knowledge that vaccination can reduce the chances of acquiring infection (p < 0.001), fear of potential side effects (p < 0.001) and hidden agenda behind free forceful vaccination (p = 0.045), were found to be main barriers or reasons responsible for COVID-19 vaccine hesitancy among medical and allied health sciences students. Conclusion: Important associated barriers with COVID-19 vaccine hesitancy included gender, lack of information, fear of side effects, lack of trust in imported and Chinese vaccines, and perception of hidden agenda behind COVID-19 vaccination.

Immunohistochemical Expression of Epidermal Growth Factor Receptor (EGFR) in Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders.

BACKGROUND: Increased epidermal growth factor receptor (EGFR) expression has been implicated in several tumors and is associated with increased tumor advancement as well as a potential drug target. The objective of the study was to compare the immunohistochemical expression of EGFR in oral squamous cell carcinoma (OSCC) with oral potentially malignant disorders (OPMDs) and their demographic and pathologic parameters. METHODS: This study was a comparative cross-sectional analytical study. It was conducted at the Department of Pathology, Peshawar Medical College, Riphah International University, Islamabad, Pakistan, from March 2021 to February 2022. The sample size was calculated through G Power. Thirty-eight cases of oral squamous cell carcinoma and 38 cases of oral potentially malignant disorders (OPMDs) were included in the study. Statistical analysis was performed using the Statistical Package for Social Sciences version 20.0. χ 2 tests and Fisher exact tests were applied to compare categorical variables. RESULTS: Mean age of OSCC was 61.6±13.9, with age range from 26 to 90 years. The male-to-female ratio for OSCC was 2.16:1. Buccal mucosa was the most common site involved (34.2%). The most common histologic type was well-differentiated OSCC (71.05%) followed by poorly differentiated (16%) and moderately differentiated (13.15%). The mean age of OPMDs cases was 59.16 ± 10.81 with a male-to-female ratio of 1:1.2. Buccal mucosa was the common site (55.3%), followed by the tongue (18.4%). The OPMDs with dysplasia were 55.2%, and without dysplasia were 44.8%. A total of 55.7% of cases of OSCC showed positive EGFR expression as compared with 36.9% OPMDs cases. A higher number of low-grade OSCC cases showed increased EGFR positivity (59.3%) as compared with high grade (45.45%). EGFR positivity in OPMD cases without dysplasia was 41.2% as compared with cases with dysplasia (33.3%). The EGFR expression in OPMD cases was higher in the ≤50 age group ( P =0.001) and in females ( P =0.032), which was statistically significant. CONCLUSIONS: EGFR expression by Immunohistochemistry may not be a helpful prognostic marker to determine the risk of OPMDs progressing to higher grades of dysplasia or invasive cancer. However, further studies relating this tumor marker to stage, lymph node metastasis, hematogenous metastasis, survival outcomes, and treatment response may give useful information regarding the utility of this marker.

Covered stents in the management of native coarctation of the aorta--intermediate and long-term follow-up.

OBJECTIVES: To evaluate the results of covered Cheatham-Platinum stent implantation in the management of native coarctation of the aorta and report intermediate and long-term follow-up. BACKGROUND: Covered stents are being used increasingly in severe and complex coarctation of the aorta mainly to reduce risk of aortic wall complications. There is, however, limited data on the intermediate and long-term outcome. PATIENTS AND METHODS: Fifty-six patients received 59 covered Cheatham-Platinum stents (January 2002-December 2011) at a single center-in 54 patients as primary treatment and in 2 as a rescue. Mean age was 22.25 ± 1.2 (11-56) years and mean weight 58.6 ± 2.1 (32-99) kg. Primary end points were reduction in systolic pressure gradient and an increase in coarctation segment diameter. Changes in antihypertensive medicines and complications were recorded on follow-up. RESULTS: Mean coarctation segment diameter increased from 4.69 ± 0.20 to 15.1 ± 3.2 mm (P < 0.0001). The systolic gradient decreased from mean of 51.4 ± 3.4 to 4.6 ± 0.7 mm Hg (P < 0.0001). There was one death 3 days postprocedure due to cerebral anoxia. There was one dissection diagnosed 24-hr postprocedure. At a mean follow-up of 45.9 ± 3.9 (3-120) months, all stents were patent and in good position on computed tomography. Four (7.1%) patients underwent successful redilation. Antihypertensive medication was decreased or stopped in 37 (66%) patients. CONCLUSIONS: Covered Cheetham-Platinum stents may be used effectively as therapy of choice in selected patients with severe coarctation of the aorta. Aortic wall complications occur even with covered stents. Covered stents provide a safe alternative to conventional stenting in the intermediate and long-term and can be redilated safely to keep pace with somatic growth.

Anti-nucleocapsid IgG antibodies in SARS-CoV-2 recovered health care workers: One year follow-up study.

Objective: The objective of this study was to evaluate the magnitude and durability of the anti-nucleocapsid-IgG antibody titer in healthcare workers previously infected with SARS-CoV-2 for a period of 12 months.Methods: This study examined blood samples for SARS-CoV-2-specific IgG collected periodically from 120 healthcare workers previously infected with SARS-CoV-2 (confirmed by RT-PCR) and followed longitudinally up to 12 months from their enrolment into the study.Results: The median anti-N-IgG antibody level identified at 3 months was 23.7 CO-index (IQR: 9.13-50.27) and increased to 32.9 CO-index (IQR: 11.8-84.4) at 6 months. At 9 months, the median anti-N-IgG antibody level started to wane in the subsequent time and was dropped to 14 CO-index (IQR: 3.4-37.6) and declined further to 9.8 CO-index at 12 months (IQR: 2.8-9.8). When classified by age groups, the only statistically significant difference in anti-N-IgG between the two age groups (≤30 years and >30 years) was identified at 12 month time point (median difference 8.06, p = 0.035). Spearman correlation coefficient was negatively associated between anti-N-IgG and time interval (r = -0.255, p = 0.000) but was not statistically significant with age of a patient (p > 0.05).Conclusions: In conclusion, SARS-CoV-2 antibody levels started declining after 6 months but remained detectable in the majority of patients up to 12 months.

Gene expression and transcriptional regulation driven by transcription factors involved in congenital heart defects.

BACKGROUND: Congenital heart disease (CHD) is one of the most important birth defects caused by more than one mutated gene. Mutations in the genes could cause different types of congenital heart defects including atrial septal defect (ASD), tetralogy of Fallot (TOF), and ventricular septal defect (VSD). OBJECTIVES: Cardiac transcription factors are key players for heart development and are actively involved in controlling stress regulation of the heart. Transcription factors are sequence-specific DNA binding proteins that control the process of transcription and work in a synergistic manner. We aim to characterize core cardiac transcription factors including NKX2-5, TBX, SRF, GATA4, and MEF2, which encode homeobox and MADS domain and play a crucial role in heart development. METHODS: In this study, we have explored the important transcription factors involved in cardiac development and genes controlling the expression and regulation process by using the bioinformatics approach. RESULTS: We have predicted the orthologs and homologs based on their evolutionary history, conserved protein domains, functional sites, and 3D structures for better understanding and presentation of factors responsible for causing CHD. Results showed the importance of these transcription factors for normal heart functioning and development. CONCLUSION: Understanding the molecular pathways and genetic basis of CHD will help to open a new door for the treatment of patients with cardiac defects.

Corrigendum: Additive manufacturing of Al2O3 ceramics with MgO/SiC contents by laser powder bed fusion process.

[This corrects the article DOI: 10.3389/fchem.2023.1034473.].

Additive manufacturing of Al2O3 ceramics with MgO/SiC contents by laser powder bed fusion process.

Laser powder bed fusion is a laser-based additive manufacturing technique that uses a high-energy laser beam to interact directly with powder feedstock. LPBF of oxide ceramics is highly desirable for aerospace, biomedical and high-tech industries. However, the LPBF of ceramics remains a challenging area to address. In this work, a new slurry-based approach for LPBF of ceramic was studied, which has some significant advantages compared to indirect selective laser sintering of ceramic powders. LPBF of Al2O3 was fabricated at different MgO loads up to 80 wt%. Several specimens on different laser powers (70 W-120 W) were printed. The addition of magnesia influenced the microstructure of the alumina ceramic significantly. The findings show that when the laser power is high and the magnesia load is low, the surface quality of the printing parts improves. It is feasible to produce slurry ceramic parts without binders through LPBF. Furthermore, the effects of SiC and MgO loads on the microstructure and surface morphology of alumina are compared and analysed.

Comparison of Changes in Speciality Choices and Future Career Plans between Public and Private Medical Students Over Five Years of Medical Studies.

This study aimed to compare medical students' satisfaction with their choice of the medical field in their fifth year to their first year of MBBS and to compare speciality choices and career plans between public and private medical students. It was an online survey conducted from December 2020 to April 2021. Two consecutive classes of final-year medical students from five medical schools (2 public and 3 private) were included. They were asked about their satisfaction with the medical profession, intentions to practice abroad, intended speciality, and career plans in the final year and the first year of medical school via a 24-item semi-structured pre-piloted questionnaire. Of 468 responses (34.41% response rate), 331 (70.7%) were females. There was a significant change (p = 0.002) in the intention of students to practice abroad, however, no significant change (p=0.11) in their satisfaction with the medical profession was observed. Key Words: Career choices, Medical students, Medical schools, Personal satisfaction, Pakistan.

Correction: Vat photopolymerization-based 3D printing of polymer nanocomposites: current trends and applications.

[This corrects the article DOI: 10.1039/D2RA06522C.].

Incidence of SARS-CoV-2 re-infection in anti-nucleocapsid IgG-positive healthcare workers: a prospective cohort study.

BACKGROUND : Since the pandemic of SARS-CoV-2 began, our understanding of the pathogenesis and immune responses to this virus has continued to evolve. It has been shown that this infection produces natural detectable immune responses in many cases. However, the duration and durability of immunity and its effect on the severity of the illness are still under investigation. Moreover, the protective effects of antibodies against new SARS-CoV-2 variants still remain unclear. OBJECTIVES: To assess the incidence and associated demographic features of SARS-CoV-2 infection in anti-nucleocapsid IgG-positive and anti-nucleocapsid IgG-negative healthcare workers. MATERIAL AND METHODS: This prospective longitudinal cohort study was conducted in Peshawar Medical College group of hospitals of Prime Foundation. Anti-nucleocapsid IgG sero-positive and anti-nucleocapsid IgG sero-negative healthcare workers were followed for a period of 6 months (from 1 Aug 2020 to 31 Jan 2021), and the incidence of SARS-CoV-2 was confirmed by RT-PCR. RESULTS: A total number of 555 cohorts were followed for a period of 6 months; of them 365 (65.7%) were anti-nucleocapsid-negative (group A) and 190 (34.3%) were anti-nucleocapsid-positive (group B) healthcare workers. The mean age of the study cohort was 33.85 ± 9.80 (anti-N (-), 34.2 ± 10.58; anti-N ( +), 33.5 ± 9.50). The median antibody level in anti-nucleocapsid-positive HCWs was 15.95 (IQR: 5.24-53.4). Male gender was the majority in both groups (group A, 246 (67%), group B, 143 (48%)) with statistically significant difference (P < 0.05). Majority of the HCWs were blood group B in both groups (34% each). None of the 190 anti-nucleocapsid-positive HCWs developed subsequent SARS-CoV-2 re-infection, while 17% (n = 65) HCWs developed infection in anti-nucleocapsid-negative group during the 6-month follow-up period. CONCLUSION: In conclusion, none of the anti-nucleocapsid-positive HCWs developed SARS-CoV-2 re-infection in this study, and the presence of IgG anti-nucleocapsid antibodies substantially reduce the risk of re-infection for a period of 6 months.