Antibody Response after Homologous and Heterologous Prime-Boost COVID-19 Vaccination in a Bangladeshi Residential University Cohort.

COVID-19 vaccination strategies, including heterologous prime-boost regimens and additional booster doses, aim to optimize immune responses. However, seroepidemiological studies on immune responses to different COVID-19 vaccine types and schedules remain limited. This study investigated antibody levels following homologous and heterologous prime-and-boost COVID-19 vaccination in Bangladesh. In a cohort of 606 participants who received first/second/booster doses of vaccines (AstraZeneca, Moderna, Pfizer-BioNTech, and Sinopharm), anti-spike IgG and anti-nucleocapsid IgG levels were measured. Antibody titer variations with respect to age, gender, intervals between doses, and prior infection status were analyzed. mRNA vaccines elicited the highest antibody levels after homologous and heterologous boosting. The AstraZeneca booster resulted in a sharp titer decline rate of ~0.04 units per day. Second or booster vaccine doses significantly increased antibody levels, especially in males (p < 0.05). Older age correlated with higher titers, likely reflecting previous infection, which was further confirmed by the elevation of anti-nucleocapsid IgG levels. About 95.5% of non-Sinopharm recipients were anti-nucleocapsid IgG positive, suggesting prior exposure exceeding self-reported infections (12.5%). mRNA and heterologous COVID-19 boosting enhances humoral immunity over homologous prime-boost vector/inactivated vaccination. However, waning immunity merits further investigation across vaccine platforms.

The Disruptive Impact of COVID-19 on the Utilization of Cancer Chemotherapy-Related Healthcare Assistance at the Principal Nationwide Referral Hospital in Kenya.

Background Lockdown measures to reduce the outbreak of COVID-19 negatively impacted the administration of cancer chemotherapy globally; however, data from Kenya are limited. Researchers strove to address this information gap and assess chemotherapy trends before and during the pandemic at Kenyatta National Hospital (KNH), the most wide-ranging referral infirmary in Kenya, along with associated factors to provide future guidance. Methods Time series analyses and patient interviews were undertaken at the KNH Cancer Treatment Centre. Patient data were analyzed descriptively and inferentially. The average quarterly scores of chemotherapy-related patients from January 2019 to December 2020 were computed for the time series analysis. Results A total of 241 participants were recruited. Of the participants, 164 (68%) were female, and the mean age was 55. Breast cancer was the most typical cancer type. Independent risk factors for missed chemotherapy sessions were a considerable increase in travel costs, rescheduled appointments alongside difficulties in securing an appointment, comorbidities, and marital status. There was a decline in chemotherapy utilization before COVID-19, with a sharp drop at the pandemic's peak. Conclusion COVID-19 and associated measures did appreciably affect the treatment of cancer patients with chemotherapy in this developing country, with several factors contributing to this. Efforts should be geared toward continuity of services during future pandemics in developing countries to improve patient outcomes.

Optimizing SARS-CoV-2 Immunoassays for Specificity in Dengue-Co-Endemic Areas.

Introduction The overlap in clinical presentation between COVID-19 and dengue poses challenges for diagnosis in co-endemic regions. Furthermore, there have been reports of antibody cross-reactivity between SARS-CoV-2 and dengue. Our research aims to evaluate SARS-CoV-2 antigens for serological testing while reducing the possibility of cross-reactivity with anti-dengue antibodies. Method Two hundred and ten serum samples were collected from 179 patients and divided into four panels. Panels 1 and 2 consisted of COVID-19-negative healthy donors (n=81) and pre-pandemic dengue patients (n=50), respectively. Alternatively, Panel 3 (n=19) was composed of reverse transcription-quantitative polymerase chain reaction (RT-qPCR)-positive samples collected within two weeks of COVID-19 symptom onset, while Panel 4 (n=60) was composed of positive samples collected after two weeks of symptom onset. Previously developed and characterized in-house SARS-CoV-2 spike-1 (S1), receptor binding domain (RBD), and nucleocapsid (N) immunoglobin G (IgG)-enzyme-linked immunosorbent assay (ELISA) assays were used for the study. Results Six dengue-positive sera cross-reacted with the RBD of SARS-CoV-2. However, only one dengue-positive sera cross-reacted with the S1 and N proteins of SARS-CoV-2. Co-immobilization of S1 and RBD in different ratios revealed an 80:20 (S1:RBD) ratio as optimal for achieving an overall 96.2% sensitivity with the least cross-reaction to anti-dengue antibodies. Conclusion Our findings indicated that SARS-CoV-2 RBD-based immunoassays present more cross-reactivity with anti-dengue antibodies than S1 and N proteins. Furthermore, co-immobilization of S1 and RBD reduces the cross-reactivity with anti-dengue antibodies compared to RBD, thereby increasing the immunoassay specificity without affecting overall sensitivity for the dengue-endemic areas.

Phylogenetic diversity and functional potential of the microbial communities along the Bay of Bengal coast.

The Bay of Bengal, the world's largest bay, is bordered by populous countries and rich in resources like fisheries, oil, gas, and minerals, while also hosting diverse marine ecosystems such as coral reefs, mangroves, and seagrass beds; regrettably, its microbial diversity and ecological significance have received limited research attention. Here, we present amplicon (16S and 18S) profiling and shotgun metagenomics data regarding microbial communities from BoB's eastern coast, viz., Saint Martin and Cox's Bazar, Bangladesh. From the 16S barcoding data, Proteobacteria appeared to be the dominant phylum in both locations, with Alteromonas, Methylophaga, Anaerospora, Marivita, and Vibrio dominating in Cox's Bazar and Pseudoalteromonas, Nautella, Marinomonas, Vibrio, and Alteromonas dominating the Saint Martin site. From the 18S barcoding data, Ochrophyta, Chlorophyta, and Protalveolata appeared among the most abundant eukaryotic divisions in both locations, with significantly higher abundance of Choanoflagellida, Florideophycidae, and Dinoflagellata in Cox's Bazar. The shotgun sequencing data reveals that in both locations, Alteromonas is the most prevalent bacterial genus, closely paralleling the dominance observed in the metabarcoding data, with Methylophaga in Cox's Bazar and Vibrio in Saint Martin. Functional annotations revealed that the microbial communities in these samples harbor genes for biofilm formation, quorum sensing, xenobiotics degradation, antimicrobial resistance, and a variety of other processes. Together, these results provide the first molecular insight into the functional and phylogenetic diversity of microbes along the BoB coast of Bangladesh. This baseline understanding of microbial community structure and functional potential will be critical for assessing impacts of climate change, pollution, and other anthropogenic disturbances on this ecologically and economically vital bay.

Electrolyte Imbalance Among Bangladeshi Patients With COVID-19.

Introduction Infection with SARS-CoV-2 begins in the lower respiratory tract, but COVID-19 often involves the renal system, resulting in serum electrolyte imbalance. Monitoring serum electrolyte levels and parameters of liver and kidney function is essential to understand disease prognosis. Objectives This study aimed to determine the effect of imbalances in serum electrolytes and other parameters on COVID-19 severity. Material and method This retrospective study comprised 241 patients, ages 14 years and older, including 186 patients who were moderately affected and 55 who were categorized as severely affected by COVID-19. Serum electrolytes (sodium (Na+), potassium (K+), and chloride (Cl-)) and biomarkers of kidney and liver function (creatinine and alanine aminotransferase (ALT)) were measured and correlated with disease severity. This research was conducted among admitted patients of Holy Family Red Crescent Medical College Hospital designated into two groups based on retrospective hospital records. Individuals with moderate illness had evidence of lower respiratory tract infection (cough, cold, breathless, etc.) during clinical assessment or imaging (chest X-ray and computed tomography (CT) scan of the lungs) and have an oxygen saturation by pulse oximetry (SpO2) ≥ 94% on room air at sea level. The severely ill group involved individuals with SpO2 ≤94% on room air at sea level and respiratory rate ≥ 30 breaths/minute, and critically ill patients are those who needed mechanical ventilation or required intensive care unit (ICU) care. This categorization was based on the Coronavirus Disease 2019 (COVID-19) Treatment Guidelines (https://www.covid19treatmentguidelines.nih.gov/about-the-guidelines/whats-new/). Results Average Na+ and creatinine increased by 2.30 parts (95% confidence interval (CI) = 0.20, 4.81, P = 0.041) and 0.35 units (95% CI = 0.03, 0.68, P = 0.043) in severe cases compared with moderate cases. Older participants had relatively Na+ lowered to -0.06 parts (95% CI = -0.12, -0.001, P = 0.045), significant Cl- reduction by 0.09 units (95% CI = -0.14, -0.04, P = 0.001), and ALT by 0.47 units (95% CI = -0.88, -0.06, P = 0.024), whereas serum creatinine was increased by 0.01 parts (95% CI = 0.001, 0.02, P = 0.024). The creatinine and ALT of COVID-19 participants were significantly higher in males by 0.34 units and 23.2 units, respectively, compared with females. In severe COVID-19 cases compared with moderate cases, the risks of hypernatremia, elevated chloride levels, and elevated serum creatinine levels were increased by 2.83-fold (95% CI = 1.26, 6.36, P = 0.012), 5.37-fold (95% CI = 1.90, 15.3, P = 0.002), and 2.00-fold (95% CI = 1.08, 4.31, P = 0.039), respectively. Conclusion Serum electrolyte and biomarker levels can serve as good indicators of the condition and disease prognosis of patients with COVID-19. Our purpose in this study was to determine the association between serum electrolyte imbalance and disease severity. We collected data from ex post facto hospital records and did not intend to assess the mortality rate. Consequently, this study expects that the prompt diagnosis of electrolyte disparity or disturbance possibly minimizes COVID-19-related morbidity and mortality.

Breast Cancer Management in the Era of Covid-19; Key Issues, Contemporary Strategies, and Future Implications.

During the COVID-19 pandemic, several priority diseases were not getting sufficient attention. Whilst breast cancer is a fatal disease affecting millions worldwide, identification and management of these patients did not initially attract critical attention to minimize the impact of lockdown, post-lockdown, and other measures. Breast cancer patients' conditions may not remain stable without proper care, worsening their prognosis. Proper care includes the timely instigation of surgery, systemic therapy, and psychological support. This includes low-and middle-income countries where there are already concerns with available personnel and medicines to adequately identify and treat these patients. Consequently, there was a need to summarize the current scenario regarding managing breast cancer care during COVID-19 across all countries, including any guidelines developed. We systematically searched three scientific databases and found 76 eligible articles covering the medical strategies of high-income countries versus LMICs. Typically, diagnostic facilities in hospitals were affected at the beginning of the pandemic following the lockdown and other measures. This resulted in more advanced-stage cancers being detected at initial presentation across countries, negatively impacting patient outcomes. Other than increased telemedicine, instigating neo-adjuvant endocrine therapy more often, reducing non-essential visits, and increasing the application of neo-adjuvant chemotherapy to meet the challenges, encouragingly, there was no other significant difference among patients in high-income versus LMICs. Numerous guidelines regarding patient management evolved during the pandemic to address the challenges posed by lockdowns and other measures, which were subsequently adopted by various high-income countries and LMICs to improve patient care. The psychological impact of COVID-19 and associated lockdown measures, especially during the peak of COVID-19 waves, and the subsequent effect on the patient's mental health must also be considered in this high-priority group. We will continue to monitor the situation to provide direction in future pandemics.

Classic and Current Opinions in Human Organ and Tissue Transplantation.

Graft tolerance is a pathophysiological condition heavily reliant on the dynamic interaction of the innate and adaptive immune systems. Genetic polymorphism determines immune responses to tissue/organ transplantation, and intricate humoral and cell-mediated mechanisms control these responses. In transplantation, the clinician's goal is to achieve a delicate equilibrium between the allogeneic immune response, undesired effects of the immunosuppressive drugs, and the existing morbidities that are potentially life-threatening. Transplant immunopathology involves sensitization, effector, and apoptosis phases which recruit and engages immunological cells like natural killer cells, lymphocytes, neutrophils, and monocytes. Similarly, these cells are involved in the transfer of normal or genetically engineered T cells. Advances in tissue transplantation would involve a profound knowledge of the molecular mechanisms that underpin the respective immunopathology involved and the design of precision medicines that are safe and effective.

Antimicrobial Prescribing Confidence and Knowledge Regarding Drug Resistance: Perception of Medical Students in Malaysia and the Implications.

BACKGROUND: Worldwide, microbes are becoming more challenging by acquiring virulent skills to adapt and develop antimicrobial resistance (AMR). This is a concern as AMR increases morbidity, mortality, and costs. Consequently, physicians need to be trained on appropriate antimicrobial prescribing, starting as medical students. OBJECTIVE: To evaluate medical students' confidence in antimicrobial prescribing and AMR. METHODS: Cross-sectional study assessing medical students' knowledge, perception, and confidence in prescribing antimicrobials and AMR in a Malaysian University. A universal sampling method was used. RESULTS: Most responding students believed that educational input regarding overall prescribing was sufficient. Regarding the principle of appropriate and accurate prescriptions, female medical students had less knowledge (odds ratio (OR) = 0.51; 95% confidence interval (CI) 0.25-0.99; p = 0.050). Year-IV and Year-V medical students had more excellent knowledge than Year-III students regarding confidence in potential antibiotic prescribing once qualified. Year-V students also showed an appreciably higher confidence in the broad principles of prescribing, including antibiotics for infectious diseases, compared to those in other years. CONCLUSION: Overall, medical students gain more knowledge and confidence regarding the potential prescribing of antimicrobials as their academic careers progress. This is important given concerns with the current excessive use of antimicrobials in Malaysia.

Microfluidics Technology in SARS-CoV-2 Diagnosis and Beyond: A Systematic Review.

With the progression of the COVID-19 pandemic, new technologies are being implemented for more rapid, scalable, and sensitive diagnostics. The implementation of microfluidic techniques and their amalgamation with different detection techniques has led to innovative diagnostics kits to detect SARS-CoV-2 antibodies, antigens, and nucleic acids. In this review, we explore the different microfluidic-based diagnostics kits and how their amalgamation with the various detection techniques has spearheaded their availability throughout the world. Three other online databases, PubMed, ScienceDirect, and Google Scholar, were referred for articles. One thousand one hundred sixty-four articles were determined with the search algorithm of microfluidics followed by diagnostics and SARS-CoV-2. We found that most of the materials used to produce microfluidics devices were the polymer materials such as PDMS, PMMA, and others. Centrifugal force is the most commonly used fluid manipulation technique, followed by electrochemical pumping, capillary action, and isotachophoresis. The implementation of the detection technique varied. In the case of antibody detection, spectrometer-based detection was most common, followed by fluorescence-based as well as colorimetry-based. In contrast, antigen detection implemented electrochemical-based detection followed by fluorescence-based detection, and spectrometer-based detection were most common. Finally, nucleic acid detection exclusively implements fluorescence-based detection with a few colorimetry-based detections. It has been further observed that the sensitivity and specificity of most devices varied with implementing the detection-based technique alongside the fluid manipulation technique. Most microfluidics devices are simple and incorporate the detection-based system within the device. This simplifies the deployment of such devices in a wide range of environments. They can play a significant role in increasing the rate of infection detection and facilitating better health services.

The Effect of Socio-Demographic Factors in Health-Seeking Behaviors among Bangladeshi Residents during the First Wave of COVID-19.

Background: Socio-demographic variability among nations and cultures highly influences health-seeking behavior (HSB) in managing endemic or pandemic diseases. The present study aimed to investigate the influence of socio-demographic factors on HSB among Bangladeshi residents during the first wave of COVID-19. Methods: A cross-sectional online survey was performed with Bangladeshi residents (60% male and 40% female; age range: 10−60 years or above) from May to July 2020. Information was collected from the participants who resided in slum areas or did not have internet access through face-to-face surveys, maintaining spatial distancing and proper preventive measures. A self-reported and structured questionnaire, including socio-demographic and HSB, was undertaken, and the data was analyzed using a convenience sampling method. Finally, among the 947 participants, 20 were selected using a stratified random sampling technique for in-depth-interview (IDI). The linear regression analysis was performed to determine the influence of socio-demographic factors on HSB. Results: Only about 4.2% of respondents did not wear masks, but nearly half of the participants (46.6%) did not use hand gloves. The mean score of HSB was 9.98 (SD = 2.01) out of 16, with a correct overall rate of 62.4%. As per regression analysis, higher HSBs were found among participants who reported older age (>50 years) (9.96 ± 2.45), educated unemployed students (10.1 ± 1.95), higher education (10.5 ± 1.76), and higher-income (10.4 ± 1.59); in contrast, participants living in slum areas (8.18 ± 2.34) and whose source of income was business (8.46 ± 2.04) exhibited lower HSBs. Females, compared to men, showed better HSB in every aspect, apart from online food ordering. Qualitative data showed that the younger generation is more aware because of their access to information and persuaded the older generations to follow health-seeking protocols. The results also showed that some lower-income slum-dwellers have access to information and healthcare through their employers. IDIs also found cultural, religious, and mental-health affect people's adherence to health-seeking guidelines and regulations. Conclusions: The findings suggest that socio-demographic factors significantly influenced HSBs during COVID-19 in the Bangladeshi population. Authorities can use these observations to systematically manage future endemics or pandemics.

Management of Children Admitted to Hospitals across Bangladesh with Suspected or Confirmed COVID-19 and the Implications for the Future: A Nationwide Cross-Sectional Study.

There is an increasing focus on researching children admitted to hospital with new variants of COVID-19, combined with concerns with hyperinflammatory syndromes and the overuse of antimicrobials. Paediatric guidelines have been produced in Bangladesh to improve their care. Consequently, the objective is to document the management of children with COVID-19 among 24 hospitals in Bangladesh. Key outcome measures included the percentage prescribed different antimicrobials, adherence to paediatric guidelines and mortality rates using purposely developed report forms. The majority of 146 admitted children were aged 5 years or under (62.3%) and were boys (58.9%). Reasons for admission included fever, respiratory distress and coughing; 86.3% were prescribed antibiotics, typically parenterally, on the WHO 'Watch' list, and empirically (98.4%). There were no differences in antibiotic use whether hospitals followed paediatric guidance or not. There was no prescribing of antimalarials and limited prescribing of antivirals (5.5% of children) and antiparasitic medicines (0.7%). The majority of children (92.5%) made a full recovery. It was encouraging to see the low hospitalisation rates and limited use of antimalarials, antivirals and antiparasitic medicines. However, the high empiric use of antibiotics, alongside limited switching to oral formulations, is a concern that can be addressed by instigating the appropriate programmes.

Detection of SARS-CoV-2 by antigen ELISA test is highly swayed by viral load and sample storage condition.

BACKGROUND: Rapid increase in COVID-19 suspected cases has rendered disease diagnosis challenging, mainly depending upon RT-qPCR. Reliable, rapid, and cost-effective diagnostic assays that complement RT-qPCR should be introduced after thoroughly evaluating their performance upon various disease phases, viral load, and sample storage conditions. OBJECTIVE: We investigated the correlation of cycle threshold (Ct) value, which implies the viral load and infection phase, and the storage condition of the clinical specimen with the diagnosis of SARS-CoV-2 through our newly developed in-house rapid enzyme-linked immunosorbent assay (ELISA) system. METHOD: Naso-oropharyngeal samples of 339 COVID-19 suspected cases were collected and evaluated through RT-qPCR that were stored up to 30 days in different conditions (i.e. -80°C, -20°C and initially at 4°C followed by -80°C). The clinical specimens were evaluated with our in-house ELISA system after finalizing the assay method through checkerboard assay and minimizing the signal/noise ratio. RESULT: The ELISA system showed the highest sensitivity (92.9%) for samples with Ct ≤30 and preserving at -80°C temperature. The sensitivity reduced proportionally with increasing Ct value and preserving temperature. However, the specificity ranged between 98.3% and 100%. CONCLUSION: The results indicate the necessity of early infection phase diagnosis and lower temperature preservation of samples to perform rapid antigen ELISA tests.

Application of Rapid Biological Indicators Coupled With Auto-Reader for the Quality Assurance of Surgical Instruments After Sterilization at a Cardiac Hospital in Bangladesh.

Background Sterilization failure is one of the main reasons for surgical site infections (SSIs). The biological indicator (BI) test is the most reliable test to check sterilization efficiencies. But 48 hours BI test result makes the monitoring process time-consuming. Rapid BI testing can be time demanding in this regard. Therefore, the objective is to determine the importance of rapid BI monitoring for the quality assurance of sterile surgical instruments. Methods This study was conducted in the Labaid Cardiac Hospital, Bangladesh from April 1, 2021, to July 8, 2021. A total of 100 steam and 100 ethylene oxide (EO) rapid BIs and an auto reader incubator were used to conduct this research. Quick BI of steam and EO were used once per day and tested by the auto reader. Later, all the tested BIs were incubated for 48 hours by a conventional incubator to confirm the auto reader's rapid BI test results. Result All the EO BI results were found negative, but the BI was found positive twice in steam sterilization. Surgical items of those two loads were re-sterilized. Again, after checking the BI result, the items were released. All BIs except positive steam rapid BIs were found with no growth after 48 hours of incubation for cross-checking of auto reader results. In positive rapid BI of steam, growth was found after 48 hours of incubation. Conclusion When sterilization failure occurred, process recall could not be possible at that time if rapid BI tests were not performed. So, integration of a rapid BI test with an auto reader can save the patient from critical SSI.

A Systematic Review on COVID-19 Vaccine Strategies, Their Effectiveness, and Issues.

COVID-19 vaccines are indispensable, with the number of cases and mortality still rising, and currently no medicines are routinely available for reducing morbidity and mortality, apart from dexamethasone, although others are being trialed and launched. To date, only a limited number of vaccines have been given emergency use authorization by the US Food and Drug Administration and the European Medicines Agency. There is a need to systematically review the existing vaccine candidates and investigate their safety, efficacy, immunogenicity, unwanted events, and limitations. The review was undertaken by searching online databases, i.e., Google Scholar, PubMed, and ScienceDirect, with finally 59 studies selected. Our findings showed several types of vaccine candidates with different strategies against SARS-CoV-2, including inactivated, mRNA-based, recombinant, and nanoparticle-based vaccines, are being developed and launched. We have compared these vaccines in terms of their efficacy, side effects, and seroconversion based on data reported in the literature. We found mRNA vaccines appeared to have better efficacy, and inactivated ones had fewer side effects and similar seroconversion in all types of vaccines. Overall, global variant surveillance and systematic tweaking of vaccines, coupled with the evaluation and administering vaccines with the same or different technology in successive doses along with homologous and heterologous prime-booster strategy, have become essential to impede the pandemic. Their effectiveness appreciably outweighs any concerns with any adverse events.

Antibody response to the first dose of AZD1222 vaccine in COVID-19 convalescent and uninfected individuals in Bangladesh.

BACKGROUND: Vaccination with the Oxford-AstraZeneca COVID-19 vaccine (AZD1222) initially started in the UK and quickly implemented around the Globe, including Bangladesh. Up to date, more than nine million doses administrated to the Bangladeshi public. METHOD: Herein, we studied the antibody response to the first dose of AZD1222 in 86 Bangladeshi individuals using in-house ELISA kits. Study subjects were categorized into two groups, convalescent and uninfected, based on prior infection history and SARS-CoV-2 nucleocapsid-IgG profiles. RESULTS: All the convalescent individuals presented elevated spike-1-IgG compared to 90% of uninfected ones after the first dose. Day >28 post-vaccination, the convalescent group showed six times higher antibody titer than the uninfected ones. The most elevated antibody titers for the former and later group were found at Day 14 and Days >28 post-vaccination, respectively. The spike-1-IgA titer showed a similar pattern as spike-1-IgG, although in a low-titer. In contrast, the IgM titer did not show any significant change in either group. CONCLUSION: High antibody titer in the convalescent group, signify the importance of the first dose among the uninfected group. This study advocates the integration of antibody tests in vaccination programs in the healthcare system for maximizing benefit.

Genome Sequences of Two Novel Coronavirus (SARS-CoV-2) Isolates from Dhaka, Bangladesh.

This study reports the genome sequences of two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains detected in the nasopharyngeal swab specimens of two coronavirus disease 2019 (COVID-19) patients from Dhaka, Bangladesh.

Disproportionate COVID-19 vaccine acceptance rate among healthcare professionals on the eve of nationwide vaccine distribution in Bangladesh.

BACKGROUND: Acceptance of the COVID-19 vaccine by the target groups would play a crucial role in stemming the pandemic. Healthcare professionals (HCPs) are the priority group for vaccination due to them having the highest risk of exposure to infection. This survey aimed to assess their acceptance of COVID-19 vaccines in Bangladesh. RESEARCH DESIGN AND METHODS: A cross-sectional survey using an online questionnaire was conducted between January 3 to 25, 2021, among HCPs (n = 834) in Bangladesh. RESULTS: Less than 50% of HCPs would receive the vaccine against COVID-19 if available and 54% were willing to take the vaccine at some stage in the future. Female participants (OR:1.64;95%CI:1.172-2.297), respondents between 18-34 years old (OR:2.42; 95% CI:1.314-4.463), HCPs in the public sector (OR:2.09; 95% CI:1.521-2.878), and those who did not receive a flu vaccine in the previous year (OR:3.1; 95% CI:1.552-6.001) were more likely to delay vaccination. CONCLUSIONS: The study revealed that, if available, less than half of the HCPs would accept a COVID-19 vaccine in Bangladesh. To ensure the broader success of the vaccination drive, tailored strategies and vaccine promotion campaigns targeting HCPs and the general population are needed.

AuNP Coupled Rapid Flow-Through Dot-Blot Immuno-Assay for Enhanced Detection of SARS-CoV-2 Specific Nucleocapsid and Receptor Binding Domain IgG.

BACKGROUND: Serological tests detecting severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are widely used in seroprevalence studies and evaluating the efficacy of the vaccination program. Some of the widely used serological testing techniques are enzyme-linked immune-sorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and lateral flow immunoassay (LFIA). However, these tests are plagued with low sensitivity or specificity, time-consuming, labor-intensive, and expensive. We developed a serological test implementing flow-through dot-blot assay (FT-DBA) for SARS-CoV-2 specific IgG detection, which provides enhanced sensitivity and specificity while being quick to perform and easy to use. METHODS: SARS-CoV-2 antigens were immobilized on nitrocellulose membrane to capture human IgG, which was then detected with anti-human IgG conjugated gold nanoparticle (hIgG-AuNP). A total of 181 samples were analyzed in-house. Within which 35 were further evaluated in US FDA-approved CLIA Elecsys SARS-CoV-2 assay. The positive panel consisted of RT-qPCR positive samples from patients with both <14 days and >14 days from the onset of clinical symptoms. The negative panel contained samples collected from the pre-pandemic era dengue patients and healthy donors during the pandemic. Moreover, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FT-DBA were evaluated against RT-qPCR positive sera. However, the overall efficacies were assessed with sera that seroconverted against either nucleocapsid (NCP) or receptor-binding domain (RBD). RESULTS: In-house ELISA selected a total of 81 true seropositive and 100 seronegative samples. The sensitivity of samples with <14 days using FT-DBA was 94.7%, increasing to 100% for samples >14 days. The overall detection sensitivity and specificity were 98.8% and 98%, respectively, whereas the overall PPV and NPV were 99.6% and 99%. Moreover, comparative analysis between in-house ELISA assays and FT-DBA revealed clinical agreement of Cohen's Kappa value of 0.944. The FT-DBA showed sensitivity and specificity of 100% when compared with commercial CLIA kits. CONCLUSION: The assay can confirm past SARS-CoV-2 infection with high accuracy within 2 minutes compared to commercial CLIA or in-house ELISA. It can help track SARS-CoV-2 disease progression, population screening, and vaccination response. The ease of use of the assay without requiring any instruments while being semi-quantitative provides the avenue of its implementation in remote areas around the globe, where conventional serodiagnosis is not feasible.

Longitudinal Antibody Dynamics Against Structural Proteins of SARS-CoV-2 in Three COVID-19 Patients Shows Concurrent Development of IgA, IgM, and IgG.

BACKGROUND: Dynamics and persistence of neutralizing and non-neutralizing antibodies can give us the knowledge required for serodiagnosis, disease management, and successful vaccine design and development. The disappearance of antibodies, absence of humoral immunity activation, and sporadic reinfection cases emphasize the importance of longitudinal antibody dynamics against variable structural antigens. METHODS: In this study, twenty-five healthy subjects working in a SARS-COV-2 serodiagnostic assay development project were enrolled, and their sign and symptoms were followed up to six months. Three subjects showed COVID-19-like symptoms, and three subjects' antibody dynamics were followed over 120 days by analyzing 516 samples. We have developed 12 different types of in-house ELISAs to observe the kinetics of IgG, IgM, and IgA against four SARS-CoV-2 proteins, namely nucleocapsid, RBD, S1, and whole spike (S1+S2). For the development of these assays, 30-104 pre-pandemic samples were taken as negative controls and 83 RT-qPCR positive samples as positive ones. RESULTS: All three subjects presented COVID-19-like symptoms twice, with mild symptoms in the first episode were severe in the second, and RT-qPCR confirmed the latter. The initial episode did not culminate with any significant antibody development, while a multifold increase in IgG antibodies characterized the second episode. Interestingly, IgG antibody development concurrent with IgM and IgA and persisted, whereas the latter two weans off rather quickly if appeared. CONCLUSION: Antibody kinetics observed in this study can provide a pathway to the successful development of sero-diagnostics and epidemiologists to predict the fate of vaccination currently in place.