Accuracy of Anti-SARS-CoV-2 Antibody in Comparison with Surrogate Viral Neutralization Test in Persons Living with HIV, Systemic Lupus Erythematosus, and Chronic Kidney Disease.

The presence of the anti-SARS-CoV-2-RBD antibody (anti-RBD) prevents severe COVID-19. We aimed to determine the accuracy of a point-of-care anti-RBD testing implemented in persons living with HIV (PLWH), systemic lupus erythematosus (SLE), and chronic kidney disease (CKD). We enrolled 182 non-comorbid subjects and 335 comorbid subjects (PLWH, SLE, CKD) to test the anti-RBD assay compared to the surrogate viral neutralization test (sVNT) as the reference test. We performed linear correlation analysis between anti-RBD and sVNT, along with an ROC analysis to ascertain the anti-RBD cutoff at 30%, 60%, and 90% inhibition of sVNT, to calculate accuracy. The correlations between anti-RBD and sVNT among all groups were excellent, with R = 0.7903, R = 0.7843, and R = 0.8153 among the non-comorbid, SLE, and CKD groups, respectively, and with significantly higher correlation among the PLWH group (R = 0.8877; p-value = 0.0072) compared to the non-comorbid group. The accuracy of the anti-RBD test among the PLWH and CKD groups was similar to that among the non-comorbid group but showed lower sensitivity in the SLE group (p = 0.000014). The specificity of the test remained high in all groups. In conclusion, the anti-RBD test had excellent correlation with the sVNT. The persistently high specificity in all groups suggests that this test can be reliably utilized to detect the presence of low neutralization capacity, prompting additional vaccination.

High Levels of Anti-SARS-CoV-2 Receptor-Binding Domain (RBD) Antibodies One Year Post Booster Vaccinations among Hospital Workers in Indonesia: Was the Second Booster Needed?

In August 2022, Indonesia prioritized healthcare workers to receive the second booster dose. We conducted a sequential serosurvey to understand the dynamics of the antibody titers. The first serosurvey, which was conducted in June 2021, 1-6 months after Sinovac vaccination, showed a median antibody level of 41.4 BAU/mL (interquartile range (IQR): 10-629.4 BAU/mL). The second serosurvey was conducted one month (August 2021) after the first Moderna booster vaccine and showed a median level of 4000 BAU/mL (IQR: 3081-4000 BAU/mL). The last serosurvey was conducted a year (August 2022) after the booster and showed a median level of 4000 BAU/mL (IQR: 4000-4000 BAU/mL). In this last survey, only 39 (11.9%) of healthcare workers had antibody levels below the maximum level of 4000 BAU/mL. Thus, one year after the first booster dose, we did not observe the waning of antibody levels. The average increase was perhaps because of natural infection. Based on these considerations, we believe that a second booster dose was not necessary for this category of subjects at that time. Because vaccine supply is often limited, priority could be given to the general population or other high-risk patient groups with low antibody titers based on serological tests.

Anti-SARS-CoV-2 Antibody Level Is Associated with a History of COVID-19 Infection and mRNA Vaccination in Patients with Diabetes.

Type 2 diabetes mellitus (T2DM) is associated with higher severity and mortality in SARS-CoV-2 infections. Vaccination has been encouraged to boost immunity and prevent these unfortunate outcomes. Few studies have evaluated antibody levels after COVID-19 vaccination in patients with T2DM. Therefore, we examined the vaccination status and anti-SARS-CoV-2 antibody levels to identify the factors that affect the antibody levels in patients with T2DM. This cross-sectional study was conducted at the Dr. Hasan Sadikin Hospital and Bandung Kiwari Hospital, Bandung, West Java, Indonesia, between October and November 2022. Adult participants with and without T2DM were tested for SARS-CoV-2 antibodies using a point-of-care quantitative immunochromatographic assay. We enrolled 289 participants: 201 participants with T2DM and 88 participants without T2DM. The T2DM participants had a lower vaccination rate compared with the non-T2DM participants. However, no significant differences in antibody levels were observed between the two groups. Higher antibody levels among the T2DM participants were associated with mRNA vaccination and a history of COVID-19 illness. The lower antibody response observed among the T2DM participants with chronic obstructive pulmonary disease suggests that such patients may need antibody level measurement and an additional booster vaccine.

Dengue incidence and length of viremia by RT-PCR in a prospective observational community contact cluster study from 2005-2009 in Indonesia.

BACKGROUND: Dengue has become a major global health threat since being recognized three centuries ago. Important gaps remain in understanding the transmission dynamics of dengue virus (DENV) infection. This study reports the results of a prospective observational cluster study that investigated the incidence of symptomatic and asymptomatic infections and length of viremia among close community contacts of hospitalized DENV-infected patients. METHODOLOGY/PRINCIPAL FINDINGS: Between 2005 and 2009, dengue-confirmed cases (n = 97) admitted to Hasan Sadikin Hospital in Bandung, Indonesia, were enrolled as index cases. Subsequently, twenty close community contacts (n = 1928) living with and around the index cases were included and followed up for up to 14 days. Body temperature was measured daily; blood samples were collected every 3-4 days and when reported fever. DENV infection was confirmed using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR), IgM rapid test, and Enzyme-linked Immunosorbent Assay (ELISA). Among the 1928 community contacts, a total of 72 (3.7%) acute DENV infections were diagnosed, which equates to an incidence of 636 cases per 1,000 person-years (95% Confidence interval (CI) 588 to 687 cases per 1,000 person-years). Twenty-nine cases (40%) were symptomatic (22 dengue fever (DF) & 7 dengue hemorrhagic fever (DHF)), and 43 (60%) were asymptomatic. Primary and secondary DENV infections were detected in 18 (25%) and 54 (75%) subjects. Among the RT-PCR positives, viremia was observed as early as seven days before fever onset and converted to negative as late as seven days after the onset of fever. CONCLUSIONS: DENV infections are common among close community contacts of hospitalized dengue patients. The high number of asymptomatic infections and the observation that viremia precedes the onset of fever for up to seven days highlight the importance of unrecognized dengue transmission and the need for improved transmission control.

Performance of a Point-of-Care Fluorescence Immunoassay Test to Measure the Anti-Severe Acute Respiratory Syndrome Corona Virus 2 Spike, Receptor Binding Domain Antibody Level.

Quantitative determination of anti-SARS-CoV2-S-RBD is necessary for the evaluation of vaccination effectiveness. The surrogate viral neutralization test (SVNT) is approved for measuring anti-SARS-CoV2-S-RBD, but a point-of-care platform is needed to simplify anti-SARS-CoV-2-S-RBD measurement. We aimed to evaluate the performance of a rapid fluorescent immunoassay-based kit, FastBio-RBDTM, compared to the SVNT. During April-September 2021, we enrolled two groups of subjects, convalescent subjects and subjects without a COVID-19 history. The subjects were tested for the anti-SARS-CoV2-S-RBD antibody using FastBio-RBDTM and the GenScript-cPASSTM SVNT. We measured the correlation coefficient and conducted an ROC analysis to determine the best cut-off value of anti-SARS-CoV2-S-RBD against the SVNT percent inhibition levels of 30% and 60%. We included 109 subjects. Anti-SARS-CoV-2-S-RBD strongly correlated to SVNT % inhibition with an R value of 0.866 (p < 0.0001). The ROC analysis showed that the anti-SARS-CoV-2-S-RBD of 6.71 AU/mL had 95.7% sensitivity and 87.5% specificity to detect a percentage inhibition of 30%. The anti-SARS-CoV-2-S-RBD of 59.76 AU/mL had a sensitivity of 88.1% and specificity of 97.0% to detect a percentage inhibition of 60%. FastBio-RBDTM could determine the presence and level of anti-SARS-CoV-2-S-RBD with good sensitivity and specificity. It has the potential to be deployed in health facilities with limited resources.

Antibody Response to SARS-CoV-2 Vaccination in Patients with End-Stage Kidney Disease on Hemodialysis.

Patients with end-stage kidney disease on hemodialysis (ESKD-HD) have a high risk of contracting severe COVID-19. Vaccination can help reduce disease severity, but the immune dysregulation observed in these patients may result in an inadequate antibody response. Therefore, we aimed to evaluate the immune response postvaccination in ESKD-HD patients. This prospective cohort study was conducted in two hemodialysis centers in Indonesia. We enrolled ESKD-HD patients (n = 143) pre- and postvaccination and compared them to healthy subjects (n = 67). SARS-CoV-2 antibody response was assessed using anti-S-RBD antibodies and SVNT % inhibition tests. We performed bivariate and multivariate analysis to determine factors associated with SARS-CoV-2 antibody levels. Seropositive conversion was observed in 97% ESKD-HD subjects postvaccination. Compared with healthy subjects, ESKD-HD patients showed a comparable anti-S-RBD antibody titer postvaccination. mRNA vaccines remained a significant factor for the high immune response, while hypoalbuminemia correlated with lower immune response. In conclusion, ESKD-HD patients showed a robust immune response postvaccination. mRNA vaccines induced a stronger antibody response than other vaccines. Lower levels of serum albumin correlate with lower immune responses in ESKD-HD patients after vaccination.

Central nervous system infection in a pediatric population in West Java.

Central nervous system (CNS) viral infections are critical causes of morbidity and mortality in children; however, comprehensive data on etiology is lacking in developing countries such as Indonesia. To study the etiology of CNS infections in a pediatric population, 50 children admitted to two hospitals in Bandung, West Java, during 2017-2018 were enrolled in a CNS infection study. Cerebrospinal fluid and serum specimens were tested using molecular, serological, and virus isolation platforms for a number of viral and bacteriological agents. Causal pathogens were identified in 10 out of 50 (20%) and included cytomegalovirus (n = 4), Streptococcus pneumoniae (n = 2), tuberculosis (n = 2), Salmonella serotype Typhi (n = 1) and dengue virus (n = 1). Our study highlights the importance of using a wide range of molecular and serological detection methods to identify CNS pathogens, as well as the challenges of establishing the etiology of CNS infections in pediatric populations of countries with limited laboratory capacity.

Development of Nucleic Acid Lateral Flow Immunoassay for Rapid and Accurate Detection of Chikungunya Virus in Indonesia.

Chikungunya fever is an arboviral disease caused by the Chikungunya virus (CHIKV). The disease has similar clinical manifestations with other acute febrile illnesses which complicates differential diagnosis in low-resource settings. We aimed to develop a rapid test for CHIKV detection based on the nucleic acid lateral flow immunoassay technology. The system consists of a primer set that recognizes the E1 region of the CHIKV genome and test strips in an enclosed cassette which are used to detect amplicons labeled with FITC/biotin. Amplification of the viral genome was done using open-source PCR, a low-cost open-source thermal cycler. Assay performance was evaluated using a panel of RNA isolated from patients' blood with confirmed CHIKV (n = 8) and dengue virus (n = 20) infection. The open-source PCR-NALFIA platform had a limit of detection of 10 RNA copies/ml. The assay had a sensitivity and specificity of 100% (95% CI: 67.56% - 100%) and 100% (95% CI: 83.89% - 100%), respectively, compared to reference standards of any positive virus culture on C6/36 cell lines and/or qRT-PCR. Further evaluation of its performance using a larger sample size may provide important data to extend its usefulness, especially its utilization in the peripheral healthcare facilities with scarce resources and outbreak situations.

A novel diagnostic algorithm equipped on an automated hematology analyzer to differentiate between common causes of febrile illness in Southeast Asia.

BACKGROUND: Distinguishing arboviral infections from bacterial causes of febrile illness is of great importance for clinical management. The Infection Manager System (IMS) is a novel diagnostic algorithm equipped on a Sysmex hematology analyzer that evaluates the host response using novel techniques that quantify cellular activation and cell membrane composition. The aim of this study was to train and validate the IMS to differentiate between arboviral and common bacterial infections in Southeast Asia and compare its performance against C-reactive protein (CRP) and procalcitonin (PCT). METHODOLOGY/PRINCIPAL FINDINGS: 600 adult Indonesian patients with acute febrile illness were enrolled in a prospective cohort study and analyzed using a structured diagnostic protocol. The IMS was first trained on the first 200 patients and subsequently validated using the complete cohort. A definite infectious etiology could be determined in 190 of 463 evaluable patients (41%), including 89 arboviral infections (81 dengue and 8 chikungunya), 94 bacterial infections (26 murine typhus, 16 salmonellosis, 6 leptospirosis and 46 cosmopolitan bacterial infections), 3 concomitant arboviral-bacterial infections, and 4 malaria infections. The IMS detected inflammation in all but two participants. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the IMS for arboviral infections were 69.7%, 97.9%, 96.9%, and 77.3%, respectively, and for bacterial infections 77.7%, 93.3%, 92.4%, and 79.8%. Inflammation remained unclassified in 19.1% and 22.5% of patients with a proven bacterial or arboviral infection. When cases of unclassified inflammation were grouped in the bacterial etiology group, the NPV for bacterial infection was 95.5%. IMS performed comparable to CRP and outperformed PCT in this cohort. CONCLUSIONS/SIGNIFICANCE: The IMS is an automated, easy to use, novel diagnostic tool that allows rapid differentiation between common causes of febrile illness in Southeast Asia.

Detection and identification of coxsackievirus B3 from sera of an Indonesian patient with undifferentiated febrile illness.

INTRODUCTION: Coxsackievirus B3 (CVB3) virus has been implicated as the causative agent of various outbreaks of clinical disease, including hand, foot, and mouth diseases, aseptic meningitis, acute myocarditis, and inflammatory cardiomyopathy. METHODOLOGY: Two hundred and nine undiagnosed cryopreserved specimens obtained from factory workers in Bandung, Indonesia, who displayed symptoms of acute febrile illness were gathered. Total RNA was isolated from serum and tested by conventional polymerase chain reaction (PCR) using Enterovirus genus-level primers and confirmed by sequencing. Concurrently, the virus was isolated in LLC-MK2 cells. RESULTS: CVB3 virus was identified in an archived specimen from a patient who presented with symptoms of fever, headache, myalgia, and nausea. Sequencing results of the VP1 region from both the clinical sample and tissue culture supernatant showed 97% homology to a CVB3 virus isolate from Taiwan. Virus propagation in LLC-MK2 cell culture exhibited severe cytopathic effects two days post-inoculation. CONCLUSIONS: We report the first case of CVB3 from an undifferentiated febrile illness specimen from Indonesia.