The level of significance was indicated at 5%. Results CL-900i? Chemiluminescence Immunoassay Specificity/Cross-Reactivity with DENV-IgG The 90 DENV-IgG-positive and 90 DENV-IgG-negative prepandemic sera samples were tested by the CL-900i? SARS-CoV-2-IgG kit (Table ?(Table1).1). positives, 47 negatives, and 1 equivocal for DENV-IgG, whereas the SARS-CoV-2-IgG-negative sera resulted in 50 positives, 40 negatives, and 1 equivocal for DENV-IgG. No statistically significant difference in the proportion that is DENV-IgG positive between the SARS-CoV-2-IgG-positive and SARS-CoV-2-IgG-negative sera (value = 0.58). In conclusion, there is a low risk of serological cross-reactivity between the DENV and SARS-CoV-2-IgG antibodies when using advanced detection assays. family; it has four genetically and antigenically serotypes (DENV-1, DENV-2, DENV-3, and DENV-4). The virus is transmitted to humans via a bite of an infected mosquito, usually from and species, causing dengue disease [6]. According to the World Health Organization (WHO), dengue disease is usually a major health concern in many regions, including Africa, the Americas, the Eastern Mediterranean, South-East Asia, and the Western Pacific [7]. The simultaneous occurrence of COVID-19 pandemic and dengue disease in DENV endemic countries has doubled the burden on the healthcare system in these regions, having to face two complex diseases with Lactitol shared clinical and diagnostic features [8]. The clinical symptoms of dengue and COVID-19 are comparable, including cough, fever, skin rash, and fatigue, which makes it challenging to differentiate between the two viral infections and might lead to misdiagnosis [9]. These observations raised a lot of speculations regarding the possibility that preexposure to DENV might provide cross-protection immunity to SARS-CoV-2 contamination [8]. That is, SARS-CoV-2 has antigenic similarity to DENV and elicits Lactitol antibodies that are detected by DENV serological assessments. The first reported cases of serological cross-reactivity between COVID-19 and DENV were from Singapore. These cases were DENV-IgM and IgG false positive by rapid lateral flow assay (LFA). However, further testing of the original samples showed that this patients were unfavorable for DENV by RT-PCR, and a repeat DENV rapid test was also unfavorable, but RT-PCR positive for Rabbit polyclonal to Neuron-specific class III beta Tubulin SARS-COV-2. Thus, the initial DENV seroconversion results were considered false positive [10]. Several other studies have reported serological cross-reactivity of the immune responses between SARS-CoV-2 and DENV [2, 9]. Most of the available studies are based on point-of-care rapid testing kits [11, 12, 13, 14]. However, some rapid test kits have low specificity and can generate false positives [15]. Therefore, we aimed to investigate potential serological cross-reactivity between SARS-CoV-2 and DENV-IgG antibodies using advanced assays including chemiluminescence immunoassay and enzyme-linked immunosorbent assay (ELISA) test. Methods Study Design A total of 91 SARS-CoV-2-IgG-positive and 91 IgG-negative postpandemic sera confirmed by RT-PCR (total = 182) were available from a recent study [16]. In addition, 90 DENV-IgG sero confirmed positive and 90 DENV-IgG sero confirmed unfavorable (total = 180) were available from a study conducted before the SARS-CoV-2 pandemic [17]. Therefore, the 91 SARS-CoV-2-unfavorable sera and the 90 DENV-negative sera were selected as the control group for the ELISA and Lactitol the automated analyzer assay testing. Specimens were collected from males, 24C69 years of age, and nationalities of African, Asian, and Middle Eastern origins, all of them residing currently in Qatar. Study Participants Complete descriptions of the origin of the samples can be found in these articles [18]. These were an opportunistic cross-sectional study on blood donor volunteers from different nationalities attending the Blood Donation Center at Hamad Medical Corporation, the main healthcare provider in Qatar, between June 2013 and June 2017. Blood donation in Qatar is usually a common practice, and individuals from diverse socioeconomic strata participate in blood donation campaigns. Round 6,000 blood donors consented to provide blood specimens and basic demographic information, including Lactitol sex, age, and nationality. No identifiable information was collected. The research work was approved by the Ethics Boards and Research Committees at Hamad Medical Corporation and Qatar University. The samples contain Qataris and expatriates (MENA and non-MENA nationals) residing in Qatar, adults 18 years of age. The number of female participants was small, and consequently, women were excluded. Positive and negative anti-dengue samples used in this study were randomly selected based on the results of our previous.