Search Results (306)

Background: This study aimed to assess the prevalence of SARS-CoV-2 infection, vaccination, and immune status among a population, both Dentists and University Professors, within a clinical setting at one and at 12 months after COVID-19 vaccination. Methods: A cross-sectional study involving 47 professionals (aged 27–52) was conducted in the University Fernando Pessoa. Participants completed an online survey on SARS-CoV-2 infection status and vaccination, received and provided plasma samples for serological analysis. The protocol was approved by the UFP-Ethics Committee. Anti-S1-RBD SARS-CoV-2 IgM and IgG antibody titration values (AU/mL) were measured, by enzyme-linked-immunosorbent assay (ELISA), with reactive immunoglobulins (Ig) seropositivity for values ≥1 AU/mL. Results: SARS-CoV-2 infection rate increased from 8.5% in July 2021 to 48.9% in June 2022, with 8.5% experiencing reinfection. Vaccination rate was 91.5% by July 2021 and increased slightly to 93.6% by June 2022; 72.3% of the sample received a third dose. IgG seropositivity increased from 91.5% to 95.7% in June 2022. After one-year, significant associations were found between IgG seropositivity and both participant’s age (p = 0.009; <50 years) and vaccine doses (p = 0.003; 1–3 doses) received. Conclusions: SARS-CoV-2 infection rate, vaccination, and IgG seropositivity rates were high and increased over one year. The age and vaccination status were associated with the immunity status at 12th month follow-up. Findings highlight variability in IgG seroprevalence due to multiple influencing factors, which justifies future studies. Full article

Background: Vaccination effectively reduces the risk of infection, including COVID-19 yet older adults often receive insufficient attention despite their increased vulnerability. The study aimed to correlate serological results with underlying conditions, vaccination status, and COVID-19 history. Methods: This non-interventional, multicenter study aimed to assess vaccination coverage and SARS-CoV-2 antibody levels among residents of eight long-term care facilities (LTCFs) in Southern Poland. Data collection took place between January and June 2022, with 429 participants recruited based on their ability to provide informed consent and their residency in LTCFs. Sociodemographic data, medical history, and COVID-19-related information—including infection history and vaccination status—were collected through surveys. Blood samples were obtained for serological testing using enzyme-linked immunosorbent assays (ELISA) to detect anti-SARS-CoV-2 antibodies. Statistical analysis, including Spearman’s correlation, revealed significant associations between antibody levels and vaccination status, as well as between RT-PCR-confirmed COVID-19 infections and higher antibody titers. Results: Among the seven different qualitative serological, only the Anti-SARS-CoV-2 NCP (IgG) and Anti-SARS-CoV-2 (IgA) tests showed a positive correlation with the Anti-SARS-CoV-2 QuantiVac (IgG) test, which was used as a comparator. A weak correlation was noted with the age of the residents. Conclusions: Our findings suggest that vaccination positively influences antibody responses, underscoring the importance of immunization among LTCF residents. Additionally, certain comorbidities—such as degenerative joint disease and diabetes—showed weak correlations with higher antibody levels. This study provides valuable insights into the humoral immune response to COVID-19 in vulnerable populations residing in LTCFs. Full article

(1) Background: The ongoing global health threat posed by SARS-CoV-2 requires reliable and accessible diagnostic tools, especially in resource-limited settings where RT-qPCR may be impractical. This study describes the development and validation of two enzyme-linked immunosorbent assays (ELISA) designed to detect anti-SARS-CoV-2 IgG antibodies employing recombinant S1 and S2 spike protein subunits. (2) Methods: The assays were optimized and validated using serum samples from 354 RT-qPCR-confirmed hospitalized patients and 337 pre-pandemic blood donors. (3) Results: The S1-based ELISA achieved a 52.8% sensitivity and a specificity of 93.5%, with an area under the ROC curve (AUC) of 71.6%. In contrast, the S2-based ELISA demonstrated superior diagnostic performance, with a sensitivity of 63.7%, a specificity of 99.7%, and an AUC of 83.1%. Cross-reactivity analysis using sera from individuals with unrelated infectious diseases confirmed the high specificity of the S2-ELISA. Time-stratified analysis revealed that sensitivity increased with time, peaking between 15 and 21 days post-symptom onset. Compared to commercial serological assays, the S2-ELISA demonstrated comparable or improved performance, particularly in specificity and diagnostic odds ratio. (4) Conclusions: The S2-ELISA offers a robust, highly specific, and operationally simple tool for serological detection of SARS-CoV-2 infection. Its strong diagnostic performance and accessibility make it well-suited for implementation in diverse epidemiological settings, particularly where molecular testing is limited. The development of affordable, validated serological assays such as this is critical for strengthening surveillance, understanding transmission dynamics, and informing public health responses. Full article

Celiac disease (CD), a human leukocyte antigen-associated disorder, is caused by gluten sensitivity and is characterized by mucosal alterations in the small intestine. Currently, its diagnosis involves the determination of serological markers. The traditional method for clinically determining these markers is the enzyme-linked immunosorbent assay. However, immunosensors offer sensitivity and facilitate the development of miniaturized and portable analytical systems. This work focuses on developing an amperometric immunosensor for the quantification of IgA antibodies against tissue transglutaminase (IgA anti-TGA) in human serum samples, providing information on a critical biomarker for CD diagnosis. The electrochemical device was designed on a polyimide substrate using a novel solid ink of wax and carbon nanofibers (CNFs). The working electrode microzone was defined by incorporating aminofunctionalized TiO₂ nanoparticles (TiO₂NPs). The interactions and morphology of CNFs/wax and TiO₂NPs/CNFs/wax electrodes were assessed through different characterization techniques. Furthermore, the device was electrochemically characterized, demonstrating that the incorporation of CNFs into the wax matrix significantly enhanced its conductivity and increased the active surface area of the electrode, while TiO₂NPs contributed to the immunoreaction area. The developed device exhibited remarkable sensitivity, selectivity, and reproducibility. These results indicate that the fabricated device is a robust and reliable tool for the precise serological diagnosis of CD. Full article

Background: The Human Papillomavirus (HPV) vaccine generates high antibody titers against targeted HPV types. This study investigated vaccine-induced anti-HPV18 immunoglobulin (IgG) antibody titers and subsequent HPV18/45 infections. Methods: We performed a nested matched case-control study leveraging a prospective longitudinal cohort of adolescent and young adult women (AYW) vaccinated with the quadrivalent HPV vaccine (4vHPV) attending the Mount Sinai Adolescent Health Center (MSAHC) in Manhattan, NY. The case individuals included AYW who had an incident detection of cervical HPV18 (n = 3) or HPV45 (n = 34) DNA after vaccination and were compared to two vaccinated control individuals (HPV18/45-negative); one random control (RC, n = 37) and one high-risk control (HRC, n = 37) selected from the upper quartile of a sexual risk behavior score. Serological titers against HPV18 were measured by end-point dilution and enzyme-linked immunosorbent assay (ELISA) in serum collected before the incident detection of HPV. Matching was performed based on age at first dose, follow-up time, and sexual risk behavior score. Conditional logistic regression was used to assess the association between case-control status and anti-HPV antibody titers, consistent with the matched-pair design. Results: Antibody titers for HPV18 were most different between AYW who developed an HPV18/45 infection compared to high-risk controls OR = 1.66, 95% CI: 0.96–2.85 (p = 0.1629). Analyses of pooled data from vaccinated recipients including who developed HPV16/31 or HPV18/45 infections demonstrated that the odds of a one-log unit increase in anti-HPV16 or 18 antibody titers, respectively, were 40% higher in the combined control groups (RC + HRC, n = 160) (OR = 1.40, 95% CI: 1.09–1.79, p = 0.0135) and 73% higher in the HRC (n = 80) (OR 1.73, 95% CI: 1.34, 2.52, p = 0.0117) compared to HPV16/18/31/45 cases (n = 80). Conclusions: Overall, these findings suggest that higher IgG antibodies to HPV16/18 after vaccination represent an increased likelihood of protection from homologous and cross-reactive HPV types (HPV16/18/31/45). These results show that differences in antibody titers are associated with breakthrough infection after vaccination, suggesting that further study of long-term antibody titers and infection should be pursued. Full article

Background/Objectives: Measles, mumps, and rubella (MMR) continue to pose a significant public health challenge due to insufficient immunization coverage. This study aimed to provide the first seroprevalence data against MMR and to explore self-reported immunity among future healthcare workers (HCWs) in Serbia, including women of childbearing age. Methods: We included 1296 future health care workers (HCWs) aged 19 to 29, born in Serbia. All HCWs supplied a blood sample for serology and filled in a questionnaire. Antibodies were measured using an enzyme immunoassay against measles, mumps, and rubella (MMR). Results: Anti-measles, -mumps, and -rubella seronegativity rates were 25.6%, 26.5%, and 4.4%, respectively, among future HCWs in Serbia. The mumps seronegativity rate was significantly higher in the oldest (27–29-year) age group, accompanied by significantly lower anti-mumps IgG GMCs in the same age group compared to younger participants (p = 0.035 and p < 0.001, respectively). Anti-mumps seronegativity also increased significantly across birth cohorts, from the youngest to the oldest (p = 0.004). Furthermore, anti-mumps IgG antibody GMCs were significantly higher among females, those who attended nursery/kindergarten, and unvaccinated individuals (p = 0.050, p = 0.020, and p = 0.005, respectively). Finally, older age and unvaccinated status were identified as independent factors associated with anti-measles and anti-mumps seronegativity among future HCWs in Serbia. Conclusions: The cross-sectional seroprevalence data revealed insufficient seroprotection in this population of particular importance, i.e., future HCWs, and women of childbearing age. These results strongly support the national recommendations for the mandatory vaccination of these populations. Identified immunity gaps should be closed promptly by strategic, targeted serologic screening, followed by vaccination of those lacking MMR antibodies. Full article

Infectious bursal disease virus (IBDV) is one of the most important immunosuppressive viruses in poultry, causing the global spread of infectious bursal disease (IBD). It poses a significant threat to the healthy development of the poultry industry. Vaccination is an effective approach for controlling IBDV infection. Therefore, reliable immune monitoring for IBDV is critical for maintaining poultry health. The enzyme-linked immunosorbent assay (ELISA) is a common technique used to detect specific antibodies in clinical serum testing and for the serological evaluation of IBDV vaccines. Among the currently available and under development IBDV vaccines, IBD VP2 subunit-based vaccines account for a considerable proportion. These vaccines stimulate the production of antibodies that are specific only to VP2. However, most IBDV antibody ELISA kits approved for use have applied the whole virus as the coating antigen, which does not adequately meet the diverse requirements for IBDV detection across different conditions. This study utilized a prokaryotic expression system to express the VP2 protein of the IBDV epidemic strain, assembling it into virus-like particles to be used as coating antigens. This approach enabled the establishment of an indirect ELISA method for detecting IBDV VP2 antibody (VP2-ELISA). The optimal coated antigen concentration was determined to be 2.5 μg/mL, with overnight coating at 4 °C; sealing with 5% skim milk at 37 °C for 4 h; serum dilution at 1:500 with incubation at 37 °C for 30 min; secondary antibody dilution at 1:4000 with incubation at 37 °C for 40 min; and then incubation with the substrate solution 3,3′,5,5′-tetramethylbenzidine at room temperature for 20 min. The criterion for interpreting the detection results was OD_450nm ≥ 0.111 indicates IBDV antibody positivity, while OD_450nm < 0.111 indicates negativity. The established VP2-ELISA can specifically detect IBDV-positive sera at the lowest serum dilution of 1:6400, with intra- and inter-batch coefficients of variation of <2%. This indicates that the VP2-ELISA exhibits good specificity, sensitivity, and stability. Detection experiments using 20 laboratory-immunized chicken serum samples and 273 clinical serum samples demonstrated that the results of VP2-ELISA were consistent with those of commercial ELISA kits coated with whole virus. In summary, the VP2-ELISA developed in this study offers advantages in immune response detection for IBD VP2 subunit-based vaccines and is appropriate for evaluating the efficacy of IBD vaccines and detecting clinical serum samples. Full article

Oral Lichen Planus (OLP) is a chronic autoimmune disease with potential overlap with Pemphigus Vulgaris (PV), particularly in erosive forms. Desmoglein 1 and 3 are transmembrane glycoproteins of desmosomes, typically involved in PV. This scoping review aims to evaluate the presence and potential pathogenetic role of anti-desmoglein 1 (Dsg1) and anti-desmoglein 3 (Dsg3) antibodies in OLP. A literature search was conducted on MEDLINE/PubMed, Ovid, and Scopus up to April 2025. Human studies reporting OLP patients with anti-Dsg1 and/or anti-Dsg3 antibodies were included. Data from 11 studies were analyzed by diagnosis, age/sex, oral site involvement, immunofluorescence, and ELISA testing. Erosive OLP was most frequently associated with anti-Dsg1/Dsg3 positivity, mainly in women aged 40–60. Immunofluorescence was positive in some cases, while the ELISA test almost consistently detected anti-Dsg1 and Dsg3 antibodies. However, in many instances, antibody titers did not reach the threshold value, despite the presence being detectable. This finding suggests that anti-Dsg1/Dsg3 antibodies may represent epiphenomena of chronic inflammation in erosive OLP, indicating an immune-serological overlap with PV but lacking direct pathogenicity. Furthermore, the role of Dsg3 in oral squamous cell carcinoma, by promoting enzymes that degrade the extracellular matrix and enhance tumor invasiveness, highlights the complex functions of desmogleins beyond autoimmunity. Full article

Infections with the Hepatitis B (HBV) and Hepatitis C (HCV) viruses share some transmission routes, which is why coinfection with these viruses becomes common, especially in endemic areas. This study evaluated the immunological response profile, viral load, and liver damage in groups monoinfected with HBV or HCV and in those co-infected with HBV/HCV. The groups were composed of 22 patients monoinfected by HCV, 22 patients monoinfected by HBV, and 34 co-infected by HBV/HCV, according to serological markers and molecular biology tests. The study was carried out from December 2017 to October 2019. Virus detection employed enzyme immunoassay, Enzyme-Linked Immunosorbent Assay (ELISA), and real-time PCR, while liver function and fibrosis were assessed using biochemical tests and Fibroscan. To research the immunological profile, cytokines were quantified using the BIO-Plex Pro Human Cytokine. Comparing the groups, both mono- and co-infected patients exhibited a Th1 immune response profile. HCV monoinfection notably showed significantly elevated serum levels of INF-γ (p < 0.01) and TNF-α (p < 0.01). The viral load was significantly higher in the HCV monoinfected group when compared to the other groups. Regarding liver damage, patients with a high level of fibrosis (F4) presented significant levels of cytokines INF-γ (p < 0.001), IL-17 (p < 0.0001), and TNF-α (p < 0.0001). Full article

The increasing number of owned and stray dogs in large cities is becoming a pressing issue due to rising population densities, urban conditions, and poor control over animal reproduction. This situation poses serious epidemiological risks, as dogs can act as reservoirs and transmitters of infectious and parasitic diseases dangerous to humans. This study aimed to investigate the prevalence and carriage of infectious and parasitic diseases in stray dogs in the city of Uralsk as a factor of epidemiological risk. In 2024, 1213 stray dogs were captured from different city districts and examined at the veterinary clinic and laboratory of Zhangir Khan University. Biological samples (blood, urine, feces) from 10% of the animals were analyzed using molecular (PCR), serological (ELISA), and helminthological methods. Serological and molecular analyses revealed the widespread circulation of bacterial pathogens. Antibodies to additional bacterial agents, including Pasteurella multocida, Mycobacterium spp., Listeria monocytogenes, and Leptospira spp., were detected in the samples, indicating an unfavorable sanitary and epidemiological situation in the urban environment. An enzyme-linked immunosorbent assay (ELISA) identified antibodies against Toxocara canis in 50.9% of the dogs and against Echinococcus granulosus in 76.4%, reflecting both active and past infections. The polymerase chain reaction (PCR) results showed the presence of Brucella canis DNA in blood and urine samples, while antibodies to Brucella spp. were detected in 57.8% of the examined dogs, underscoring the significant zooanthroponotic importance of this pathogen and its potential threat to human health. Additionally, T. canis DNA was found in 39.2% of the samples and E. granulosus DNA in 16.6%. A helminthological examination using the Fülleborn method revealed a high rate of helminth infection: Ancylostoma caninum—35.3%, T. canis—32.3%, and Toxascaris leonina—29.4%. The obtained results highlight the significant role of stray dogs as epizootiological and epidemiological reservoirs of zooanthroponotic infections. This poses a serious threat to public health and necessitates the implementation of effective control and prevention measures for infectious and parasitic diseases within urban fauna. Full article

Background/Objectives: Syphilis remains a significant public health challenge worldwide. Accurate and efficient diagnostic tools are essential to controlling the spread of the disease. Current diagnostic approaches primarily rely on serologic treponemal tests (TTs) and nontreponemal tests (NTTs). The aim of this study was to evaluate the diagnostic properties of various serological methods for syphilis diagnosis. Methods: Samples were collected from participants of the Health, Information, and Sexually Transmitted Infection Monitoring (SIM study) between March 2020 and May 2023, using convenience sampling at a mobile health unit in Porto Alegre, Brazil. A total of 250 individuals were tested using the point-of-care (POC) lateral flow treponemal test, Venereal Disease Research Laboratory (VDRL) test, Rapid Plasma Reagin (RPR) test, Enzyme-Linked Immunosorbent Assay (ELISA), and Treponema pallidum hemagglutination assay (TPHA). Of these, 125 participants tested positive for syphilis in the POC screening. Diagnostic properties such as sensitivity, specificity, and predictive values were assessed for the POC test, ELISA, and VDRL test. The TPHA was used as the reference standard for the TT, and the RPR test as the reference standard for the NTT. Results: Among individuals with positive POC test results, 97.6% (122/125) were also positive by the ELISA, and 85.6% (107/125) were positive by the TPHA. Additionally, 48.0% (60/125) and 42.4% (53/125) tested positive by the VDRL and RPR tests, respectively. Using the TPHA as a reference, TT tests showed sensitivities of 97–98% and specificities of 93–95% for detecting anti-Treponema pallidum antibodies using the ELISA and POC test, respectively. For the NTT, the VDRL test demonstrated a sensitivity of 98% and a specificity of 95% compared to the RPR test. The kappa coefficients were 0.85 for the POC test vs. the TPHA, 0.81 for the ELISA vs. the TPHA, and 0.89 for the VDRL vs. the RPR tests, indicating substantial agreement. Conclusions: This study highlights a good diagnostic performance and high agreement levels among the evaluated serological tests for syphilis, reinforcing their utility in clinical and public health settings, as well as epidemiological studies. Full article

Standard serological tests post-vaccination, such as enzyme-linked immunosorbent assay (ELISA), complement fixation, and virus neutralization, are crucial for monitoring African horse sickness (AHS). However, the availability of commercial test kits such as blocking ELISA varies by regions; while they are commonly used in Africa and Europe, their limited availability and high cost in Thailand present significant challenges. Therefore, this study aimed to evaluate an alternative approach using an in-house indirect ELISA based on cell-based monovalent and polyvalent strains of live attenuated AHS virus. This method addresses the cost and accessibility issues faced in Thailand. This study demonstrated promising results: the in-house indirect ELISA showed analytical sensitivity and specificity values of 88.30% and 67.02% for monovalent strains and 87.23% and 84.04% for polyvalent strains, respectively, compared to the blocking ELISA. These findings underscore the efficacy of the in-house ELISA as a viable serodiagnostic tool for AHS. Furthermore, the polyvalent antigen-based in-house indirect ELISA proved to be a reliable alternative for AHS monitoring, particularly in vaccinated horses, offering enhanced specificity. Additionally, this method is simpler, cheaper, faster, and more convenient than blocking ELISA and serum neutralization tests, making it a practical choice for routine AHS surveillance. Full article

With the first evidence of the association between bats and influenza A viruses, various studies have begun to emerge to understand this interesting and important association among bats conservation, animal health, and public health. This study aimed to verify the presence of anti-influenza A vipothesrus antibodies, as well as the molecular identification of these viruses in bats distributed in forest fragments located in southeastern Mexico. Blood samples were obtained from 600 bats belonging to 24 different species, using an enzyme immunoassay to detect antibodies against the nucleoprotein antigen of the avian influenza A virus. Likewise, oropharyngeal swabs, rectal swabs and organs were taken for quantitative reverse transcription PCR (qRT-PCR) of these viruses. A total of six bats (1%) tested positive either by serology or molecular methods, not both simultaneously. Although this suggests a very low prevalence of influenza A viruses in Mexican bats, it is the first study to address this association and, following the precautionary principle, we consider it necessary to establish systematic monitoring of the presence of influenza A in bats, since they are known to harbor infectious agents with zoonotic potential. Furthermore, it is possible that the association of influenza A viruses circulating in Latin American bats has an important co-evolutionary component with some bat species with exclusive distribution in the American continent. Full article

Italy was one of the first countries to implement a hepatitis B (HBV) immunization strategy in 1991; since its introduction, the epidemiology of this disease has significantly changed. The aim of this retrospective study was to assess the seroprevalence of three HBV markers (anti-HBs, anti-HBc, and HBsAg) and describe the acquired immunity in a representative sample of the adult general population in the province of Florence (Italy) between April 2018 and December 2019. We conducted an enzyme-linked immunosorbent assay on 430 serum samples collected from the adult general population to quantify anti-HBs titers and assess the presence of anti-HBc and HBsAg. For the interpretation of hepatitis B serologic results, we referred to the US CDC guidelines. We conducted two multivariate logistic regression analyses (applied to the entire enrolled population and to the unvaccinated) to assess predictors of immunity against HBV using sex, age, and nationality as predictors. The overall anti-HBs prevalence was 30%, with a significant decreasing trend in seropositivity with increasing age. The overall anti-HBc prevalence was 11.6%, with seropositivity increasing with age. Only one subject tested positive for HBsAg (0.2%). Approximately 67.4% (290/430) of the study population was susceptible, 20.9% (90/430) was vaccinated, 9.1% (39/430) had naturally acquired immunity, and 0.2% (1/430) had an acute infection. Older age and foreign nationality were identified as risk factors in both multivariate logistic regression models. The comparison highlights a reduction in the circulation of HBV infection markers (anti-HBc and HBsAg) over 30 years in Tuscany, particularly in younger age groups. Our seroprevalence study demonstrated a good level of protection against hepatitis B, primarily among individuals under 40 years old, the target group of the vaccination strategy. Full article

Background/Objectives: Hepatitis E virus (HEV) is one of the leading causes of acute hepatitis, with immunosuppressed individuals, such as oncology patients, being particularly vulnerable to chronic infections that may progress to liver disease or fatal outcomes. Assay variability complicates HEV prevalence assessment in at-risk groups. This study aimed to compare the reliability and concordance of three HEV antibody assays—Wantai, Euroimmun, and Elecsys^®—in immunosuppressed oncology patients. Methods: In this prospective pilot study, serum samples were obtained from oncology patients between September 2020 and October 2021. Samples were collected both at baseline (treatment-naive) and during ongoing treatment. A healthy control group was retrospectively included for comparative analysis. Anti-HEV IgM and IgG antibodies were tested in all samples using enzyme-linked immunosorbent assays (Wantai, Euroimmun) and an electrochemiluminescence immunoassay (Elecsys^®). Demographic and clinical data, along with information on HEV risk factors, were extracted from medical records and patient questionnaires. Results: HEV IgM prevalence ranged from 0% (Wantai) to 6% (Elecsys^®), while IgG prevalence was 12% (Euroimmun), 38% (Wantai), and 53% (Elecsys^®). Concordance was poor, with Cohen’s Kappa values indicating slight to moderate agreement (κ = 0.000–0.553). Patients with hematological malignancies exhibited the highest IgG seroprevalence. Risk factor analysis revealed the highest association between HEV exposure and the consumption of undercooked pork or crop-based agriculture. Conclusions: Significant variability among HEV serological assays highlights the challenges of reliable HEV diagnostics in immunosuppressed oncology patients. Assay selection and improved testing strategies are critical for this high-risk group. Full article