The complex coincidence of several immunopathological, socio-cultural, and health infrastructure factors may affect the COVID-19 related mortality among different populations. The impact of the age on disease progression has been confirmed in several studies. Recently limited ecological and clinical studies have sparked controversy among researchers about the protective impact of the non-specific effect of routinely used Bacille Calmette-Guerin (BCG), Hepatitis A virus (HAV), and influenza (Flu) vaccines or their natural infections against COVID-19. In the present study, variables, including BCG vaccination coverage, HAV prevalence, and population age distributions, from 59 countries were analyzed to examine their potential association with COVID-19 infection and related mortality rate. Concerning COVID-19 cases/million population (1MP) and mortality, there are significant differences between countries with and without BCG vaccination programs (p-value <0.001). A significant negative correlation between both BCG coverage and HAV prevalence with COVID-19 related mortality was also found (r (59)=-0.4, p-value <0.05), (r (59) =-0.3, p-value <0.01). Based on the results of the present study, previous ecological analyses and available epidemiological evidence, along with knowledge of the immune response to BCG, HAV and influenza vaccination, as well as COVID-19 infection progression, the current study suggest a hypothesis that IFN-γ induced immune response which could be triggered by BCG, HAV, and flu vaccination or natural infections may have a protective effect against COVID-19 related mortality.
Background and Objective
Rapid on-site testing with low sample volume and point-of-care diagnostics are very useful for preventive measures against hepatitis B virus. Therefore, the aim of this study is to develop a rapid, accurate, and cost-effective lateral flow biosensor for convenient HBV nucleic acid detection at the point-of-care.
Methods
Clinical serum samples with HBV-positive real-time PCR assays were used for the experiments. Spin column nucleic acid purification and serum heat treatment were used for sample preparation. A 250 bp fragment of the HBV polymerase gene was amplified with 3 pairs of specific biotin- and FITC-labeled LAMP primers. Different incubation temperatures (64-68° C) and times (30 min, 45 min, and 1 h) were explored for optimal LAMP assay, and results were assessed by fluorometric analysis, white turbidity, and lateral flow assay. Ready-to-use Milenia HybriDetect1 strips were used to visualize the LAMP amplicons. Subsequently, 10-fold serial dilutions of a secondary standard containing 108 IU/ml viral load were used to evaluate lateral flow biosensor performance.
Results
The LAMP reaction was optimized at 67 ◦C, and appreciable turbidity was achieved after 30 minutes of incubation. Templates from 108 IU/ml to 101 IU/ml exhibited distinct test bands when spin column approach was used as the purification method. However, the minimum viral load detectable by lateral flow was 103 IU/ml when serum samples were treated with heat and the supernatant was directly used for LAMP. The result shows that the developed LAMP-LF assay was able to detect a viral load of 101 IU/ml only in 66.6% of cases.
Conclusion
The LAMP-LF assay is a potential solution for HBV testing in resource-limited settings. Overall, our study demonstrated that the integration of LAMP - LF assay can be a plausible approach for point-of-care application with high sensitivity and accuracy. However, direct amplification without DNA purification is excluded and may lead to poor performance of the approach.
Objective: Human Cytomegalovirus (CMV) is a member of the Herpesviridae family, with the ability to establish a long-lived latent infection. CMV infection causes problems in immunocompromised hosts undergoing organ and stem cell transplantation. The prevalence of CMV in adults varies in different geographic regions. The purpose of this study was to assess the prevalence of CMV in the adult population of Afghanistan, which did not have epidemiologic information for CMV infection. Methods: A total of 500 adults residing in main regional provinces of Afghanistan including Nangarhar, Herat, Mazari Sharif, Kandahar and Kabul in the age range of 25-70 years old were randomly selected to include in the study. Among the participants, 263 (52.6%) were female and 237 (47.4%) were male. The samples were tested for the presence of CMV IgM and IgG antibodies using chemiluminescence immunoassay on the Abbott Architect automated platform. Results: The seropositivity of CMV was found 99.79 % in Afghanistan. There were no significant differences in the prevalence CMV infection among the five regions. The seropositivity anti-CMV IgG positive rate in Kandahar, Kabul, Nangarhar and, Herat was determined as 100%. The CMV IgG prevalence was 98.99% in Mazar-i Sharif. Anti CMV IgM was found 1.24% in Afghanistan. Conclusions: Our study shown that the seroprevalence is high in Afghanistan. Because of the high frequency of seropositivity in general population in Afghanistan, the approaches for preventing CMV reactivation need to be developed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.