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.
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.
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