Experience in Studying Herd and Individual Immunity to the SARS-CoV-2 Virus in Medical Workers

The aim was to study SARS-CoV-2 immunity among medical workers in Kazan.Materials and methods. Studied were serum samples from 348 medical workers from 10 medical organizations in Kazan, divided into groups according to the level of the alleged risk of infection of employees. To determine IgG, a two-stage direct version of the solid-phase ELISA and the test-system “SARS-CoV-2-IgG-ELISA-BEST” (Russia) were used.Results and discussion. At the time of the study and over the previous three months, the examined medical workers had no symptoms of acute respiratory viral infection or respiratory tract infections; there were negative results of examining nasopharyngeal/ oropharyngeal swabs for the presence of SARS-CoV-2 RNA. Seroprevalence for IgG to SARS-CoV-2 virus for different medical organizations in Kazan ranged within the scope of 3.3–30.8 % and averaged 16.4 %. The wide variation in seroprevalence values in medical workers of different medical organizations may indicate different levels of intensity of professional contacts and the effectiveness of anti-epidemic measures in these medical organizations. Among medical workers with seropositive results, the prevalence of persons with a very high coefficient of positivity (49.1 %) is observed, which characterizes high level of antiviral antibodies. The presence of a high proportion of seropositive individuals among medical workers, who have had an asymptomatic form of COVID-19 confirms the high intensity of the latent epidemic process, which must be taken into account when organizing preventive measures, including vaccination.

Automated, flow-based chemiluminescence microarray immunoassay for the rapid multiplex detection of IgG antibodies to SARS-CoV-2 in human serum and plasma (CoVRapid CL-MIA)

In the face of the COVID-19 pandemic, the need for rapid serological tests that allow multiplexing emerged, as antibody seropositivity can instruct about individual immunity after an infection with SARS-CoV-2 or after vaccination. As many commercial antibody tests are either time-consuming or tend to produce false negative or false positive results when only one antigen is considered, we developed an automated, flow-based chemiluminescence microarray immunoassay (CL-MIA) that allows for the detection of IgG antibodies to SARS-CoV-2 receptor-binding domain (RBD), spike protein (S1 fragment), and nucleocapsid protein (N) in human serum and plasma in less than 8 min. The CoVRapid CL-MIA was tested with a set of 65 SARS-CoV-2 serology positive or negative samples, resulting in 100% diagnostic specificity and 100% diagnostic sensitivity, thus even outcompeting commercial tests run on the same sample set. Additionally, the prospect of future quantitative assessments (i.e., quantifying the level of antibodies) was demonstrated. Due to the fully automated process, the test can easily be operated in hospitals, medical practices, or vaccination centers, offering a valuable tool for COVID-19 serosurveillance.

Trajectory of individual immunity and vaccination required for SARS-CoV-2 community immunity: a conceptual investigation

SARS-CoV-2 is an international public health emergency; high transmissibility and morbidity and mortality can result in the virus overwhelming health systems. Combinations of social distancing, and test, trace, and isolate strategies can reduce the number of new infections per infected individual below 1, thus driving declines in case numbers, but may be both challenging and costly. These interventions must also be maintained until development and (now likely) mass deployment of a vaccine (or therapeutics), since otherwise, many susceptible individuals are still at risk of infection. We use a simple analytical model to explore how low levels of infection, combined with vaccination, determine the trajectory to community immunity. Understanding the repercussions of the biological characteristics of the viral life cycle in this scenario is of considerable importance. We provide a simple description of this process by modelling the scenario where the effective reproduction number R eff is maintained at 1. Since the additional complexity imposed by the strength and duration of transmission-blocking immunity is not yet clear, we use our framework to probe the impact of these uncertainties. Through intuitive analytical relations, we explore how the necessary magnitude of vaccination rates and mitigation efforts depends crucially on the durations of natural and vaccinal immunity. We also show that our framework can encompass seasonality or preexisting immunity due to epidemic dynamics prior to strong mitigation measures. Taken together, our simple conceptual model illustrates the importance of individual and vaccinal immunity for community immunity, and that the quantification of individuals immunized against SARS-CoV-2 is paramount.

Covid-19 Vaccination Options for Immunosuppressed Cancer Patients

Background: Currently, many COVID-19 vaccine candidates are being developed to end the pandemic; however, immunosuppressed cancer patients have been excluded from the participating criteria. It is important that they are able to examine their options for achieving immunity against COVID-19. Purpose: This review aims to discuss the available options that can be taken to vaccinate immunosuppressed cancer patients when no vaccine is being developed for their safety. Method: A literature study was conducted using Google Scholar, DOAJ, and GARUDA Library on November 2, 2020, focusing on articles examining vaccination guidelines for immunosuppressed cancer patients. Results: The search found 200 articles, which were curated to obtain 13 articles that satisfied all inclusion criteria. These consist of four guidelines, five reviews, and four research articles. Based on the literature, immunosuppressed cancer patients have the option to use the vaccines currently under development, with precautions set for live attenuated and potentially infectious vaccines. Vaccination timing also needs to be adjusted so as to fall at a certain time before or after the immunosuppressive condition. Moreover, a more complete COVID-19 immunity can be achieved through a synergy between individual vaccination and the construction of herd immunity. Conclusion: Most of the vaccines currently under development may be safe for cancer patients, being mindful of several considerations. Here, herd immunity can serve as a complement to individual immunity.

Herd immunity: In relation to COVID-19

Herd immunity, also known as indirect protection, community immunity, or community protection, refers to the protection of susceptible individuals against an infection when a sufficiently large proportion of immune individuals exist in a population. In other words, herd immunity is the inability of infected individuals to propagate an epidemic outbreak due to lack of contact with sufficient numbers of susceptible individuals. It stems from the individual immunity that may be gained through natural infection or through vaccination. The term herd immunity was initially introduced more than a century ago. In the latter half of the 20th century, the use of the term became more prevalent with the expansion of immunization programs and the need for describing targets for immunization coverage, discussions on disease eradication, and cost-effectiveness analyses of vaccination programs. Eradication of smallpox and sustained reductions in disease incidence in adults and those who are not vaccinated following routine childhood immunization with conjugated Haemophilusinfluenzae type B and pneumococcal vaccines are successful examples of the effects of vaccine-induced herd immunity.

Mosaic vaccination: how distributing different vaccines across a population could improve epidemic control

Although vaccination has been remarkably effective against some pathogens, for others, rapid antigenic evolution implies that vaccination confers only weak and/or short-lived protection. Consequently, considerable effort has been invested in developing more evolutionarily robust vaccines, either by targeting highly conserved components of the pathogen (universal vaccines) or by including multiple immunological targets within a single vaccine (multi-epitope vaccines). An unexplored third possibility is to vaccinate individuals with one of a number of qualitatively different vaccines, creating a ‘mosaic’ of individual immunity in the population. Here we explore whether? a mosaic vaccination strategy can deliver superior epidemiological outcomes to ‘conventional’ vaccination, in which all individuals receive the same vaccine. We suppose vac-cine doses can be distributed both between distinct vaccine ‘targets’ (e.g., different surface proteins against which an immune response can be generated) and across immunologically-distinct variants at these targets (e.g., strains); the pathogen can undergo antigenic evolution at both targets. Using simple mathematical models, we show that conventional vaccination is often outperformed by mosaic vaccination strategies, that is, mosaic vaccination often leads to fewer infected individuals over the course of the epidemic.

How to Determine When SARS-CoV-2 Antibody Testing Is or Is Not Useful for Population Screening: A Tutorial

Extensive testing lies at the heart of any strategy to effectively combat the SARS-COV-2 pandemic. In recent months, the use of enzyme-linked immunosorbent assay–based antibody tests has gained a lot of attention. These tests can potentially be used to assess SARS-COV-2 immunity status in individuals (e.g., essential health care personnel). They can also be used as a screening tool to identify people that had COVID-19 asymptomatically, thus getting a better estimate of the true spread of the disease, gain important insights on disease severity, and to better evaluate the effectiveness of policy measures implemented to combat the pandemic. But the usefulness of these tests depends not only on the quality of the test but also, critically, on how far disease has already spread in the population. For example, when only very few people in a population are infected, a positive test result has a high chance of being a false positive. As a consequence, the spread of the disease in a population as well as individuals’ immunity status may be systematically misinterpreted. SARS-COV-2 infection rates vary greatly across both time and space. In many places, the infection rates are very low but can quickly skyrocket when the virus spreads unchecked. Here, we present two tools, natural frequency trees and positive and negative predictive value graphs, that allow one to assess the usefulness of antibody testing for a specific context at a glance. These tools should be used to support individual doctor-patient consultation for assessing individual immunity status as well as to inform policy discussions on testing initiatives.

INFLUENCE OF IMIDACLOPRIDE ON THE IMMUNITY OF HONEY BEES (APIS MELLIFERA L.)

The effect of the neonicotinoid, which is the most toxic for bees, on the components of the individual immunity of Apis mellifera L. workers, was studied. It was shown that a non-lethal dose of imidacloprid caused pathological changes in the intestine and fat body cells, the insect's reaction to its own decaying cells and tissues, aggregation, adhesion and lysis of granulocytes that removes a significant proportion of protective cells from the bloodstream, the generation of reactive oxygen species under the inhibition of phenol oxidase activity in hemocytes.

Cutaneous Tuberculosis- probably due to mycobacterium bovis infection: A case report

Cutaneous tuberculosis is an infection caused by M. tuberculosis complex, M. bovis and bacillus Calmette- Guérin. Depending on individual immunity, environmental factors and the type of inoculum, it may present varied clinical and evolutionary aspects. Here we found a similar case where a 63 year old female patient developed cutaneous tuberculosis either due to direct inoculation or secondary to consumption of unpasteurized milk. The wound was not healing even after several courses of antibiotics and started healing only after starting anti-tubercular treatment. Hence we recommend that clinicians should keep this possibility in mind for early diagnosis and prompt treatment.