Infection History Determines Susceptibility to Unrelated Diseases

Toxicology issues related to the COVID–19 outbreak

In viral pandemics, such as coronavirus disease 2019 (COVID–19), the impact of real-life exposures to multiple toxic stressors that increase immune system dysfunction is followed by the main pandemic-associated virus (SARS–CoV–2, for COVID–19) exploiting the dysfunctional immune system to trigger a chain of events ultimately leading to the pandemic (COVID–19). Thus pandemics have two main components: virology (focused on the virus) and toxicology (focused on the toxic stressors).

The present chapter will focus mainly on the immune system toxicology component. It identifies the factors shown most frequently to increase immune system dysfunction, and then addresses vaccine toxicology in detail. The chapter concludes by reviewing two types of treatments: immune-augmenting and immune-strengthening. The immune-augmenting approaches are virology-centric (e.g., quarantine, face masks, repurposed antiviral treatments, vaccines, etc.), and the immune-strengthening approaches are toxicology-centric (e.g., eliminating the factors that contribute to immune system dysfunction, and adding factors that increase immune system health).

BCG vaccine: Worrying proposal for COVID-19

Bacille Calmette-Guérin (BCG) vaccine is proven to be effective in protecting against severe tuberculosis. It has been suggested to be able to exert a non-specific beneficial effect as protection against other infectious diseases. The duration of protection against tuberculosis is estimated to be from 10 to 15 years, but the duration of the protection against other infections is not known, maybe up to 20 years, maybe much shorter than that. We don’t know it for sure. BCG induced trained immunity paradigm is based on experimental models, cohort studies with low number of individuals, and some epidemiological data in which other possible interfering factors are not controlled. The titles and scopes of scientific articles should be cautiously considered as they can promote indications of getting vaccinated or revaccinated with BCG, before its effectiveness is confirmed and recommendations are published. Besides, revaccination with BCG can put at serious risk patients with primary or secondary immunodeficiency. Maybe BCG vaccine is effective in preventing COVID-19 deaths or reducing its severity, but may the effect of this vaccine be relevant even with poor health politics and assistance? It is very difficult to compare the epidemiologic data about COVID-19 in different countries. There are countless factors, mainly social and related to the healthcare system, which can be more decisive than the hypothesis of trained immunity induced by BCG. Until now, we can say that BCG’s protective role is, at least, insufficient, given many other factors that corroborate SARS-CoV-2 infection and/or its severity.

Vaccine- and natural infection-induced mechanisms that could modulate vaccine safety

A degraded/dysfunctional immune system appears to be the main determinant of serious/fatal reaction to viral infection (for COVID-19, SARS, and influenza alike). There are four major approaches being employed or considered presently to augment or strengthen the immune system, in order to reduce adverse effects of viral exposure. The three approaches that are focused mainly on augmenting the immune system are based on the concept that pandemics/outbreaks can be controlled/prevented while maintaining the immune-degrading lifestyles followed by much of the global population. The fourth approach is based on identifying and introducing measures aimed at strengthening the immune system intrinsically in order to minimize future pandemics/outbreaks. Specifically, the four measures are: 1) restricting exposure to virus; 2) providing reactive/tactical treatments to reduce viral load; 3) developing vaccines to prevent, or at least attenuate, the infection; 4) strengthening the immune system intrinsically, by a) identifying those factors that contribute to degrading the immune system, then eliminating/reducing them as comprehensively, thoroughly, and rapidly as possible, and b) replacing the eliminated factors with immune-strengthening factors. This paper focuses on vaccine safety. A future COVID-19 vaccine appears to be the treatment of choice at the national/international level. Vaccine development has been accelerated to achieve this goal in the relatively near-term, and questions have arisen whether vaccine safety has been/is being/will be compromised in pursuit of a shortened vaccine development time. There are myriad mechanisms related to vaccine-induced, and natural infection-induced, infections that could adversely impact vaccine effectiveness and safety. This paper summarizes many of those mechanisms.

[Editorial] COVID‑19: Post‑lockdown guidelines

Since March, 2020, in response to the COVID‑19 pandemic, many countries have been on lockdown (at different levels of severity), restricting many activities and businesses that involve gatherings of large numbers of people in close proximity. Currently (early June, 2020), countries across the globe are in different stages of easing lockdown restrictions. Public policies for behaviors and actions during this transition period vary widely across countries and within country jurisdictions. The present editorial will address potential policies that could minimize resurgence of the present pandemic (the 'second‑wave') and reduce the likelihood and severity of similar future pandemics.