Fig. 3.

Severity of the COVID-19 depends on the level of cytokine storm and T cell lymphopenia and both are associated with pulmonary damage, respiratory distress and higher mortality. BCG induces epigenetic and functional reprogramming in human monocytes and increases immunity for un-related viral infections and Interleukin (IL)-1β plays as mediator of trained immunity responses.⁸ Hence, durable epigenetic alterations to increase antiviral function of innate immune cells is observed after live vaccines, facilitating a faster and better responsiveness if exposed to re-infections.^16,29