Now nearly a century old, the Bacillus Calmette-Guérin (BCG) vaccine is used routinely in humans for the prophylaxis of tuberculosis and to clear up leprosy. As the immune response to the vaccine shows some degree of cross-antigenicity, the vaccine also affects a level of resistance to a range of unrelated diseases and pathogens.
Clinical studies data have shown that the BCG vaccine has effects on autoimmune and inflammatory diseases.
Although the vaccine does not possess any inherent antiviral activity, it engages in the host immune system such that many types of viral infections are considerably reduced. Hence, we expect that the frequency and severity of many microbial diseases, including COVID-19, will be lower in counties in which mass BCG vaccination programs are implemented. So the BCG vaccine may prove useful in the coming months especially in countries where already have mass BCG vaccination, as the COVID-19 pandemic has placed an unprecedented strain on health services across the world. Currently, countless front-line healthcare staff is in immediate danger of exposure to the SARS-CoV-2 virus.
Furthermore, as oral zinc sulfate as immunomodulator has proved an effective means to treat various viral diseases (including viral warts and herpes), parasitic infections, and diseases with autoimmune reactions such as Behcet’s disease and recurrent aphthous stomatitis, it could be employed in combination with the BCG vaccine to enhance the immunological functions of patients with COVID-19. So BCG immunotherapy combined with oral zinc sulfate will be encouraging protective programs in societies where coronavirus is going to spread.