VACCINE: PRAYER AND WAR

摘要

Everyone is praying now for a vaccine to end this Covid-19 pandemic. Scientists around the world are desperately trying to find a vaccine, drug or therapy to save people from the threat of this killer virus. As of August 21, 231 vaccine candidates are in the fray. Out of these only 24 candidates are supposed to be undergoing clinical trials, of which 6 are now at the beginning of phase Ⅲ and 18 in phase Ⅰ and Ⅱ. None of the candidates has undergone a complete clinical trial so far in order to prove its efficacy. In fact, we don't even know whether any of these endeavours will ultimately succeed in producing a safe and effective vaccine. Biology is a complex subject to me, more complicated than natural sciences like physics or mathematics. This is because the immune system of humans, that resists and destroys pathogens (virus, bacteria, fungus etc.) from entering the human body, is very complex comprising several cooperative phenomena (akin to many-body problems in physics). Equally complex is the way the present virus of Covid-19 operates in the body. Conservatively speaking, the probability of success for a vaccine in the preclinical phase is only around 7%, rising to 15-20% for vaccines that reach the clinical tests. Thus, it is not a matter of surprise that most of the vaccine candidates fail to succeed.