Pandemic Covid-19 pneumonia, of SARS-CoV-2 aetiology, is of global importance to health systems, national economies, and individual civil liberties. Multiple therapeutic and prophylactic agents are currently undergoing clinical trial and, while progress towards a curative agent is promising, the principal limiting factor in public health emergency is time. A pre-existing licensed therapeutic would offer reprieve to international citizens currently enduring the adverse consequences of lockdown policies. The current review advances the author's original hypothesis and advocates direct testing of the hypothesis by urinalysis of light-protected samples from critical Covid-19 patients to check for elevated aminolevulinic acid and porphobilinogen.