Covid-19 death MESHD has a different relationship with age TRANS than is the case for other severe respiratory pathogens. The Covid-19 death MESHD rate increases exponentially with age TRANS, and the main risk factors are age TRANS itself, as well as having underlying conditions such as hypertension MESHD hypertension HP, diabetes, cardiovascular disease MESHD, severe chronic respiratory disease MESHD and cancer. Furthermore, the almost complete lack of deaths MESHD in children TRANS suggests that infection MESHD alone is not sufficient to cause death MESHD; rather, one must have gone through a number of changes, either as a result of undefined aspects of aging, or as a result of chronic disease MESHD. These characteristics of Covid-19 death MESHD are consistent with the multistep model of disease MESHD, a model which has primarily been used for cancer, and more recently for amyotrophic lateral sclerosis MESHD amyotrophic lateral sclerosis HP (ALS). We applied the multi-step model to data on Covid-19 case fatality rates (CFRs) from China, South Korea, Italy, Spain and Japan. In all countries we found that a plot of ln (CFR) against ln ( age TRANS) was approximately linear with a slope of about 5. As a comparison, we also conducted similar analyses for selected other respiratory diseases MESHD. SARS showed a similar log-log age TRANS-pattern to that of Covid-19, albeit with a lower slope, whereas seasonal and pandemic influenza showed quite different age TRANS-patterns. Thus, death MESHD from Covid-19 and SARS appears to follow a distinct age TRANS-pattern, consistent with a multistep model of disease MESHD that in the case of Covid-19 is probably defined by comorbidities and age TRANS producing immune-related susceptibility. Identification of these steps would be potentially important for prevention and therapy for SARS-COV-2 infection MESHD.