What is particularly interesting is the response in the elderly population, as it's this group that seem most at-risk. The earlier studies were done in a younger population without co-morbidities, but later studies included all-comers. The pfizer study included older patients, though not many by the looks of it. They allowed for those with chronic conditions, though not if they were immunocompromised as a result of it. 9% black/african-american and 28% hispanic.