It is an absolute fact that all the runners who participated in the Brooklyn Half Marathon on Saturday declared that they had been vaccinated for Covid-19. Whether or not that is relevant to the unprecedented number of runners who collapsed or even the man who died during the event is another story. Saturday’s running conditions were unusually hot and humid, even at 9 a.m. when the participant David Reichman is reported to have died shortly after collapsing after the finish line. The New York Post reported that Reichman, a 32 year-old man, collapsed “after suffering from possible cardiac arrest, according...