by Gilbert Berdine, MD
Mises.org
Pfizer recently announced that its covid vaccine was more than 90 percent “effective” at preventing covid-19. Shortly after this announcement, Moderna announced that its covid vaccine was 94.5 percent “effective” at preventing covid-19. Unlike the flu vaccine, which is one shot, both covid vaccines require two shots given three to four weeks apart. Hidden toward the end of both announcements, were the definitions of “effective.”
Both trials have a treatment group that received the vaccine and a control group that did not. All the trial subjects were covid negative prior to the start of the trial. The analysis for both trials was performed when a target number of “cases” were reached. “Cases” were defined by positive polymerase chain reaction (PCR) testing. There was no information about the cycle number for the PCR tests. There was no information about whether the “cases” had symptoms or not. There was no information about hospitalizations or deaths. The Pfizer study had 43,538 participants and was analyzed after 164 cases.