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. So, roughly 150 out 21,750 participants (less than 0.7 percent) became PCR positive in the control group and about one-tenth that number in the vaccine group became PCR positive. The Moderna trial had 30,000 participants. There were 95 “cases” in the 15,000 control participants (about 0.6 percent) and 5 “cases” in the 15,000 vaccine participants (about one-twentieth of 0.6 percent). The “efficacy” figures quoted in these announcements are odds ratios.
There is no evidence, yet, that the vaccine prevented any hospitalizations or any deaths. The Moderna announcement claimed that eleven cases in the control group were “severe” disease, but “severe” was not defined. If there were any hospitalizations or deaths in either group, the public has not been told. When the risks of an event are small, odds ratios can be misleading about absolute risk. A more meaningful measure of efficacy would be the number to vaccinate to prevent one hospitalization or one death. Those numbers are not available. An estimate of the number to treat from the Moderna trial to prevent a single “case” would be fifteen thousand vaccinations to prevent ninety “cases” or 167 vaccinations per “case” prevented which does not sound nearly as good as 94.5 percent effective. The publicists working for pharmaceutical companies are very smart people. If there were a reduction in mortality from these vaccines, that information would be in the first paragraph of the announcement.