Title: Researchers Argue Overestimated Efficacy Claims of Pfizer’s COVID-19 Booster Shot
Researchers from Stanford School of Medicine have raised concerns about the exaggerated efficacy claims surrounding Pfizer’s COVID-19 booster shot. In a letter published in the New England Journal of Medicine (NEJM), the team suggests that a 2021 Israeli study on the booster may have overestimated its effectiveness by failing to consider underlying health conditions among participants.
The group examined mortality rates attributed to COVID-19 in the study and subsequent statements by the same authors. By estimating mortality unrelated to the virus based on vaccination status, the researchers found that the boosted group had a significantly lower mortality rate for non-COVID-19 causes compared to the non-boosted group. They also observed a lower incidence of adverse health outcomes in the boosted group.
The authors argue that an individual’s overall health significantly impacts COVID-19-related mortality. If the boosted group had fewer underlying health conditions not accounted for in the data, it would be inaccurate to attribute the lower mortality solely to the third dose of Pfizer’s vaccine.
Epidemiologist Dr. Tracy Høeg, physician-scientist Dr. Vinay Prasad, and Dr. Ram Duriseti highlighted the presence of healthy vaccinee bias in the Israeli study, which they believe may explain the reported benefits of the booster. They are requesting that the study be retracted and are calling for randomized controlled trials to provide more accurate data.
Dr. Joseph A. Ladapo, Florida’s Surgeon General, has endorsed the concerns raised by the letter’s authors, stating that the reported 90 percent benefit of boosters in the NEJM study was solely due to selection bias. Dr. Ladapo also emphasizes the need for randomized controlled trials.
Despite pointing out a lack of transparency from Israel in sharing their data, the authors suggest that healthy vaccinee bias may have influenced overestimations of vaccine effectiveness in other studies as well.
The NEJM study, published on December 23, 2021, examined whether a third dose of Pfizer’s vaccine effectively reduced COVID-19 mortality. The Israeli Ministry of Health had already approved booster doses by July 30, 2021, although evidence of the additional dose’s impact on mortality was limited.
Researchers analyzed data from Clalit Health Services, studying 843,208 individuals over 50 years of age who had received two doses of the Pfizer vaccine at least five months prior. The study compared COVID-19 mortality rates between participants who received a booster during the 54-day study period and those who did not.
Initially, the study reported 65 COVID-19 deaths in the boosted group compared to 137 deaths in the non-boosted group. However, in response to another letter published in February 2022, the study’s authors provided additional information. They clarified that 506 deaths occurred in the boosted group during the study period, of which 441 were unrelated to COVID-19, and 65 were due to the virus. In the non-boosted group, there were 1,100 deaths, with 963 being COVID-19-related and 137 unrelated. The authors acknowledged the need for caution in interpreting deaths unrelated to COVID-19, as they were not adjusted for various factors affecting all-cause mortality.
Dr. Vinay Prasad affirmed that their analysis demonstrated the distorted results of the Israeli studies and concluded that boosters could not have reduced non-COVID-19 deaths.
The issue polarizes experts and highlights the need for further research and clarity.
