It wasn’t that long ago that many Americans rejoiced at the news that several vaccines against the SARS-CoV-2 virus had been developed and approved for use on an emergency basis. And while there are data showing that the vaccines do, in fact, do a good (if imperfect) job at protecting the inoculated, it now appears that at least one of them wanes 6 months after administration. A preprint report of a study published online by medRxiv notes that protection afforded by the Pfizer vaccine may lag after 6 months. Based on an international study that included nearly 45,000 subjects, researchers concluded that overall effectiveness of the Pfizer vaccine dropped from 96% to 84% over that span. It also reveals, however, that a third booster dose bolsters protection against the Delta variant, especially in subjects between 65 and 85 years of age. Again, the findings have yet to be published in a peer-reviewed journal but were included in Pfizer’s second quarter 2021 earnings report. Addition of a dose 6 months after receiving the first two doses would require further evaluation and authorization by the Food and Drug Administration. In addition, it should be noted that the World Health Organization recommended a moratorium on COVID-19 booster shots until at least 10% of the world’s population has received the first one- or two-dose regimen of the vaccine.

The COVID-19 Vaccines All Seem to Be Working—in the Short Term, Anyway