re: Are y'all going to get the vaccine?

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Pfizer and Moderna were more effective than J&J in the trials.

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But comparing the efficacy of those vaccines to the efficacy of Johnson & Johnson’s is challenging because of differences in the designs of the Phase 3 clinical tests — essentially the trials were testing for different outcomes. Pfizer’s and Moderna’s trials both tested for any symptomatic Covid infection. Pfizer started counting cases from seven days after receipt of the second dose of vaccine, while Moderna waited until day 14 to start counting cases.

J&J, by contrast, sought to determine whether one dose of its vaccine protected against moderate to severe Covid illness — defined as a combination of a positive test and at least one symptom such as shortness of breath, beginning from 14 or 28 days after the single shot. (The company collected data for both.)

Because of the difference in the trials, making direct comparisons is a bit like comparing apples and oranges. Additionally, Pfizer and Moderna’s vaccines were tested before the emergence of troubling new variants in Britain, South Africa, and Brazil. It’s not entirely clear how well they will work against these mutated viruses.

The J&J vaccine was still being tested when the variants were making the rounds. Much of the data generated in the South African arm of the J&J trial involved people who were infected with the variant first seen in South Africa, called B.1.351.

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