“…it is notable that evidence of waning immunity was already visible in the data by the 13 March 2021 data cut-off.
“From its peak post-dose 2,” the study authors write, “observed VE [vaccine efficacy] declined.” From 96% to 90% (from two months to <4 months), then to 84% (95% CI 75 to 90) “from four months to the data cut-off,” which, by my calculation (see footnote at the end of the piece), was about one month later.”
Despite the reference to “six month safety and efficacy” in the preprint’s title, the paper only reports on vaccine efficacy “up to six months,” but not from six months. This is not semantics, as it turns out only 7% of trial participants actually reached six months of blinded follow-up (“8% of BNT162b2 recipients and 6% of placebo recipients had ≥6 months follow-up post-dose 2.”) So despite this preprint appearing a year after the trial began, it provides no data on vaccine efficacy past six months, which is the period Israel says vaccine efficacy has dropped to 39%.
Until new clinical trials demonstrate that boosters increase efficacy above 50%, without increasing serious adverse events, it is unclear whether the 2-dose series would even meet the FDA’s approval standard at six or nine months.”
The Emergency Use Authorization requires at least 50% efficacy.
The UCL Virus Watch study found that antibodies generated by two doses of the Oxford/AstraZeneca and Pfizer/BioNTech vaccines started to wane as early as six weeks after the second shot, in some cases falling more than 50% over 10 weeks.The Guardian – UK scientists back Covid boosters as study finds post-jab falls in antibodies
“But here we are, with FDA reportedly on the verge of granting a marketing license 13 months into the still ongoing, two year pivotal trial, with no reported data past 13 March 2021, unclear efficacy after six months due to unblinding, evidence of waning protection irrespective of the Delta variant, and limited reporting of safety data.”
Read the full article by Peter Doshi at the BMJ.