Peter Doshi: Pfizer and Moderna’s “95% effective” vaccines—we need more details and the raw data

January 4, 2021 6park.com
 6park.com
 6park.com
 6park.com
 6park.com
 6park.com

Five weeks ago, when I raised questions about the results of Pfizer’s and Moderna’s covid-19 vaccine trials, all that was in the public domain were the study protocols and a few press releases. Today, two journal publications and around 400 pages of summary data are available in the form of multiple reports presented by and to the FDA prior to the agency’s emergency authorization of each company’s mRNA vaccine. While some of the additional details are reassuring, some are not. Here I outline new concerns about the trustworthiness and meaningfulness of the reported efficacy results.
“Suspected covid-19”
All attention has focused on the dramatic efficacy results: Pfizer reported 170 PCR confirmed covid-19 cases, split 8 to 162 between vaccine and placebo groups. But these numbers were dwarfed by a category of disease called “suspected covid-19”—those with symptomatic covid-19 that were not PCR confirmed. According to FDA’s report on Pfizer’s vaccine, there were “3410 total cases of suspected, but unconfirmed covid-19 in the overall study population, 1594 occurred in the vaccine group vs. 1816 in the placebo group.”
With 20 times more suspected than confirmed cases, this category of disease cannot be ignored simply because there was no positive PCR test result. Indeed this makes it all the more urgent to understand. A rough estimate of vaccine efficacy against developing covid-19 symptoms, with or without a positive PCR test result, would be a relative risk reduction of 19% (see footnote)—far below the 50% effectiveness threshold for authorization set by regulators. Even after removing cases occurring within 7 days of vaccination (409 on Pfizer’s vaccine vs. 287 on placebo), which should include the majority of symptoms due to short-term vaccine reactogenicity, vaccine efficacy remains low: 29% (see footnote).
If many or most of these suspected cases were in people who had a false negative PCR test result, this would dramatically decrease vaccine efficacy. But considering that influenza-like illnesses have always had myriad causes—rhinoviruses, influenza viruses, other coronaviruses, adenoviruses, respiratory syncytial virus, etc.—some or many of the suspected covid-19 cases may be due to a different causative agent.
But why should etiology matter? If those experiencing “suspected covid-19” had essentially the same clinical course as confirmed covid-19, then “suspected plus confirmed covid-19” may be a more clinically meaningful endpoint than just confirmed covid-19.
However, if confirmed covid-19 is on average more severe than suspected covid-19, we must still keep in mind that at the end of the day, it is not average clinical severity that matters, it’s the incidence of severe disease that affects hospital admissions. With 20 times more suspected covid-19 than confirmed covid-19, and trials not designed to assess whether the vaccines can interrupt viral transmission, an analysis of severe disease irrespective of etiologic agent—namely, rates of hospitalizations, ICU cases, and deaths amongst trial participants—seems warranted, and is the only way to assess the vaccines’ real ability to take the edge off the pandemic.
There is a clear need for data to answer these questions, but Pfizer’s 92-page report didn’t mention the 3410 “suspected covid-19” cases. Nor did its publication in the New England Journal of Medicine. Nor did any of the reports on Moderna’s vaccine. The only source that appears to have reported it is FDA’s review of Pfizer’s vaccine.


贴主:中间派于2021_01_12 2:52:16编辑