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That's not the case. Even against Delta effectiveness dropped very rapidly and then actually went negative. The UK is one of the few countries that kept regularly publishing case stats even after this happened and it showed that once the initial vaccine 'high' wore off, vaccinated people were getting infected more frequently than the unvaccinated. Omicron didn't change this.

This sort of thing is unintuitive but has happened before. In fact Fauci cited the possibility of this effect as one of the reasons not to rush the trials. Unfortunately the trials did not detect this, probably due to bad use of statistics (the way they classify people as unvaccinated for weeks after having actually been given the shot can warp the stats).

[DiogenesKynikos]

> Even against Delta effectiveness dropped very rapidly and then actually went negative.

Effectiveness against Delta did not go negative. Protection against infection decreased, but was still quite significant. A single booster also greatly increased protection against Delta, which is why many countries initiated booster campaigns in the Fall of 2021.

> Unfortunately the trials did not detect this, probably due to bad use of statistics

The trials were always designed to test protection against symptomatic disease, severe cases and death. They were not designed to test protection against infection. Everyone who read the trial registrations and the studies knew this from the beginning. The fact that this has recently been presented as a big revelation in the media just shows how uninformed the public (and much of the media) is. It's also a reflection of the revisionist narrative (i.e., we shouldn't have done anything about CoVID) taking hold.

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Protection was falling steadily at the time delta disappeared completely, and continued falling on the same trend far below zero.

Your description of the trials is perfectly inverted! I wonder how that happens. The trials weren't designed to detect anything except reduced PCR test positivity i.e. infections. They didn't attempt to determine what a "severe case" was because that distinction was invented only after the falling effectiveness made it necessary to do so, and as for death, more people died in the vaccine arm than the placebo arm! They definitely didn't make claims about reducing the death rate because it was so tiny to begin with that they couldn't get a big enough sample of COVID deaths to make any conclusions, not even with 64,000 odd people.

[DiogenesKynikos]

> The trials weren't designed to detect anything except reduced PCR test positivity i.e. infections.

> They didn't attempt to determine what a "severe case" was because that distinction was invented only after the falling effectiveness made it necessary to do so

I'm sorry, but you're wrong on both of these points. From the Moderna phase-3 trial description [0] on clinicaltrials.gov:

> Primary Outcome Measures:

> 1. Efficacy: Number of Participants with a First Occurrence of COVID-19 Starting 14 Days after Second Dose of mRNA-1273

If you look at the trial protocol, there is no regular PCR testing (except for at the start of the trial and at administration of the 2nd dose). Only people who have two or more symptoms are tested. This means that the trial is only meant to test efficacy against symptomatic infection (also known as "CoVID-19," the disease, as opposed to the virus, "SARS-CoV-2"). From the scientific paper[1] on Moderna's phase-3 results:

> Covid-19 cases were defined as occurring in participants who had at least two of the following symptoms: fever (temperature ≥38°C), chills, myalgia, headache, sore throat, or new olfactory or taste disorder, or as occurring in those who had at least one respiratory sign or symptom (including cough, shortness of breath, or clinical or radiographic evidence of pneumonia) and at least one nasopharyngeal swab, nasal swab, or saliva sample (or respiratory sample, if the participant was hospitalized) that was positive for SARS-CoV-2 by reverse-transcriptase–polymerase-chain-reaction (RT-PCR) test.

Then, later on from clinicaltrials.gov:

> Secondary Outcome Measures:

> 1. Number of Participants with a First Occurrence of Severe COVID-19 Starting 14 Days after Second Dose of mRNA-1273 or Placebo

So you see that the idea of preventing "severe CoVID-19" goes back all the way to the formulation of the trials in early 2020.

And more detail from the scientific paper:

> A secondary end point was the efficacy of mRNA-1273 in the prevention of severe Covid-19 as defined by one of the following criteria: respiratory rate of 30 or more breaths per minute; heart rate at or exceeding 125 beats per minute; oxygen saturation at 93% or less while the participant was breathing ambient air at sea level or a ratio of the partial pressure of oxygen to the fraction of inspired oxygen below 300 mm Hg; respiratory failure; acute respiratory distress syndrome; evidence of shock (systolic blood pressure <90 mm Hg, diastolic blood pressure <60 mm Hg, or a need for vasopressors); clinically significant acute renal, hepatic, or neurologic dysfunction; admission to an intensive care unit; or death.

0. https://clinicaltrials.gov/ct2/show/NCT04470427

1. https://doi.org/10.1056/NEJMoa2035389