Reply To: SARS cov2 and Covid 19

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With respect Clark, I think there are important aspects to the vaccine trials that require scrutiny. They have shown they can reduce covid-19 cases but not that they can prevent hospital admissions, severe disease, deaths, infection or even transmission of the virus. You have often pointed to Goldacre’s “Bad Pharma” for a good insight into how Big Pharma massage statistics to sex up their presentations. Absolute risk reduction is an important metric by which to judge some clinical trials data and in this case we are talking about smallish numbers of end points in large numbers in each arm. 119 people need to be vaccinated to prevent one new covid 19 case. (from ARR 0.84%. number needed to treat is it’s inverse). Nor have they shown how long any effect may last for although I realise the time factor is a constraint.

“Hospital admissions and deaths from covid-19 are simply too uncommon in the population being studied for an effective vaccine to demonstrate statistically significant differences in a trial of 30 000 people. The same is true of its ability to save lives or prevent transmission: the trials are not designed to find out.”

Tal Zaks, chief medical officer at Moderna, told The BMJ that the company’s trial lacks adequate statistical power to assess those outcomes. “The trial is precluded from judging [hospital admissions], based on what is a reasonable size and duration to serve the public good here,” he said.