When will we get a Covid-19 vaccine?
As the lockdown reaches the 6 month point, people everywhere are clinging to the hope that there’ll soon be a coronavirus vaccine so life can return to normal. That aspiration suffered something of a setback last week when the pharmaceutical company AstraZeneca announced the suspension of its “phase 3” trial of the Covid-19 vaccine it’s developing with Oxford University. This was in response to a volunteer in the trial developing an inflammatory condition of the nervous system called transverse myelitis. The trial has since resumed, but has this helped, or damaged, the public perception of vaccine safety? So how are decisions to start and stop clinical trials made, and what does the present trajectory mean for when we’re going to get a coronavirus vaccine? Chris Smith asked vaccinologist Gordon Dougan, who’s overseen the development of many vaccines during his career, to explain…
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Dear dr. SMITH, I really
Dear dr. SMITH, I really deeply appreciate your knowledge and your will to share it with us so I deeply believe that you are right person to answer this question. I would really, really like if you could explain 1. Why is double blind placebo studie so highly rated? 2.what is ALWAYS used as placebo? 3. Why is now, in vaccine testing, as placebo instead of real placebo used other vaccines that also by default has some side effects? So basically comparing two things that both have side effects, you will get smaller differences and automatically it will look less bad. I really stay open for explanation. Thank you for sharing your knowledge
If a trial is double blind,
If a trial is double blind, neither the appraiser or the treatment recipient know what is being given; therefore the risk of bias in observations is minimised.
Placebo is not always used. On some occasions it would be unethical to give a placebo (for instance in a cancer trial) so the current gold standard threapy might be compared against the new intervention. This might lead to a smaller difference in the effect of the intervention, but the trial is powered accordingly to make sure that it can detect such a difference, statistically.
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