The placebo effect will have to be taken into account in the development of vaccines and treatments, according to this opinion in Stat News.

“The placebo response is a complex psychobiological phenomenon that describes the clinical improvement seen in patients taking dummy or sham medicines. It can also comprise some proportion of the measured effect among patients receiving active drugs. Multiple behavioral, psychophysiological, and neuroimaging studies have shown that the placebo response is a real, multifactorial effect associated with changes in biochemical pathways in the brain. The effect is patient specific and is influenced by patient expectations and certain well-defined personality traits.

While drug developers are attuned to considering the placebo response in areas like pain and depression, it may not be immediately apparent why it is so critical for the development of Covid-19 therapies and vaccines. What set the stage was the FDA’s regulatory guidance, released in May, directing how the biopharma industry should evaluate drugs and vaccines being developed to fight the pandemic.”