Vaccine makers rarely use inert placebos (such as a saline shot), which is the gold standard for drug trials. Instead, they typically assess the safety of a new vaccine against another vaccine. This hides side effects, as most vaccines have side effects and risks. The Oxford/AstraZeneca COVID-19 vaccine is being tested against a meningitis vaccine, which shares many of the side effects reported from COVID-19 vaccines. Pfizer and Moderna have started offering placebo recipients in their trials the real mRNA gene therapy, which means it will be even more difficult to tease out which side effects are actually caused by the shot and which ones aren’t, over the long term. In one clinical trial for the Moderna vaccine in Lenexa, Kansas, virtually all of the 650 volunteers who initially received the placebo have opted to get the real vaccine, which means there’s essentially no comparison group left for the ongoing study, which was slated to run for two years. Some argue that placebo arms aren’t needed in COVID-19 vaccine trials, but their argument hinges on the idea that the vaccine being tested is known to be safe, which it absolutely is not at this point, and won’t be for many years. https://articles.mercola.com/sites/articles/archive/2021/03/02/covid-vaccine-testing.aspx
