It’s Not News, Nor ‘Scandalous,’ That Pfizer Trial Didn’t Test Transmission

The authorized or approved vaccines were initially tested in animals and early phase clinical trials, in which scientists evaluated different doses, checked for the expected immune responses and monitored for potential safety issues. To find out whether the shots prevent disease and are safe, the vaccines that passed the first set of tests were then evaluated in phase 3 trials.

The Moderna and Novavax phase 3 trials each included about 30,000 volunteers, while the Pfizer/BioNTech and Johnson & Johnson trials included about 44,000 each. In each of these trials, half of the participants received a placebo, while the other half received the vaccine, and the volunteers were followed over time to see if they fell ill with COVID-19 and had any adverse reactions.  

The trials were overseen by independent data and safety monitoring boards, and the results were reviewed not only by the Food and Drug Administration, which made the decision to authorize the vaccines for emergency use, but