The basis of publicity and propaganda is repetition. Any slogan that is repeated infinitely is pure publicity or propaganda.
This video shows some quite old stuff, when it was still mainly the US where people were bombarded with this “Safe & Effective” mantra. However, once confirmed the success at home, unfortunately just like their other junk (drinks, food, entertainment…) the US now even managed to ‘globalize’ junk-medicine using the WHO together this same easy propaganda formula.
It is not surprising, then, to see how a younger version of the key figures in the global Covid hysteria Fauci and Tedros were already engaged in vaccine propaganda years ago.