The American participation in the Vietnam War was very different from its involvement in the Bay of Pigs Invasion.
In the Vietnam War, the United States carried out direct participation, with first-hand military planning and execution and large-scale attacks. Some 60,000 Americans died in the conflict, of about one million who participated.
In contrast, in the Bay of Pigs Invasion, American participation was indirect. That is, the attack was planned and the troops trained by American forces, but these were made up of Cuban exiles, not American soldiers. In addition, it was a small-scale attack, both because of the low number of men involved and because of its short duration.