Infectious diseases have become a major concern in every part of the world for a long time. Infectious diseases create harm and significant disadvantages for a specific place or country. Vaccines are designed to induce the human immune system against parasites that cause infectious diseases. Recognizing the mechanism of vaccines to create a robust immune system, I disagree that vaccines are not necessary and dangerous. First, the purposes and effects of vaccines can be linked by people living in certain countries or places. People with immunodeficiency conditions, followed by older people, are the most sensitive groups to be infected. Vaccines are essential as they can create herd immunity, a system where children, teenagers, and stronger people are given vaccine shots. Soon they will develop stronger immune systems against certain parasites that could protect the weaker ones. Secondly, vaccines could induce the human immune system by an active mechanism, which may cause adverse eff...