Early childhood immunization is critical because vaccine-preventable diseases are most likely to strike during early childhood, according to the Mayo Clinic. Early childhood is also the age when such diseases are most likely to cause complications.
The very first exposure to an antigen prompts the immune system to produce antibodies, thus establishing immunity to that antigen, the Centers for Disease Control and Prevention notes. Vaccines contain dead or weakened versions of antigens that are potent enough to trigger the production of antibodies without causing illness. Vaccinating children allows them to build immunity without getting sick, which is safer for them and for the communities they inhabit.
Young children are particularly vulnerable to vaccine-preventable diseases because their immune systems may not have developed the ability to fight full-strength antigens. This is why so many children died from diseases such as measles, polio and whooping cough prior to early childhood immunization, the CDC states.
There are those who cannot get vaccinated; some children are too young for it, and some have medical conditions that don't allow it. People in these situations must rely on the immunity of others to stay well, which is another reason why widespread early childhood vaccination is crucial for community health.