Why is there a standard dose for all infants for vaccinations? Most medications use weight as a guide for amount being administered. Could a 5-pound baby really be the same as a 10-pound baby?
The dose for vaccination was determined by studies, first in animals and then in people. Small amounts of vaccine are used to protect children. These have been shown to be safe and effective in preterm and low birth weight babies and in teenagers, who are obviously much larger.
Although the patients aren’t the same, the immune system response is similar. For most vaccines, it is one size fits all! Of course, there are exceptions. For example, the dose of hepatitis B vaccine for adults is higher than that used in infants. Sometimes the number of doses is different depending on the age of the patient. Children younger than 9 years receive 2 doses of influenza vaccine. People 13 years and older get 2 doses of chickenpox vaccine.