Hepatitis B is a disease acquired via sexual contact or needle sharing with an infected person or can be passed from an infected mother to her baby. In the U.S., pregnant mothers who get prenatal care are routinely tested for this disease and only a very small percentage are infected. Nevertheless, the HepB vaccine is routinely given to ALL babies on day of birth, even if the mother is disease-free.
One danger with this vaccine is that it contains aluminum as an adjuvant (see "What's in a Vaccine" for an explanation of adjuvants). Aluminum is a known neuro-toxin for which the FDA has established strict limits. Despite this fact, hospitals administer the full, adult-sized vaccine to new born babies without any adjustment for the baby’s weight. While the aluminum in this vaccine is under the toxic limit for an adult, it is up to 17 times the limit for a baby, depending upon its weight.
Furthermore, the FDA's safety limits of aluminum in vaccine doses have relied solely on dietary exposure studies of adult mice and rats. Having aluminum injected directly into your bloodstream via vaccination is different and potentially more harmful than consuming aluminum so that it passes through your digestive tract.
Vaccine doses do not take into account the recipient's body weight, and the allowed amounts of potentially harmful ingredients, such as aluminum, are calculated based on the average weight of an adult. This could be very dangerous for a child, especially a newborn.