Haemophilus influenzae type b (Hib).

Not to be confused with the "flu" influenza, the Hib bacterium causes potentially deadly meningitis, pneumonia and bacterial sepsis. Because of widespread use of the vaccine since the early 1990s, Hib has been nearly eliminated in the United States. The key to providing optimal protection is to make sure children are vaccinated as early as possible within the acceptable vaccination timeframe.

Hepatitis B.

Hepatitis B can lead to acute and chronic liver disease as well as liver cancer. There has been some controversy about giving the vaccine to children, mostly because of the myth that the disease is transmitted only by sexual contact or needle exchange. In fact, the disease can be spread through routine close contact with people living in the same household, and studies from other countries suggest that normal child-to-child play can spread infection.

All children and adolescents should be immunized. Although rumors suggest that the vaccine may cause chronic illness, including multiple sclerosis or other demyelinating diseases, scientific studies have shown no such association.