A Parent's Guide to Vaccines

Knowing which shots kids need and when can be confusing. Our expert clears it up.

The tears and screaming, as upsetting as they are, are well worth the effort. A simple prick of the skin provides children with lifetime protection against diseases like chickenpox, meningitis, and hepatitis. With a schedule starting at birth and lasting into childhood, millions of kids in the United States are vaccinated each year, usually before school begins in the fall. Mary Glodé, MD, a professor of pediatrics and chief of the infectious diseases section at the University of Colorado School of Medicine and Children's Hospital Colorado, explains which vaccines kids should be getting and when -- starting with the first shot babies receive only hours after birth.

Hepatitis B

When: The hepatitis B vaccine is a three-dose series. Before newborns leave the hospital, they are given a shot in case their mothers have the disease, which can be transmitted to a child during birth, says Glodé. Second and third doses are usually given one month and six months later. Immunity lasts for more than 20 years.

Why: Hep B is a virus that can damage the liver, causing infection and scarring, and increasing cancer risk. Kids with hep B are at high risk of becoming seriously sick -- about 90% of infected infants eventually develop lifelong infection, and 25% die from liver disease. 

Rotavirus

When: There are two brands of the rotavirus vaccine, one that requires two doses and one that requires three -- at ages 2 months, 4 months, and 6 months, if necessary. All are given as a liquid by mouth.

Why: Rotavirus is the No. 1 cause of vomiting and diarrhea among children worldwide. The virus can also cause fever, loss of appetite, and dehydration.

The vaccine does its job well. Studies show that during a baby's first year, the vaccine prevents more than 85% of severe rotavirus infections and more than 75% of all rotavirus infections.

Diphtheria-Tetanus-Pertussis (DTaP)

When: "This was the first combination vaccine made," says Glodé. "The purpose was to simply minimize the number of times a pediatrician needs to poke a child." DTaP follows a five-dose schedule: at 2, 4, 6, and 15 to 18 months, and then again between 4 and 6 years of age. Immunity lasts at least 10 years.

Why: This one shot protects against three dangerous diseases. Diphtheria is a respiratory disease that can lead to breathing problems and, potentially, paralysis, heart failure, and death. Tetanus is a bacterial infection that can cause muscle spasms that tear muscle tissues or fracture the spine. Pertussis, known as whooping cough, is a highly contagious respiratory infection that causes coughing so powerful and prolonged that a child may stop breathing during an episode.

Haemophilus Influenzae Type B

When: The haemophilus influenzae type b bacteria (known as Hib) vaccine is given at 2 and 4 months of age, and again at 6 months if a third dose is necessary. (This depends on the brand of vaccine used.) The final dose is given at 12 to 15 months and protects a child until his own immunity kicks in several years later.