Nearly every parent has had questions about vaccines - including their necessity or the vaccination timeline.
Recent advancements in the pediatric field have made the vaccination process more efficient, experts say. Other vaccines are continually evolving, while physicians worry that the vaccinations that have been around for several decades are losing their importance factor among parents.
Although combination vaccines have been used for decades, there are several more available to pediatricians today.
"There are a lot more combination vaccines now, so it cuts down on the amount of shots babies have to get," said Dr. Mark Kinne, a pediatrician with Franciscan Hammond Clinic in St. John.
The chicken pox and MMR (measles, mumps and rubella) vaccine are now given together at age 1 and again at age 5, he said.
There's also a combination DPT (diphtheria, pertussis and tetanus) and polio vaccine. One, called Pentacel, adds in Hemophilus influenza, while another called Pediarix adds in Hepatitis B.
"These combination vaccines are particularly helpful to catch up children who have gotten behind schedule with their immunizations," said Dr. Charlene Graves, chairman of the Immunization Committee at the Indiana Chapter of the American Academy of Pediatrics.
Although an HPV vaccine has been available for nearly three years for teenage girls and young women, physicians now recommend giving the vaccination to boys as well.
Human papillomavirus is the most common sexually transmitted virus in the United States, with more than half of sexually active men and women infected at some point in their lives, according to the Centers for Disease Control.
Most HPV infections don't cause symptoms and go away on their own, but the virus can cause cervical cancer in women - the second leading cause of cancer deaths among women around the world.
"In boys, it reduces the chance for penile cancer," said Dr. Geraldine Feria, a member of the Porter Physician Group of Porter Regional Hospital.
The vaccine also can prevent genital warts and anal cancer in both males and females, Kinne said.
Doctors recommend vaccinating both girls and boys at 11 or 12 years of age, though it may be given starting at age 9.
"The biggest reason for boys to get it is it's a sexually transmitted disease, so it cuts down on the spread of the virus," Kinne said.
Feria said some parents have the misguided notion that vaccinating their children against HPV might promote promiscuity in kids.
"Truth be told, they're right that they're not at risk until they do become sexually active," she said. "I explain it to the parents that when that becomes the possibility, the sooner we give it, the better so we don't miss it."
While Indiana has not seen a large increase in reported cases of pertussis, or whooping cough, for the United States as a whole, in 2012 more than 48,000 cases were reported to the CDC - the largest number in several years, Graves said.
"There are many more cases of whooping cough that are not recognized or reported, estimated at more than 1 million cases," she said.
For protection against whooping cough, children and adults must receive the pertussis vaccine, also known as Tdap, which combines tetanus, diphtheria and pertussis.
"This is a one-time shot that replaces the tetanus booster shot needed by adults every 10 years," Graves said.
This is especially important for anyone who has contact with infants, Kinne said.
Pertussis is very contagious, he said, and most severely affects children younger than 1.
"A baby doesn't get the vaccine until 2 months of age, so in those first few months, they're pretty vulnerable," he said.
In fact, about half of infants younger than 1 who get the disease need treatment in the hospital. Pertussis can be deadly for one or two infants per 100 who are hospitalized, according to the CDC.
"We used to think the (pertussis) vaccine gave you lifetime immunity, and it does not," Kinne said. "Those considering having a family should consider making sure their whooping cough is up to date."
A new recommendation is that all pregnant women are now urged to get Tdap vaccine in the third trimester of pregnancy, and to get the Tdap shot again during each repeat pregnancy, Graves said.
"Despite the fact that Tdap vaccines have been available since 2005, as of 2011, less than 15 percent of adults have received a Tdap vaccination," she said.
The debate over whether certain vaccines lead to autism in children still rages on. The controversy began about 15 years ago when Andrew Wakefield published a paper in 1998 called "The Lancet."
Since then, however, the study has been retracted and scientists have not been able to find a link between autism and childhood vaccinations - mainly the MMR vaccine.
"It's very sad and very unfortunate when they came out prematurely with autism being linked to MMR," Feria said.
Although some of her patients are still reluctant to immunize their children, she works with them to find a vaccination schedule that works for their family.
"If someone refuses Hepatitis A vaccine, I'm going to say that's fine as long as you don't go to a third world country," she said. "But with MMR, you can die from complications from measles.
"I'm from the Philippines, and in my country, we still have very high mortality from measles because not everyone can afford it," she said. "In this country where anyone can get an MMR, there's no reason why everyone isn't vaccinated."