ANN ARBOR, Mich. -

You've checked off the new backpack and a long list of supplies, but is your child still missing something critical for back to school?

Experts are urging parents to check their child's list of vaccines, too.

To help parents zero in on the most crucial shots, Local 4 asked Dr. Eden Wells, an expert in preventative medicine at the University of Michigan School of Public Health, to share the top four shots she thinks are most critical for kids to get right now and why.

The MMR vaccine, which protect against measles, mumps and rubella topped her list.

"Measles actually has the highest ability to transmit from one person to another that we know of in any of the infectious diseases. It's the most infectious disease," said Wells. "The number of cases just in the first half of this year makes us on course for a very severe year."

Children should receive two doses of the MMR vaccine before they start kindergarten, but some miss that second dose.

Another critical shot protects against pertussis.

"Pertussis, the whooping cough disease. We've been having a lot of problems here in Michigan with that, especially in our elementary and high schools," said Wells.

The whooping cough vaccine is called DTaP or Tdap. It's given in 5 doses to very young children and again in the tween or teen years.

"In our teenagers, it may be more of a chronic cough, but this is a disease that, even if it doesn't cause a lot of problem for the teenager, it may cause severe problems for younger children or the elderly that may be within the family, and these infections have been spreading widely through our high schools to the point where they've had to send children home, keep children out of school who are unvaccinated," said Wells.

The third essential shot won't be widely available until September, but put it on your list now. It's the flu vaccine.

"Influenza attacks children and it can kill children," said Wells. "Even in children who don't necessarily have other medical illnesses."

This year, the CDC is recommending the nasal spray flu vaccine in particular for healthy children ages 2 to 8, because studies find it's more effective than the shot in that age group.

Wells wrestled with picking a fourth, but finally decided on the HPV vaccine for tween or teenage girls and boys.

"This virus actually has been linked to a number of cancers. In women, it may be cervical cancer, but it's actually been commonly seen in both men and women for other forms of cancer," said Wells.

"We have found just with the advent of, the invention of this vaccine, that the incidence of these types of cancers are decreasing."

Wells said it's important for parents to check with their child's pediatrician to make sure they aren't missing any vaccines.

"We do recommend that all the recommended vaccines from Centers for Disease Control be given to your child and that they should be up-to-date."

To see which vaccines are recommended for children from birth to age 6, click here.

To see which vaccines are recommended for children and teenagers from age 7 to 18, click here.

Immunization Station

Children's Hospital offers no-cost vaccinations to children less than 19-years-old who are uninsured, underinsured, Medicaid eligible, American Indian or Alaskan Native through the Vaccines for Children program.

The Immunization Station is a walk-in clinic, located on the second floor of the Children's Hospital Specialty Center-Detroit, 3950 Beaubien. It is open Mondays, Tuesdays and Thursdays from 9:30 a.m. to 4 p.m.

Because of the high volume of children needing service during back-to-school time and school exclusions, clinic hours may be adjusted accordingly. Please contact the clinic (313-832-8430) to verify hours on those days.