SAN ANTONIO -- Parents shopping for backpacks and pencils ahead of the upcoming school year may want to add immunizations to their to-do list.

Doctors at CentroMed Noemi Galvan Eling Clinic say children need several, state-mandated vaccinations by the time they set foot inside their preschool classes.

"Four-year-olds need their measles, mumps, rubella and varicella vaccines along with their tetanus/ pertussis and diphtheria and polio," said Dr. Juan Parra, a director of pediatrics.

The junior high school kids are also a target for back-to-school shots. Parra said they'll need their meningococcal and last booster for tetanus/ pertussis.

"We also high recommend the human papillomavirus vaccine,” he said.

The HPV vaccine prevents infection of certain types of human papillomavirus. It's not required by law to receive one for school purposes.

"We recommend to start at 11 years of age but can start as early as 9 years of age," Parra said. 

Doctors don't recommend opting out of vaccinations but suggest consulting with your child's pediatrician for the best option.

"Being healthy is incredibly impactful for their learning. We want your children healthy,” said Parra.

Saturday, the CentroMed clinic along with Rackspace and Back 2 School America gave away free school supplies to the thousands of students whom received vaccines in their clinics over the summer months.