The director of Rutgers Global Health Institute says that the decision of many parents to not vaccinate their children could lead to dangerous conditions around the world.

New Jersey requires children entering school and day care to have several immunizations. But many parents have chosen not allow their kids to get the shots.

“As a parent myself, I can understand the worry about injecting something that’s foreign into a young child,” says Dr. Richard Marlink.

But Marlink says that as the director of the institute he knows that vaccines work, are safe and are necessary to global health.

“Vaccines have literally saved millions and millions of lives,” he says.

Marlink says that the vaccines undergo the highest level of pharmaceutical testing. He is asking those who are against vaccinations to “trust science.”

“In the U.S. measles and pertussis are increasing. There’s been pockets of parents or communities that have refused vaccination and that’s when those diseases come back into the communities,” says Marlink.

MORE: New Jersey doctors talk vaccinations

MORE: Interview with Sue Collins, of NJ Coalition for Vaccination Choice

But there are many in New Jersey who say that there are still many questions surrounding vaccinations.

“To keep putting chemicals into children’s still developing immune systems and not expect detrimental outcomes, I think is naïve,” says Sue Collins with New Jersey Coalition For Vaccination Choice.

Collins says that many vaccines contain dangerous ingredients and have dangerous side effects.  Her group says that it is time to stop mandated vaccinations and let parents decide what's best for their kids.

“Right now children are expected to get 72 doses of 16 vaccines,” says Collins. “We keep adding more and more to the schedule. And what is lacking is we’re not really giving parents options to make these decisions.”

New Jersey does allow for some medical and religious exemptions for vaccinations.