Riley Nixon wasn't yet two years old when he woke up with vomiting and cold-like symptoms and was rushed to hospital.

"(We) got warned he's probably not going to make it," his mum, Amy Wales, said.

"It wasn't until four days later they finally gave us the all clear that he will make it but not without sacrifices."

The family have become advocates for free meningococcal B vaccinations and were on hand as Health Minister Stephen Wade announced the program on Wednesday.

The policy will provide immunisations for children aged up to 12 months and catch-up programs both for children aged under four and adolescents.

"It currently costs parents up to $500 for a full vaccination course to immunise their children - a cost which is out of reach for many," Mr Wade said.

The vaccinations will be available from October 1 for infants and children and from early 2019 for students in years 10 and 11 as well as young people aged between 17 and 20.

SA Health chief medical officer Paddy Phillips said with 372 cases and 14 deaths since 2000, the program was designed to target those most at risk.

"We know that meningococcal B disease occurs more frequently in infants and children up to four years of age and young adults aged between 15 to 20 years of age," Professor Phillips said.

"This program would prevent about 12 cases of meningococcal B disease each year and prevent one death every two years, as well as reduce the amount of disability experienced by those who survive the disease."

The vaccination program was proposed by the previous Labor government ahead of the March election.

Ms Nixon, who vaccinated Riley after the disease struck, encouraged all parents to take up the offer and immunise their children as soon as possible.

"If it helps even one person not go through what we've been through, it's worth every cent," she said.

"What's a needle if it's going to save your child's life?"

Australian Associated Press