Whooping cough vaccine is in short supply, so South Australian authorities are ensuring children and pregnant women are given priority.

Key points: Grandmother tried numerous chemists, then turned to Facebook

Grandmother tried numerous chemists, then turned to Facebook Stocks of vaccine sell out very quickly

Stocks of vaccine sell out very quickly People other than pregnant women and children might wait weeks for vaccine

An Adelaide grandmother said she trekked from pharmacy to pharmacy in her search for the vaccine and eventually found some stock after putting out a plea on social media.

Suzy Ramone told 891 ABC Adelaide her daughter had been keen for all the family to be vaccinated because her grandson had been born prematurely.

"That means that he's not going to have the normal immunity that other babies have for the first year, so we have to be quite careful — if he gets whooping cough he could die," she said.

Ms Ramone, who works as an 891 radio producer, said it took persistence to find the vaccine in Adelaide.

"I called into about five chemists and none of them had it. None of them knew when they were going to get it," she said.

The Adelaide grandmother said she also phoned more pharmacies without success.

"At that point I was really surprised. I thought how could this happen in Australia that we've run out of a very important vaccine?" she said.

Facebook plea for vaccine

Her next step was to turn to social media.

"I did what I do now for lots of problems, I just went on Facebook and my friends came to the rescue," she said.

"I've got friends who are nurses and friends who work in doctors' offices and friends who work in chemists, so I found a place that did have stock in."

Minister Jack Snelling said lower priority groups might need to wait weeks for vaccination. ( ABC News )

She said that retailer had just received some stock and she was told by her friend of how quickly any fresh supplies sold out.

South Australian Health Minister Jack Snelling said the state could do little other than prioritise the high-risk groups.

"There's a worldwide shortage of whooping cough vaccine and it does mean that we have to prioritise children and pregnant mums, because of course they're the people most at risk," he said.

"Other people like grandparents and so on who aren't as high a priority might have to wait.

"My information is that, if you do have to wait, the wait will be a matter of weeks before you are able to get vaccinated."