A meningococcal vaccine has been recalled in Australia over concerns about rust found in some doses.
The vaccine Meningitec was replaced in July 2013 by a new vaccine called Menitorix, which is given to children at 12 months as part of the National Immunisation Program.
But some of the remaining doses of Meningitec could potentially be contaminated by rust and oxidised stainless steel from manufacturing equipment.
Australia's drug regulator says all doses of the vaccine must be returned to the supplier, Emerge Health Pty Ltd.
Health authorities say there is no need for people to be concerned because the risk that an Australian has received a contaminated dose of vaccine is very low.
Sydney GP Brian Morton says he has some vials of the old vaccine in the fridge at his practice, and will be returning them to the manufacturer.
He says there is little chance a health professional would use a contaminated vial.
"Any contamination with iron would be visible and you'd see that when taking the vaccine out of the box or loading it into the syringe," he said.
"Even if it's in a pre-filled syringe you have to get the air out it, so you actually inspect the contents of the syringe prior to putting it in someone's arm, so it would be visible."
There are many different strains of meningococcal disease - the most common in Australia are B and C.
The vaccination program has reduced the incidence in Australia to fewer than 100 cases a year.
The Therapeutic Goods Administration said administration of an affected dose may result in symptoms such as redness, pain, swelling around the injection site or allergic responses.
If administered to a baby less than 7kg in weight there is a potential risk of iron toxicity, it said.