Hundreds of worried parents in the region are continuing to call a company offering controversial separate vaccines for measles, mumps and rubella.
Last weekend Direct Health 2000 came to the region for a second time, to offer a course of three jabs to the children of parents worried about the Government-backed MMR triple vaccine.
The clinic was held at the private Woodlands Hospital in Darlington and was inundated with parents wanting to give their children three jabs rather than the single vaccination.
There were 400 places at the clinic and all were booked well in advance of the weekend. Each parent must make four appointments with the clinics - three to get the injections and a fourth in case a child is ill and has to miss a session.
The organisers are now considering setting up a third set of clinics to meet the increasing demand.
Direct Health spokeswoman Kathryn Durnford said: "Because of the surge of demand after the first clinic we decided to put on second opening session.
"Normally we run a course of four visits and there are now two sets of children being treated by us in the Darlington area.
"There was a lot of interest in the second clinic and it was fully booked. Because of the demand we brought extra staff up to Darlington."
Since the last clinic was held in the town, Direct Health 2000 has set up a special 200-strong call centre to take calls from concerned parents wanting to know more about the single jabs.
Ms Durnford said: "Since the last clinic in the region we had a 30 per cent increase in calls and we are getting an average of 700 calls a day from all over the country.
"We had to set up a call centre because our own phone lines were being bombarded with people asking about the possibility of future clinics and people wanting to make appointments at our centre in London could not get through."
The Department of Health has urged parents to ignore the scare stories that MMR can cause autism and bowel disease.
Top medical experts have repeatedly stated that the widely-used triple vaccine is safe and there have been warnings that parents who give their children separate injections may expose them to a higher risk of catching measles.
Parents wanting more information about Direct Health 2000 clinics can contact 0870 443 7070.
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