The use of pork gelatine in three vaccines used by the NHS has been branded "disappointing" by the Vegetarian Society.
Chief executive Lynne Elliot added that the use of animal ingredients in medicines is "upsetting".
The Muslim Council of Britain said the vaccines are not permitted in Islam unless lives are at risk and there are no alternatives.
Dr Shuja Shafi, the chairman of the council's research and documentation committee, said: "There should be more work towards an alternative.
"We should be trying to find a long-term solution. The needs of the people must be met."