Gelatine derived from pigs is used in some live vaccines as a stabiliser to protect live viruses against the effects of temperature. Gelatine in vaccines is highly purified and hydrolysed (broken down by water), so it is different from the natural gelatine used in foods. For example, very sensitive scientific tests have shown that no DNA from pigs can be detected in the nasal flu vaccine (Fluenz). These tests show that the gelatine is broken down so much that the original source cannot be identified.
There have been a tiny number of cases of allergic reaction to vaccines containing gelatine (about one case for every 2 million doses of vaccine). People with a known allergy to gelatine should seek expert advice before receiving vaccines containing gelatine.
Members of Muslim or Jewish religious communities may be concerned about using vaccines that contain gelatine from pigs (porcine gelatine). According to Jewish laws, there is no problem with gelatine or any other animal substance if it is used in a product that does not go into the mouth. Some Muslim leaders have also ruled that the use of gelatine in vaccines does not break religious dietary laws, because it is highly purified and it is also injected or inhaled rather than ingested (eaten).
Gelatine is found in these vaccines used in the UK:
More information can be found in the NHS leaflet 'Vaccines and porcine gelatine' . This information is also available in Arabic , Bengali and Urdu .