An Indonesian pharmaceuticals company has said it is racing to produce a "halal" form of the measles-rubella vaccine amid concerns that conservative Muslim parents might deny their children’s inoculation on the grounds that it contains traces of pork.

The state-owned Bio Farma confirmed its research after the Indonesian Ulema Council (MUI), considered to be the Southeast Asian nation’s most authoritative Muslim body, declared the vaccination to be ‘haram’, or religiously forbidden.

MUI quickly clarified that in light of the dangers posed by the diseases, Muslims should continue to use the vaccine until an alternative was found.

However, its initial declaration that the vaccine was ‘unclean’ has provoked fears that conservatives may still shun the injection for religious reasons.