Indonesia's top Islamic body issued a fatwa on the use of the measles mumps rubella (MMR) vaccination because it contains traces of pork.
While such religious decrees, or fatwas, are not legally binding, they are highly influential in the predominantly Muslim country and some towns have reportedly already suspended the vaccine.
An MUI official spoke to CNN Indonesia about the dangers of not immunising children and believes the existing vaccine could still be used until a sacred halal alternative is found.