Infectious Diseases Act (Chapter 137)

Here's the deal on what is required by law in Singapore, regarding vaccinating children (taken from Singapore Statues Online):

Infectious Diseases Act (Chapter 137), Section 46(1):
The parent or guardian of every child in Singapore shall ensure that the child is vaccinated against the diseases set out in the Fourth Schedule.

And the Fourth Schedule:
Diseases against which a child is to be vaccinated
(1) Diphtheria.
(2) Measles.

So it is possible to request your physician to have diphteria-only and measles-only vaccines given to your child. There is no compulsion to use only DTP, DTaP or MMR. There is also no compulsion to use vaccines with thimerosal. By the way, vaccines that guard against more than one pathogen are sometimes known as multi-valent vaccines while those which guard against only one disease are known as mono-valent vaccines.

I am now trying to find out if there is a time frame by which parents or guardians must comply with this legislation. Currently the practice is to give DTP at 3 months and MMR at 15 months. Perhaps it is possible to delay giving a child these vaccines until a year before school-going age, 4 years for kindergarten and 6 years for primary school, when the child's body and immune system are stronger and more settled.