The TTSH Medical Centre
At the entrance at Sinaran Drive at Basement 2 of TTSH, you will see a flight of escalators facing you with the Pharmacy on the left and the Pre Admission Counselling and Evaluation (PACE) Services and the Traveller's Health and Vaccination Centre on the right.
actually GPs also have vaccinations available. can check with your local gp and ask them for advise. The one which I went to recently even have travel kits available for sale. I didn't buy so I dun know what's inside the kit.