6in1 includes the following vaccines:
DTPa + HiB + IPV + HEPB
Diphtheria, Tetanus, Pertusiss,
Haemophilus influenza type B,
Inactivated Polio Vaccine and Hepatitis B.

5in1 includes:
DTPa + HiB + IPV
Diphtheria, Tetanus, Pertusiss,
Haemophilus influenza type B, and
Inactivated Polio Vaccine.

18个月打的是Booster啊
https://www.nir.hpb.gov.sg/nir/sv/eservices/eservicesv?ACTION=DISPLAY_IMMUNSCH