The National Adult Immunisation Schedule (NAIS) is Singapore's guide to the vaccines adults aged 18 and older should receive, according to age, pregnancy, occupation, medical conditions, previous doses and immunity. It covers 12 vaccine-preventable diseases, and now includes shingles vaccination and the PCV20 pneumococcal vaccine for recommended groups.
Some vaccines are recommended routinely by age; others because of pregnancy, chronic disease, immune suppression, work or travel exposure, or missing childhood immunity. The type and timing of vaccines you have already had decide whether a catch-up or extra dose is needed.