Types of vaccine

Live attenuated

• live but 'weakened' pathogen (usually not given in pregnancy, potential harm if immunocompromised) e.g. BCG, oral polio, measles, yellow fever, rotavirus

Killed/inactivated

• pathogen killed by chemical treatment or heat (immune response less compared with live vaccine) e.g. polio SALK, whole-call pertussis

Subunit

specific protein or fragment from pathogen

• (i) protein-based e.g. acellular pertussis, Hep B

• (ii) polysaccharide vaccines (T-cell independent, only stimulates B cells. Poor effect in children) e.g. 23 valent PPSV, meningococcal

• (iii) conjugate vaccines (T-cell dependent, longer immunological memory) e.g. HiB, PCV7, PCV10, PCV13

Toxoid

• chemically inactivated protein exotoxin e.g. tetanus, diphtheria

messenger/mRNA vaccine

• uses synthetic RNA to encode antigen (e.g. spike protein), transfected into immunity cells, stimulate adaptive immune response induces cellular and humoral immunity

Extended Programme of Immunisation

• Launched in 1974 (TB, diphtheria, tetanus [child and mother], pertussis, polio, measles)

EPI schedule

• Pregnant women

• Infants

• Children