Summary BNF Chapter 13 Notes - Vaccination

PRINCIPLES OF VACCINATION
BASIC RECAP:
- Immunity = A person’s ability to resist an infection/toxin via a targeted immune
response specifically against that pathogen/toxin
- This targeted immune response normally involves ANTIBODIES (Abs)

- Immunity can be developed in TWO WAYS:
1- Naturally becoming infected
2- Vaccination against the pathogen/toxin
- Vaccination helps avoid the symptoms of the disease (which may have been FATAL)
& stimulates the production of MEMORY CELLS against the pathogen/toxin  this
makes the individual more IMMUNE against it



Vaccines mimic the 1st infection
(w/out causing symptoms)  helps
generate a strong, secondary immune
response upon re-infection



TYPES OF VACCINES:
1- Live attenuated - LAVs (e.g. MMR, Nasal Flu vaccine, RV, BCG)
o Weakened form of the pathogen – is still able to REPLICATE (lifelong immunity)
o Although they’re NOT pathogenic – still a risk of reverting back to a virulent form
o CONTRAINDICATED in PREGNANCY & IMMUNOCOMPROMISED

2- Inactive (e.g. Seasonal Flu Jab - IM)
- Pathogen is KILLED – can NOT revert back to virulent form
- Pathogen can NOT REPLICATE – so immune response is WEAKER (may require
boosters to maintain immunity)
- Safer than LAVs, but duration of immunity is inferior

3- Subunit (e.g. PCV, MenACWY)
- Only includes the immunogenic subunit (ANTIGEN) of the pathogen
- Most antigens/subunits are polysaccharides
- Subunit vaccines are one of the SAFEST options (very low risk of ADRs)

4- Toxoid (e.g. Tetanus & Diphtheria – ToxoiD)
- Inactivated toxins produced from the pathogen (toxoids have antigenic sites)
- Similar safety profile & immune response to SUBUNIT vaccines

VACCINES IN PREGNANCY:
- Delay LAVs until AFTER BIRTH – avoids risk of foetal infection
- All other vaccine types (including flu shot) are SAFE & RECOMMENDED in
PREGNANCY