Paediatric Vaccines Flashcards
Paediatric Vaccines
A child’s immune system: 20-week foetus to 1 year old
Antibody synthesis begins in foetus at 20 weeks
Infants are reliant on maternal antibodies for the first 2 months
Before 2 months old – can’t vaccinate the child (except premature babies)
Extra antibody production is induced by oestrogen
IgG crosses the placenta in the last 10 weeks of pregnancy
Breast milk transfers sIgA – protects against lung and GI infections (baby is more
likely to develop pneumonia in the first 3 months of life if bottle-fed)
0 to 1 year old – the adaptive immune system is immature
There are many T-cells but these are all naïve so they don’t respond well to antigens
Risk of side effects if given attenuated vaccines – better to use toxoids,
glycoconjugates, recombinant proteins and safe adjuvants
All need 2-3 vaccines
The elderly immune system
Elderly suffer more infections as their T-cells and B-cells die off
T-cells stop living after about 40 divisions
Enhanced risk of respiratory infections
Shingles can occur due to latent chickenpox – sign of secondary immunodeficiency
due to malignant B-cells
B-cell clone can outgrow and become malignant (leukaemia) – process driven by
lifelong EBV infection
Key points
The immune system changes throughout life, and vaccines used at specific times
reflect that
Protection is provided for the first 2 months of life by IgG and sIgA from the mother
Baby in their first month of life are the most vulnerable – vaccinations must start as
soon as maternal antibodies wane at 2 months
Due to the nature of the infant’s adaptive immune system (not full level of antibodies
and naïve relatively unresponsive T-cells) the first vaccines are mostly adjuvanted glycoconjugates and recombinant proteins, inactivated polio virus and the safe attenuated rotavirus vaccine – protect against severe respiratory, gut and meningitis infections
These need several boosters due to immature immune system
When the baby reaches the first year, T-cells are fully functional and can cope with
attenuated vaccines – first MMR, then flu
When the child starts school, the immune system is fully mature and has experienced
a full repertoire of paediatric vaccines
In young adults, girls are offered, girls are offered the HPV vaccine
All 1st year students in university are offered the Men ACWY vaccine to protect them
against meningitis in an optimal transmission environment
In the elderly, the immune system is less effective and vaccines are available to
protect against respiratory conditions and re-activated varicella zoster – shingles
Other vaccines are available for travellers when in endemic regions
