Can anyone explain why children need boosters (from a medical point of view)

[Mum1369]

I was wondering why children need boosters for vaccinations - specifically DTP, HiB pre-school boosters - when some vaccines only require one dose
I understand that some vaccines are live - but thought that in principle the ones that aren't live - simply allow the system to read a 'code' and identify it
What I don't get is why some vaccines 'wear off' and if this is what happens then why do you only need a pre school booster and then nothing after that again - is it a case of x amount of separate doses give complete immunity ?
And if that is the case - then would missing a vaccination or missing a final vaccination provide you with any immunity at all ?

I only have a cartoon understanding of immunity. But exposure to anything, disease or vaccine, does not guarantee immunity although multiple exposures increase the chances. And immunity can wear off with time. I suspect boosters are aimed at givong some non immune kids a further exposure to increase the chance they will be immune at school. I think they worry more about school age as the school environment tends to be idea for transmission of lots of diseases.

That's an interesting point, I did wonder if maybe the booster was to encourage non immunised children (but thought maybe I was being paranoid) - So do you think immunity does wear off ?

Anyone clever / medical around ?

Immunity can wear off for sure. But I think it takes a while so boosters are aimed at those vaccinated kids who didn't get immunity first time round.

The first time a pathogen is encountered there is a primary response where the lymphocyte B Cells and T Cells specially coding for that pathogen eventually encounter the pathogen and mount a response. This response involves killing the pathogen and also producing some memory cells which hang about primed to attack that pathogen if they encounter it again. Depending on the pathogen these survive for months to years, some last for life but many don't.

The second time it is encountered more memory cells are produced and these stay around longer and in addition IgG antibodies are also made and these also hang about and act like sensors for that pathogen, latching on and making chemical signals if they encounter that specific pathogen.

Each time the pathogen is encountered after that further memory cells and IgG antibodies are made and they last longer.

Crikey oddboots! Thanks - that makes sense ! So in laymans terms..does a child still have any immunity if they miss the last booster (or does it depend on the particular child?)

They should (although there are no guarantees) have some immunity without the last dose, many will have very good immunity, most will have fairly good, some will have practically none and some would still have none even with a booster.

Immunology is still a developing area of study, there are new discoveries and surprises all the time, I wish I could give you a clearer answer.

If there is something in particular of concern then you could ask about getting a blood test to check for antibodies.

Thanks - that's exactly the kind of information I was looking for!