Diptheria, polio & tetanus (DPT)
The risk of malaria won't rear it's head until we reach southern China and (the risk) will be prevalent throughout Southeast Asia thereafter (especially in more rural areas). It is unlikely that we'll take anti-malarial medication with us from the UK, but will be able to pick up what we need nearer the time (or get stuff sent to us to collect from post restante). Many (cycling) travellers don't take anti-malarials for several reasons including after effects, but as we will be spending considerable time in rural parts of Southeast Asia, the risk is too high to ignore...it only takes one bite after all!
There were many factors to consider when deciding on which injections to have; and we often found ourselves weighing up the balance between risk factor and cost. Initially, we didn't realise that if you 'shop around' you may be able to get the vaccinations much cheaper than simply approaching your local GP surgery (note that Hep. A, Thyphoid and DPT are available free on the NHS as is Hep. B if you're deemed to belong to a 'high risk group').
The Travel Health Consultancy in Exeter, comes highly recommended (obviously if you live within a reasonable travelling distance!) Not only were their costs considerably cheaper than our local Health Centre (Kingskerswell) but their general advice and knowledge was fantastic!
Other diseases which we considered (but ultimately decided against) taking medication for include:
Tick borne encephalitis
Of these, the tick borne encephalitis presents the greatest risk for us, but through a combination of taking sensible precautions (avoiding frolicking naked in the forests of mid - eastern Europe!) and making sure that we get through the high risk areas before the height of the season, we should be fine.