I am a Practice Nurse.
Please go to Travel Health pro website. This is the bible of travel health.
If you check under countries to be visited you will get all of your info there.
YF vaccine risks are much higher for the over 60s. If the country you are visiting require proof of vaccination then you will need an exemption certificate.
Countries where YF is a problem ie a risk to yourself you will need to be scrupulous with your insect avoidance measures.
Hope this helps.