A highly effective and safe vaccine is available for yellow fever. It's given as a single dose injection. The protective effect (immunity) happens within 1 week for 95% of people. The vaccine gives protection for at least 10 years, possibly the rest of your life. However, after 10yrs you will need to have a booster vaccination. If you're planning to go to where there is yellow fever infection, you should be vaccinated at least 10 days before you travel. You will be given an International Certificate of Vaccination or Prophylaxis (ICVP) which becomes valid 10 days after your injection and will need updating every 10 years.
Attribution: BUPA