The yellow fever vaccine protects against the yellow fever virus, a serious mosquito-borne infection found in parts of tropical Africa and Central/South America.
Yellow fever is a viral infection spread by infected Aedes mosquitoes. While some people experience mild flu-like symptoms, it can progress to a severe phase involving high fever, jaundice (yellowing of the skin/eyes), kidney failure, and internal bleeding.
Anyone living in or travelling to high-risk areas who is not immune can catch it.
Some people have a higher chance of developing serious complications from yellow fever:
Unvaccinated travelers visiting high-risk endemic zones.
Older adults (aged 60 and over), who face a higher risk of both severe yellow fever and severe vaccine-related side effects.
Pregnant or breastfeeding women, who face increased risks if infected.
The vaccine is recommended for individuals aged 9 months and older who are travelling to, or living in, countries where there is a risk of yellow fever transmission.
It is also required for people travelling to countries that demand an International Certificate of Vaccination or Prophylaxis (ICVP) as an entry condition.
This includes:
Travellers and international workers going to high-risk areas in sub-Saharan Africa, Central America, South America, and parts of the Caribbean.
Laboratory staff who may be exposed to the wild-type yellow fever virus through their work.
The vaccine is not given to individuals with severe egg allergies or severely weakened immune systems, as it contains a small amount of the live virus.
It is also strictly contraindicated for people with a history of thymus gland disorders (such as myasthenia gravis or thymectomy).
The virus in the vaccine is weakened so it’s safe for most people, but it could cause severe illness if you have a compromised immune system or a thymus disorder.
The yellow fever vaccine is a live vaccine and contains a small amount of weakened yellow fever-causing virus.
The vaccine stimulates your immune system to produce neutralizing antibodies that will help protect against yellow fever.
The vaccine is given as a single injection, usually into the upper arm, at least 10 days before travelling to allow full immunity to develop.
It’s been shown that a single dose provides effective immunity in over 95% to 99% of people vaccinated.
For the vast majority of travellers, a single dose gives lifelong protection, meaning a booster shot is generally not needed (and the vaccination certificate remains valid for life). Booster doses are only advised in rare circumstances, such as for specific high-risk lab workers or people vaccinated while severely immunocompromised.
