Yellow Fever: What You Need To Know

1. What is yellow fever and how is it transmitted?

Yellow fever is a viral infection transmitted by specific types of mosquitoes, and is predominantly found in parts of Africa and South America. Symptoms include fever, headache, jaundice (hence the name 'yellow' fever), muscle pain, nausea, vomiting, and fatigue. A small proportion of patients who contract the virus develop severe symptoms which can be potentially life-threatening.

2. Why is a yellow fever vaccination important for certain travelers?

The Yellow Fever Vaccine is an effective protection mechanism against yellow fever disease. It's essential for travelers going to yellow fever endemic areas because it offers immunity against the virus. Some countries require proof of vaccination as a condition of entry. Vaccination is also recommended for travelers to these areas, especially if they plan to be outside or are traveling during peak mosquito feeding times.

3. What is the effectiveness of the yellow fever vaccination?

The Yellow Fever Vaccine is highly effective, providing immunity for most people [>80%] after just 10 days. This protection is usually long-lasting, providing a lifetime of protection for many people.

4. Are there any side effects or risks associated with the Yellow Fever Vaccine?

Most people do not have any serious reactions to the Yellow Fever Vaccine. Mild side effects such as a sore arm around the injection site, or transient headaches and muscle aches may occur, which usually disappears within several days. Serious side effects are rare but can occur, and a designated health care professional with experience in prescribing Yellow Fever vaccination should deem the appropriateness of the vaccine for you.

5. Are there certain individuals who should NOT receive the Yellow Fever Vaccine?

Yes, in select circumstances certain individuals should not get the vaccine, including infants younger than 9 months old, pregnant women, people with severe allergies to any component of the vaccine, and those with a weakened immune system due to certain health conditions.

6. What precautions can individuals who cannot receive the vaccine take?

If you are not sure whether you should get the vaccine, consult with a travel medicine specialist or another healthcare provider. For those who can't receive the vaccine, alternative precautions like judicious mosquito avoidance measures are reinforced and consideration of a Yellow Fever Waiver Certificate may be provided.

For more detailed information on Yellow Fever, please see The Canadian Immunization Guide from the Government of Canada at