Yellow Fever Vaccine

Yellow fever vaccine consists of a live, but altered, strain of the yellow fever virus called 17D. The 17D vaccine has been used commercially since the 1950s. It is highly effective with over 90 percent of persons vaccinated developing a measurable immune response after the first dose.

The 17D vaccine should not be given to infants, pregnant women, and anyone with a diminished immune capacity, including persons taking immune-suppressing drugs.

Many countries require any traveller arriving from a country where yellow fever is present to have an up-to-date yellow fever vaccination. If a traveller is arriving from a country where yellow fever is present, the government may require the traveller to present proof of yellow fever vaccination.

Vaccination is generally recommended for travellers older than 9 months of age who plan on visiting high-risk areas.

What are the side effects?

This vaccine is very safe, with few adverse reactions having been reported and millions of doses administered.  Although the vaccine is considered safe, there are risks involved.  The majority of adverse reactions result from allergic reaction to the eggs in which the vaccine is grown.  In addition, there is a small risk of neurologic disease and encephalitis (inflammation of the brain).

Persons greater than 60 years old or who have had their thymus removed or have a thymus disorder, such as myasthenia gravis, DiGeorge syndrome, or thymoma should discuss vaccination with their physicians. Women between the ages of 56 and 76 without autoimmune disease or thymoma may be recommended for vaccination. Men in this age group are at an increased risk that is difficult to quantify. Travel to areas where the virus is circulating should be delayed until the risk of acquiring yellow fever has abated. People aged 77 or older should be warned that they are at increased risk and should avoid travel to areas wehre the virus is active.

When determining whether a patient should receive yellow fever vaccine, the patient and clinician should discuss the risk for travel-associated yellow fever disease according to the season season, destinations and duration of travel, likelihood of exposure to mosquitoes while traveling, and vaccination status, and weigh them against risks associated with vaccination.

What is the dosage schedule?

Vaccination should be received 10 days prior to travelling to a high-risk area. The World Health Organization's Strategic Advisory Group of Experts on Immunisation (SAGE) has reviewed the latest evidence and recommended that a single dose of vaccination is sufficient to confer life-long immunity against yellow fever. There is no need for booster vaccination.