Yellow fever is caused by a virus and is passed via mosquito bites. It can cause severe illness and can be deadly with an estimated 200,000 cases and 30,000 deaths each year. There is currently no specific treatment for yellow fever. That’s why vaccination to reduce morbidity and mortality is key.
Risk of getting yellow fever varies according to season, location, activities, and duration of their travel. Yellow fever “hot spots” include Africa and South America. Since 1965, International Health Regulations (IHR) have allowed countries to require yellow fever (YF) vaccination within 10 years for entry. Requiring proof of vaccination is at the country’s discretion. In April 2013, a WHO (World Health Organization) Strategic Advisory Group of Experts concluded that a single dose of yellow fever vaccine gave lifelong immunity. In May 2014, the WHO Health Assembly adopted an amendment that extends YF vaccine protection to the life of the person vaccinated. The legal effective date of this IHR would not be until June 2016.
The CDC has reviewed indications for Yellow Fever vaccination and agrees that a single vaccine dose provides lifelong protection for most travelers with a few exceptions. Additional doses of yellow fever vaccine are recommended for women who were pregnant when they received their initial dose of vaccine as well as patients with HIV. Also, patients who have had bone marrow transplant after initial yellow fever vaccination need an additional vaccine dose. In addition, travelers who will be in high risk settings (based on season, location, and activities, and duration of stay) may also need an additional vaccine dose every 10 years.