Yellow Fever Vaccines
Yellow Fever Vaccines
Safe and effective yellow fever vaccines have been available for more than 80 years, says the U.S. CDC. The yellow fever vaccine is a live, weakened form of the virus. It is given as a single subcutaneous (or intramuscular) injection.
Vaccination is recommended for people aged 9 months or older and who are traveling to or living in areas at risk for the yellow fever virus, such as in Africa and South America. The CDC suggests speaking with a healthcare provider to determine if you need a yellow fever vaccination or a booster shot before your trip to an area at risk for yellow fever.
Yellow Fever Vaccines
YF-VAX Vaccine: YF-VAX is prepared by culturing the 17D-204 strain of yellow fever virus in living avian leukosis virus-free chicken embryos. The vaccine contains sorbitol and gelatin as a stabilizer, is lyophilized, and is hermetically sealed under nitrogen. No preservative is added. YF-Vax is licensed in the USA and expects to become available in late 2020.
Stamaril Vaccine: Stamaril is a live, attenuated yellow fever vaccine that contains the active substance Yellow fever virus 17D-204 strain produced in specified pathogen-free chick embryos. Stamaril has been offered in Europe and other countries for decades. Stamaril yellow fever vaccine is currently distributed in over 70 countries and is available in the USA during 2020.
Yellow Fever Vaccine News
July 28, 2020 - Changing temperature and rainfall across Africa could increase yellow fever deaths by up to 25 percent by 2050. This is according to new modeling of the burden of yellow fever by scientists at Imperial College London and the WHO. It suggests that some East African countries including Ethiopia and Somalia may be increasingly impacted by yellow fever in the coming decades and that future vaccine programs will need to counteract this.
September 30, 2019 - Oregon Health & Science University spinoff Najít Technologies, Inc., of Beaverton, Oregon, will test a yellow fever version of the HydroVax vaccine platform it licensed from OHSU. A $3.1-million grant from the National Institutes of Health to Najít will enable Duke University to lead the Phase 1 human clinical trial, and OHSU to study how trial participants’ immune systems respond to the yellow fever vaccine. The trial is expected to take up to a year to complete.
July 19, 2019 - A Randomized Phase I Clinical Trial of HydroVax-YFV, a Novel Inactivated Yellow Fever Vaccine.
Yellow Fever Vaccine Indication
For most people, a single dose of yellow fever vaccine provides protection, and a booster dose of the vaccine is not needed. However, travelers going to areas with ongoing virus outbreaks may consider getting a booster dose of yellow fever vaccine if it has been 10 years or more since they were last vaccinated. Certain countries might also require a booster dose of the vaccine prior to granting entry.
Some people may have an increased risk of developing a reaction to the vaccine, but may still benefit from being vaccinated, says the CDC. Contraindications include severe hypersensitivity to egg antigens and severe immunodeficiency.
Yellow fever vaccines provide effective immunity in about 10 days for 80-100% of people vaccinated, and within 30 days for more than 99% of people vaccinated, says the WHO.
Yellow Fever Virus Epidemics
Large epidemics of yellow fever occur when infected people introduce the virus into heavily populated areas with high mosquito density and where most people have little or no immunity, due to lack of vaccination. In these conditions, infected mosquitoes of the Aedes aegypti species transmit the virus from person to person.
Forty-seven countries in Africa (34) and Central and South America (13) are either endemic for, or have regions that are endemic for, yellow fever, said the WHO, as of May 2019.
The U.S. CDC publishes a list of epidemic countries on this webpage. And the WHO publishes its list on this webpage.
Yellow Fever Virus Overview
Yellow fever is an acute viral hemorrhagic disease transmitted by infected mosquitoes. The "yellow" in the name refers to jaundice that affects some patients, says the WHO.
Symptoms of yellow fever include fever, headache, jaundice, muscle pain, nausea, vomiting, and fatigue. A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days.
Yellow Fever Diagnosis
Yellow fever is difficult to diagnose, especially during the early stages. A more severe case can be confused with severe malaria, leptospirosis, viral hepatitis, other hemorrhagic fevers, infection with other flaviviruses, and poisoning says the WHO.
Polymerase chain reaction testing in blood and urine can sometimes detect the virus in the early stages of the disease. In later stages, testing to identify antibodies is needed.
Yellow Fever FAQs
Note: The content on this page has been aggregated from the WHO, US CDC, research studies, and has been reviewed by healthcare providers, such as Dr. Robert Carlson.