Endemic yellow fever was eliminated in the United States in 1905, way before the first yellow fever vaccine was developed (1935) and licensed (1953).
How did that work?
Yellow fever is a now vaccine preventable disease that is spread by mosquito bites.
In the United States, it was actually eliminated by controlling the Aedes aegypti mosquitoes that spread the yellow fever virus before the vaccine was even developed. These control efforts were also done in Cuba, Panama, and Ecuador, etc., places where yellow fever was common and led to outbreaks in the United States.
Why Haven’t We Eradicated Yellow Fever?
So why is yellow fever still a problem if we can control the the Aedes aegypti mosquitoes that carry the yellow fever virus?
“Mosquitoes breed in tropical rainforests, humid, and semi-humid environments, as well as around bodies of still water in and close to human habitations in urban settings. Increased contact between humans and infected mosquitoes, particularly in urban areas where people have not been vaccinated for yellow fever, can create epidemics.”
Yellow fever: Questions and Answers
It’s because we can control the mosquitoes in urban areas, in and around cities. You can’t really control or eliminate mosquitoes in tropical rain forest regions, which is why it is difficult to eradicate yellow fever, malaria, dengue fever, and other mosquito borne diseases.
But we have a vaccine, don’t we?
“Eradication of yellow fever is not feasible since we are unable to control the virus in the natural animal hosts.”
Yellow fever: Questions and Answers
Unfortunately, we aren’t the only ones who can become infected with yellow fever. Monkeys get infected with the yellow fever virus in rain forests, infect Haemagogus and Sabethes mosquitoes, which bite people in those areas.
“Urban transmission of yellow fever virus occurs when the virus is spread from human to human by the Aedes aegypti mosquitoes.”
Yellow fever – Brazil
That likely means that yellow fever will never be completely eradicated, unlike small pox.
Yellow Fever Vaccines Myths
But just because yellow fever can’t be eradicated doesn’t mean that it can’t be eliminated.
A single dose of the yellow fever vaccine is safe and provides life-long protection for 99% of people.
“Vaccination is the most powerful known measure for yellow fever prevention: a single dose can provide life-long immunity at a cost of approximately US$1.”
WHO on Eliminating Yellow Fever Epidemics (EYE) Strategy: Meeting demand for yellow fever vaccines
And as cases of yellow fever increase in some countries, like Brazil, getting more people vaccinated is the only way to stop this deadly disease.
Tragically, anti-vaccination myths and misinformation may be keeping folks from getting vaccinated and protected. Propaganda and anti-vaccine scare videos have them thinking that the yellow fever vaccine is dangerous, part of a conspiracy to depopulate the world, or that it doesn’t work.
It is also important to know that:
You should not skip getting the yellow fever vaccine if you are traveling to an area where yellow fever is endemic, including many parts of areas of Africa and South America.
- While you are most at risk during the rainy season, especially during outbreaks, it is also possible to get yellow fever during the dry season.
- Yellow fever is a serious, life-threatening disease.
- There is no cure for yellow fever.
- While serious side effects to the yellow fever vaccine have been reported, including anaphylaxis, yellow fever vaccine-associated neurologic disease (YEL-AND), and yellow fever vaccine-associated viscerotropic disease (YEL-AVD), they are very rare.
- The yellow fever vaccine is a live virus vaccine, but shedding is not an issue. Unless at a high risk of exposure, getting the yellow fever vaccine is usually not recommended if you are pregnant or breastfeeding though.
- It is not usually necessary to get a booster dose of the yellow fever vaccine.
- Some countries require proof of yellow fever vaccination if you have traveled from a country where there is still a risk of getting yellow fever, so that you don’t import yellow fever into their country.
As yellow fever cases are on the rise in Brazil, with an associated increase in travel associated cases, it is important that everyone understand that vaccines are safe and necessary.
What to Know About Yellow Fever Vaccine Myths
Yellow fever cases are increasing and so are anti-vaccine myths about the yellow fever vaccine, which are keeping some folks from getting vaccinated and protected, even as they are threatened by a potential outbreak.
More on Yellow Fever Vaccines Myths
- WHO – Yellow fever fact sheet
- WHO – Yellow fever – Brazil
- WHO – Yellow fever: Questions and Answers
- WHO – Eliminating Yellow Fever Epidemics (EYE) Strategy: Meeting demand for yellow fever vaccines
- When WhatsApp’s Fake News Problem Threatens Public Health
- WHO – Yellow fever vaccination requirements and recommendations
- CDC – Yellow Fever Frequently Asked Questions
- Could Yellow Fever Return to the United States?
- Yellow Fever Timeline: The History Of A Long Misunderstood Disease
- Yellow fever epidemics and mortality in the United States, 1693-1905.
- The elimination of urban yellow fever in the Americas through the eradication of Aedes aegypti.
- WHO – Yellow fever outbreak Angola, Democratic Republic of the Congo and Uganda 2016-2017
- Yellow Fever ACIP Vaccine Recommendations
- CDC – Yellow Fever (Yellow Book)
- CDC – Testing of Selected Patients with Serious Adverse Events Potentially Related to Yellow Fever Vaccination
- FDA – YF-Vax (package insert)
- History of the Yellow Fever Vaccines
- CDC – Yellow Fever Vaccine Course
- WHO – Yellow fever global vaccine stockpile in emergencies
- WHO – Lower doses of yellow fever vaccine could be used in emergencies