Table of Contents
Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes. The "yellow" in the name refers to the jaundice that affects some patients. The yellow fever virus is a disease that affects many parts of Africa and Latin America. It’s important to know the symptoms of yellow fever so the patient can be treated accordingly, although there is no specific cure for the virus itself. Prevention is key with yellow fever and vaccination numbers need to be improved in targeted countries. Read on to learn more about the yellow fever virus.
Yellow fever key facts (Source WHO)
- Up to 50% of severely affected persons without treatment will die from yellow fever.
- According to the a recent yellow fever analysis, there are an estimated 200 000 cases and up to 30 000 deaths due to yellow fever per year.
- The virus is endemic in tropical areas of Africa and Latin America, with a combined population of over 900 million people.
- The number of yellow fever cases has been decreasing over the past number of years since the launch of Yellow Fever Initiative in 2006.
- There is no specific treatment for yellow fever. Treatment is symptomatic, aimed at reducing the symptoms for the comfort of the patient.
- Vaccination is the most important preventive measure against yellow fever. The vaccine is safe, affordable, and highly effective. The vaccine provides effective immunity within 30 days for 99% of persons vaccinated.
Yellow fever symptoms
Once contracted, the yellow fever virus incubates in the body for 3 to 6 days, followed by infection that can occur in one or two phases. The first, "acute", phase usually causes fever, muscle pain with prominent backache, headache, shivers, loss of appetite, and nausea or vomiting. Most patients improve and their symptoms disappear after 3 to 4 days.
However, 15% of patients enter a second, more toxic phase within 24 hours of the initial remission. High fever returns and several body systems are affected. The patient rapidly develops jaundice and complains of abdominal pain with vomiting. Half of the patients who enter the toxic phase die within 10 to 14 days, the rest recover without significant organ damage. It’s important to be aware of yellow fever symptoms so patients can get the support they need.
Populations at risk of yellow fever
At risk are 44 endemic countries in Africa and Latin America, with a combined population of over 900 million. In Africa, an estimated 508 million people live in 31 countries at risk. The remaining population at risk are in 13 countries in Latin America, with Bolivia, Brazil, Colombia, Ecuador and Peru at greatest risk.
Small numbers of imported cases occur in countries free of yellow fever.
The latest numbers reported between the last quarter of 2023 and February 2024, state that 8 countries (Cameroon, Chad, Republic of the Congo, Democratic Republic of the Congo, Guinea, Niger, Nigeria, South Sudan) have reported active yellow fever transmissions and confirmed yellow fever cases.
In 2016, Angola had one of the worst outbreaks seen, with a total of 4306 suspected cases and 376 deaths. According to Angolan Health Minister, Luis Sambo, the disease spread to 16 of the country's 18 provinces, despite a preventative vaccination campaign launched in February 2016 which reached 6 million of the capital's 7.4 million inhabitants.
On the on 23 December 2016 Angola announced the end of the yellow fever outbreak, after no new cases were reported for the past 6 months.
Transmission
Several different species of the Aedes and Haemogogus mosquitoes transmit the virus, which is an arbovirus of the flavivirus genus, and the mosquito is the primary vector. It carries the virus from one host to another, primarily between monkeys, from monkeys to humans, and from humans to humans.
Treatment
There is no specific treatment for yellow fever, only supportive care to treat dehydration, respiratory failure, and fever. Associated bacterial infections can be treated with antibiotics. Supportive care may improve outcomes for seriously ill patients, but it is rarely available in poorer areas.
Yellow fever prevention
Vaccination is the single most important measure for preventing yellow fever. In high-risk areas where yellow fever vaccine coverage is low, prompt recognition and control of outbreaks through immunisation is critical to prevent epidemics. To prevent outbreaks throughout affected regions, vaccination coverage must reach at least 60% to 80% of a population at risk.
A single dose of yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease and a booster dose of yellow fever vaccine is not needed.
People who should not be vaccinated include:
- Infants aged less than 9 months (with the exception that infants aged 6-9 months should be vaccinated during an epidemic where the risk of disease is higher than the risk of an adverse effect of the vaccine);
- Pregnant women – except during a yellow fever outbreak when the risk of infection is high;
- People with severe allergies to egg protein
- People with severe immunodeficiency due to symptomatic HIV/AIDS or other causes, or in the presence of a thymus disorder.
If you are planning to travel to an area where you may be at risk of yellow fever, make sure you are vaccinated before making your trip and get the yellow fever vaccine well in advance.
Under regulations set out by the WHO, anyone travelling to a country or area where there is a risk of picking up or spreading the virus that causes yellow fever must h.ave an International Certificate of Vaccination or Prophylaxis (ICVP).
For a list of all countries which require an ICVP, click here.
"All Allianz Worldwide Care insured members residing in an endemic yellow fever country are fully covered for the vaccination and/or treatment after infection." Dr. Ulrike Sucher, Medical Director at Allianz Worldwide Care.
If you are an employer and would like more information on international health insurance plans for employees, please visit:
**→ Corporate Group Scheme International Health Insurance**
For an individual international health insurance quote, please visit:
**→ International health insurance**
Are you moving abroad?
Before venturing to another country, make sure you have a health insurance plan you can rely on
Meet the author
Allianz
At Allianz Partners, Health, our blog is crafted by a team of experts dedicated to providing valuable insights and guidance on global health and insurance topics. With a focus on expatriates, international businesses, and individuals navigating healthcare abroad, our authors bring a wealth of knowledge and experience to every article.
We aim to deliver practical advice, industry updates, and actionable tips to help you make informed decisions, whether you're exploring international health insurance, managing employee health plans, or staying informed about the latest healthcare trends. Trust our blog to be your go-to resource for navigating the world of global health and insurance.
If you are a member and have been affected by any of the issues discussed in this article please contact our helpline today to find assistance.
