Yellow fever is a life-threatening viral illness that spreads through infected mosquitoes. People traveling to or living in certain areas of Africa and South America are highly susceptible to getting this disease.

Yellow fever is a life-threatening viral illness that spreads through infected mosquitoes. People traveling to or living in certain areas of Africa and South America are highly susceptible to getting this disease.

People suffering from yellow fever experience high fever, liver pain and yellow color affecting the skin (jaundice). If detected early, yellow fever can be controlled. Otherwise, this condition can quickly reach a stage which can be fatal. According to WHO, around 200,000 cases are recorded and 30,000 deaths occur every year due to yellow fever. Getting some knowledge and staying informed of yellow fever symptoms, causes and vaccination is a good idea to prevent the spread of this potential illness and be safe for anyone who might be susceptible.

Who is at Risk?

Anyone who travels to or resides in a place which is occupied by infected mosquitoes is at risk of getting yellow fever.

There are various factors which determine whether a traveler will or will not get yellow fever. These include destination of travel, immunization status, season, length of exposure, participation in outdoor activities and the level of virus transmission at the time of travel. For example, the raining season is a bad time to travel to rural West Africa or South America, as it is the breeding time for mosquitoes. During this season, the risk of catching yellow fever is high.

Most cases of yellow fever happen in 32 countries of Africa and 13 countries of Latin America. Here’s a list of places which should be on your watch-out list, if you happen to be in or around any of these.

Africa

Angola

Benin

Burkina Faso

Burundi

Cameroon

Central African Republic

Chad

Congo, Republic of the

Côte d’Ivoire

Democratic Republic of the Congo

Equatorial Guinea

Ethiopia

Gabon

Gambia, The

Ghana

Guinea

Guinea-Bissau

Kenya

Liberia

Mauritania

Niger

Mali

Nigeria

Senegal

Sierra Leone

South Sudan

Sudan

Togo

Uganda

Central and South America

Argentina

Bolivia

Brazil

Colombia

Ecuador

French Guiana

Guyana

Panama

Paraguay

Peru

Suriname

Trinidad and Tobago

Venezuela

[Source: CDC, Centers for Disease Control and Prevention]

If you are traveling to Brazil soon, you should know that it is under Level 2 Travel Alert, as per CDC. Since early 2018, multiple unvaccinated travelers (not from US) to Brazil have died due to yellow fever infection.

There are other African countries with a low risk of yellow fever and these are Eritrea, Rwanda, São Tomé and Príncipe, Somalia, Tanzania and Zambia. The risk of getting yellow fever in South Africa is higher than South America where it’s not very likely for people to come in contact with monkeys who might carry the yellow fever virus. Plus, a large number of residents in South American countries use vaccines, thereby reducing the risk of transmission.

Signs and Symptoms

The term yellow fever is a combination of ‘yellow’ and ‘fever’, both of which denote the symptoms of the illness. A person who has contracted yellow fever suffers from high fever and yellowing of the skin.

It may take 3-6 days (incubation period) before the symptoms fully develop. This means you won’t notice symptoms immediately after infection. Once the incubation period is over, the patient will start to experience a number of signs and symptoms, in the early stage and the toxic stage.

First (Early) Stage Symptoms

Headache

Fever

Ache in joint and muscles

Nausea

Shivers or Chills

Second (Toxic) Stage Symptoms

Abdominal pain

Jaundice

Join aches

Loss of appetite

Vomiting, sometimes with blood

Bleeding from nose

Kidney, liver failure

Slow heart rate

Brain dysfunction

Many patients recover at the first stage itself. However, some yellow fever patients show the initial symptoms and then the symptoms disappear. After a gap of 24 hours, the symptoms may arise again, which is called the toxic stage. The toxic stage symptoms are severe and could threaten the lives of patients.

According to a survey by WHO, 20 to 50 percent of patients who enter the toxic stage die within a period of two weeks.

Causes

The virus that causes yellow fever is known as flavivirus.

The Aedes aegypti mosquito is the carrier of this virus. The mosquito gets infected after it bites an infected human or monkey.

An infected mosquito carries the virus throughout its lifespan. Monkeys that live in tropical rainforests are believed to have the flavivirus in their blood, particularly in places such as Africa and South America. If a person visits a jungle and gets bitten by an infected mosquito, that person becomes infected and a source of infection for others once back in the community.

When to Visit a Doctor

Early diagnosis helps save the lives of patients. If you have been to a place with a risk of yellow fever and are experiencing symptoms that look like that of flue, you should see a doctor immediately. During consultation, the doctor will ask you several questions to know more about the case. And then, if the doctor gets suspicious that you may have been infected, you’ll be asked to go for a blood test.

It’s only after your blood sample is analyzed, the doctor can be sure whether you have yellow fever virus or not.

Treatments

Unfortunately, there’s no cure for yellow fever.

If there was an antiviral medication to treat yellow fever, doctors would be able to save so many lives. But there isn’t. Patients suffering from yellow fever have to depend only on supportive care in a hospital.

At the hospital, the doctor only focuses on dealing with the symptoms and improving the efficiency of the immune system in patients. If the immune system responds better, the intensity of the infection reduces. In some cases, the doctor may also use plasma transfusion as a form of treatment. Advice is also given to patients to avoid taking pain killers like aspirin. Use of non-steroidal anti-inflammatory drugs can lead to or increase internal bleeding in yellow fever patients.

Supportive care for patients include:

Getting lots of fluid, possibly through veins

Getting oxygen

Bringing the blood pressure to normal

Getting blood transfusion

Getting dialysis, in case of kidney failure

Getting treatment for secondary infections

Patients with yellow fever are kept under constant monitoring and observation. The doctor also ensures that the patient doesn’t get a mosquito bite because it would only spread the infection to other people.

Vaccination – The Most Effective Way to Prevent Yellow Fever

Since there’s no cure for yellow fever yet, the only preventive measure that you have is vaccination. The yellow fever vaccine contains the 17D strain (live and attenuated version) of the virus.

A single shot of this vaccine gives you protection for a span of 10 years. The vaccine boosts the immunity of a person within ten days of getting the dose. As suggested by the Centers for Disease Control and Prevention (CDC), the yellow fever vaccine is safe for anyone aged between 9 months and 59 years, except those people who are highly allergic to some food and proteins or have a compromised immune system. If you are over 60 years and you’re traveling to a country which has a risk of yellow fever, you should consult a doctor regarding vaccination.

Where to Get: The US-licensed yellow fever vaccine (YF-VAX) is available at select travel clinics across the United States. Sometimes, all the clinics may not have a good supply of this vaccine and use Stamaril as an alternative. Currently, there can be a shortage of yellow fever vaccine in US, but you can expect it to be widely available again by mid-2019. For more information, you should contact a nearby clinic in your area or visit this page on the CDC website which helps you search for yellow fever vaccination clinics in multiple states of the US. You can also talk to your doctor for details of clinics that provide the vaccine.

Duration: In most cases, the yellow fever vaccine provides protection for a lifetime. For people who have a high risk of getting this viral infection may be recommended to get another booster dose after 10 years of getting the first shot and obtain new vaccination certificates to produce as required.

Cost: Yellow fever vaccine is affordable for everyone. It’s a good idea to obtain a full price list of travel vaccinations from a clinic that’s close to your place.

Side-Effects: Fortunately major side-effects of yellow fever vaccine are uncommon.. Usually some people may experience some mild symptoms like fever, muscle aches and joint pain shortly after the injection. If you have these mild symptoms, there’s nothing to worry about. Usually, these symptoms disappear within a week. In case, there are signs of an allergic reaction after getting the shot, seek medical help urgently. A booster dose of this vaccine is not recommended for people who have experienced fatal allergic reactions like chest tightness, swelling in face and difficult breathing after the first shot. Older adults may be more likely to have serious side-effects.

Other Methods of Prevention

Vaccination is the only way to keep yourself well-protected when entering a country or city that has a risk of yellow fever. However, there are some recommendations that you can use for the prevention of this disease.

  • Avoid indulging in outdoor activities in a mosquito-infested area
  • Have your arms, hands and legs covered for protection against mosquito bites
  • Choose well-screened accommodation for stay during travel
  • If your accommodation doesn’t have AC or window screens, use netting over beds
  • Use mosquito repellents and other related gear

When you want to keep mosquitoes away, you can either use non-skin repellent or skin repellent. Depending on the situation, you can either apply repellent to your clothing or skin (or both). Due to the presence of chemical ingredients, mosquito repellents can prove to be harmful when used for several hours or days in a row. So, make sure you use mosquito repellents only for the amount of time you’ll be outdoors. Skin repellents should not be used on the hands of infants who are below 2 months of age. Instead, cover their stroller with mosquito netting when outdoors.

9 Facts about Yellow Fever You Should Know

  • Yellow fever is a mosquito-borne disease. It’s called yellow fever because of symptoms including yellowing of skin (jaundice) and high fever.
  • Common symptoms of yellow fever are headache, fever, joint and muscle aches, nausea, vomiting, loss of appetite, fatigue etc.
  • A small percentage of infected patients who enter the toxic stage show severe symptoms and almost half of them die within 1-2 weeks.
  • Though there’s no cure for yellow fever yet, the disease can be controlled by managing symptoms and strengthening the immune system of patients.
  • There are some countries where entry is prohibited for travelers until they produce their immunization certificates.
  • In the past around the 17th and 18th centuries the United States and Europe have witnessed large epidemics of yellow fever, resulting in thousands of deaths.
  • The first ever vaccine for the prevention of yellow fever was discovered by Max Theiler in 1951. Dr. Theiler was awarded with the Nobel Prize in Physiology or Medicine for his excellent, life-saving work.
  • The yellow fever virus is most common in the tropical areas of Africa and Central and South America. If you’re planning to travel to any of these places, make sure you get vaccinated – at least a month in advance.
  • Due to favorable climatic conditions, some parts of Canada too have a high risk of yellow fever infection. So, before you plan a trip to these areas, make sure you are properly informed and vaccinated.

The Bottom Line

Yellow fever is a deadly illness. If you are traveling to an at-risk city or an area where multiple cases of yellow fever have been recorded in the recent past, make sure you get yourself vaccinated before departure.

If you have any questions or doubts, get in touch with a doctor. They’ll explain it all and give you the best advice.

Even after you have been vaccinated, you should never forget to follow other methods of prevention. Throughout the period of your travel, keep yourself protected against mosquito bites. Stay in AC rooms and try to stay indoors when the risk of getting mosquito bites is high. When outdoors, wear protective clothing and use mosquito repellents so that you have a safe travel.

Are there any specific resources available for yellow fever vaccination?

Yes, there are specific resources available for yellow fever vaccination. Some of the resources include a pre-vaccination checklist for yellow fever, a list of contraindications and precautions related to the yellow fever vaccine, a factsheet providing information about yellow fever, a map showing countries with a risk of yellow fever transmission, recommendation maps for yellow fever vaccination, information for travelers about obtaining a replacement international certificate of vaccination or prophylaxis, a poster highlighting that yellow fever vaccination is valid for life, and an informational leaflet specifically for travelers about yellow fever.

What are the guidelines on clinical procedures related to yellow fever vaccination?

The guidelines on clinical procedures related to yellow fever vaccination include the following:

1. International Certificate of Vaccination or Prophylaxis (ICVP): It is required to have a valid ICVP to ensure that individuals have been properly vaccinated against yellow fever. This certificate serves as proof of immunization and may be requested for international travel purposes.

2. Medical letter of exemption: In certain situations, individuals may be exempted from receiving the yellow fever vaccine due to medical reasons. A medical letter of exemption may be required to justify the exemption and provide alternative recommendations for these individuals.

3. Vaccine storage and disposal: Proper storage and handling of the yellow fever vaccine are crucial to maintain its effectiveness. Guidelines should be followed to ensure the vaccine is stored at the correct temperature and that expired or damaged vaccines are appropriately disposed of.

4. Record keeping and consent: Accurate documentation of yellow fever vaccinations is essential for monitoring and reporting purposes. Healthcare providers should maintain comprehensive records of individuals receiving the vaccine, including their consent to be vaccinated.

5. Patient Group Directions (PGDs) and Patient-Specific Directions (PSDs): These are guidelines that outline the authorized protocols for administering the yellow fever vaccine. PGDs provide instructions for vaccinating groups of patients, while PSDs are personalized instructions for individual patients who might require specific considerations during vaccination.

Adhering to these guidelines on clinical procedures ensures the proper administration, documentation, and monitoring of yellow fever vaccination, thus contributing to effective vaccination campaigns and increased public health protection.

Is there a link between thymoma and yellow fever vaccination?

Title: Investigating the Link between Thymoma and Yellow Fever Vaccination

Introduction:
The article titled “History of thymoma and yellow fever vaccination” by Barwick Eidex R. presents a study conducted by the Yellow Fever Vaccine Safety Working Group. This investigation aims to determine whether there is a connection between thymoma, a tumor of the thymus gland, and the administration of the yellow fever vaccine. The Lancet published this study in 2004.

Study Focus:
The purpose of the study was to assess whether there is evidence to support a link between thymoma and yellow fever vaccination. Thymoma is a rare type of tumor derived from the thymus gland, located in the chest, near the heart. On the other hand, yellow fever is a viral disease that can cause symptoms ranging from mild to severe, potentially leading to organ failure and death.

Methodology:
The Yellow Fever Vaccine Safety Working Group conducted a comprehensive investigation using various methodologies. The researchers reviewed medical records and gathered data from individuals who had a previous history of thymoma and had received the yellow fever vaccine. These records were analyzed to identify any potential patterns, correlations, or adverse effects.

Results:
The Lancet article does not directly mention the specific findings of the study. However, it implies that the researchers did not find sufficient evidence to establish a firm link between thymoma and yellow fever vaccination. The lack of a direct mention may suggest that the study did not identify any significant relationship between the two factors. Nonetheless, a more detailed examination of the full article is necessary for a more comprehensive understanding of the study’s findings.

Conclusion:
Based on the available information from the Lancet article, it is inconclusive whether there is a definite link between thymoma and yellow fever vaccination. Further research may be required to explore this possible connection in more detail and provide a clearer understanding of any potential risks associated with yellow fever vaccination in individuals with a history of thymoma.

Are there any reported adverse events following yellow fever vaccination?

Yes, there have been reported adverse events following yellow fever vaccination. Several studies have documented cases of adverse events associated with yellow fever vaccination. One study published in the Journal of Travel Medicine in 2016 examined adverse event reports between 2007 and 2013. Another study published in Vaccine in 2007 described 15 cases of neurologic disease associated with yellow fever vaccination. Similarly, a study published in the American Journal of Tropical Medicine and Hygiene in 2009 focused on the incidence of yellow fever vaccine-associated neurotropic disease. Furthermore, the Centers for Disease Control and Prevention has also documented adverse events associated with yellow fever vaccination in the United States.

When was the information published and last updated?

The information in Excerpt_Theirs was initially published on January 14, 2020. It was last updated on February 6, 2024.

Can yellow fever and measles, mumps, and rubella vaccines be administered on the same day?

According to the provided information, it is not recommended to administer yellow fever vaccine and measles, mumps, and rubella (MMR) vaccine on the same day. It is advised to maintain a minimum interval period of four weeks between the administration of these two vaccines. This is because co-administering yellow fever and MMR vaccines may result in sub-optimal antibody responses to yellow fever, mumps, and rubella antigens. In cases where immediate protection is required, the vaccines can be given at any interval; however, it is suggested to consider an additional dose of MMR. Re-vaccination with yellow fever vaccine can be considered for individuals with ongoing risk on a case-by-case basis.

Is there a genetic predisposition for YEL-AVD or YEL-AND?

Currently, there is a lack of sufficient evidence to conclusively determine if there are specific genetic risk factors that make individuals more susceptible to serious adverse reactions such as Yellow Fever-Associated Viscerotropic Disease (YEL-AVD) or Yellow Fever-Associated Neurologic Disease (YEL-AND). Further research is required to fully explore this area. Until additional information becomes available, it is advised to refrain from administering the Yellow Fever (YF) vaccine to individuals who have a first-degree family history (parent, full sibling, or child) of YEL-AVD or YEL-AND that cannot be attributed to a known medical risk factor. This precaution is especially important in cases where there is an unidentified genetic predisposition.

What are the additional risk factors for serious adverse events following yellow fever vaccination?

There are certain risk factors that increase the likelihood of serious adverse events following yellow fever vaccination. One such risk factor is having a thymus disorder or undergoing thymectomy (removal of the thymus gland) for any reason. Individuals with such medical history should never be administered the yellow fever vaccine. It should be noted that certain cardiac surgical procedures may also involve unintentional thymectomy, presenting an additional risk factor.

Should older travelers visiting low-risk areas for yellow fever be vaccinated?

According to the World Health Organization (WHO), it is generally not recommended for individuals aged 60 years or older to receive the yellow fever vaccine when traveling to areas that are classified as having a low potential for exposure to the virus. These low-risk areas are those where yellow fever vaccination is generally not advised.

These areas should be considered as having a minimal or negligible risk of contracting yellow fever. As a result, older travelers visiting these low-risk areas may not need to be vaccinated against yellow fever since the probability of exposure is deemed insignificant and avoidable.

It is important for individuals to stay informed about the specific recommendations provided by the WHO regarding yellow fever vaccination and the risk levels associated with different geographical areas. This allows for informed decision-making regarding the necessity of vaccination, particularly for older individuals who may have different health considerations.

Who is at a higher risk for YEL-AVD?

Individuals who are 60 years and older are at a higher risk for YEL-AVD (Yellow Fever Vaccine-Associated Viscerotropic Disease). The risk of experiencing serious adverse events related to YEL-AVD increases as individuals enter this age group. Specifically, the risk is approximately 1.2 cases per 100,000 doses distributed for those aged 60 and older. Furthermore, the risk becomes even higher for individuals who are 70 years and older, although the specific data for this age bracket is not provided in the given excerpt.

What is the case-fatality ratio for YEL-AVD?

The case-fatality ratio for YEL-AVD is approximately 48 percent in the United States, while globally, more than 60 percent of reported YEL-AVD cases have resulted in death.

How does YEL-AVD manifest in patients?

YF vaccine-associated viscerotropic disease (YEL-AVD) is a syndrome that presents with fever and multi-organ failure, resembling severe yellow fever (YF) disease. It was first documented in 2001 and has been reported in numerous cases worldwide. In the United Kingdom, there have been a total of five reported cases, occurring in 1998, 2000, 2018, and 2019.

Patients typically develop symptoms of YEL-AVD within one to eighteen days following vaccination, with a median onset of around four days. Initial symptoms include fever, malaise, headache, and myalgia. As the disease progresses, individuals may experience inflammation of the liver (hepatitis), low blood pressure (hypotension), and ultimately, multi-organ failure.

Unfortunately, the reported mortality rate for YEL-AVD cases is high, with more than 60 percent of cases worldwide resulting in death. In the United States, the case-fatality ratio for all reported YEL-AVD cases is approximately 48 percent.

What are the recommendations for individuals aged 60 years or older?

Individuals aged 60 years and older are advised to carefully consider the countries and areas designated by the World Health Organization (WHO) as having a low potential for exposure to the yellow fever virus. It is highly recommended for individuals in this age group to consult the WHO’s guidelines regarding safe travel destinations. Taking into account the potential risks associated with yellow fever, it is crucial for older individuals to prioritize their health and well-being when planning their travels.

What methods can be used to prevent YF, including vaccination and mosquito control?

To prevent yellow fever (YF), there are various methods that can be employed, including vaccination and mosquito control.

Vaccination is a highly effective method to prevent yellow fever and has been available for over 70 years. It is recommended for individuals who are at risk of yellow fever infection. Before administering the vaccine, it is important to consider any contraindications and precautions based on the individual’s specific risk assessment. For individuals aged 60 years or older, the vaccine should only be given when there is a significant and unavoidable risk of acquiring yellow fever, such as traveling to areas with current or periodic transmission.

For those who travel to countries or areas with a risk of yellow fever transmission but have not been vaccinated, it is crucial to be aware of the potential of contracting yellow fever. Therefore, it is advised to adopt meticulous measures to avoid mosquito bites. These measures should be followed by all travelers in order to minimize the risk of yellow fever infection.

How is YF diagnosed and treated?

Yellow fever (YF) diagnosis and treatment primarily involve assessing the clinical symptoms, travel history, and activities of the patient. When a healthcare professional suspects YF in a person who has recently returned from traveling, it is crucial to promptly refer them to a specialized infectious disease or tropical disease clinical team. In the United Kingdom, the UK Health Security Agency’s Rare and Imported Pathogens Laboratory serves as a specialist center that offers expert advice and diagnosis for various uncommon viral and bacterial infections, including yellow fever.

To diagnose yellow fever, healthcare professionals rely on several factors. They carefully examine the patient’s clinical features, considering symptoms like fever, headache, muscle pain, nausea, and jaundice. Additionally, they take into account the individual’s travel history, especially if they have been to regions known for yellow fever transmission. The dates of travel and specific activities during the trip are also assessed.

Once yellow fever is suspected, an urgent referral to the infectious disease or tropical disease clinical team is made. These specialized healthcare providers possess the knowledge and expertise required for accurate diagnosis. They may conduct specific tests, including blood tests, to confirm the presence of the yellow fever virus.

When it comes to treatment, there is currently no specific antiviral therapy available for yellow fever. Therefore, supportive care becomes the focus. Healthcare professionals aim to alleviate the symptoms and complications associated with the disease. Supportive care typically involves maintaining hydration, providing pain relief, controlling fever, and managing other medical conditions that may arise as a result of the infection.

In severe cases, hospitalization may be necessary to closely monitor the patient’s condition and ensure appropriate medical intervention. Critical care measures, such as intravenous fluids and respiratory support, may be administered to stabilize the patient.

Prevention plays a significant role in managing yellow fever. Vaccination is considered the most effective preventive measure against this viral disease. Travelers to areas at risk for yellow fever transmission are advised to receive the yellow fever vaccine before their trip. Strict adherence to mosquito bite prevention measures, such as using insect repellents and wearing protective clothing, can also help reduce the risk of contracting yellow fever.

In conclusion, the diagnosis of yellow fever relies on assessing the patient’s clinical features, travel history, and activities. Prompt referral to specialized infectious disease or tropical disease clinical teams is crucial for accurate diagnosis. Currently, there is no specific antiviral treatment available for yellow fever, so supportive care is used to manage symptoms and complications. Prevention through vaccination and mosquito bite prevention measures is key in controlling the spread of yellow fever.

What are the signs and symptoms of YF infection and how does the severity vary?

Yellow fever (YF) infection presents with a range of symptoms, which can vary in severity. After being bitten by an infected mosquito, there is an incubation period of three to six days before symptoms develop. Initial signs of YF infection include muscle pain (myalgia), high temperature (pyrexia), headache, lack of appetite (anorexia), nausea, and vomiting. Fortunately, for many patients, these symptoms improve and gradual recovery is observed within three to four days from the onset of symptoms.

However, in some cases, approximately 15 to 25 percent of patients experience a progression into a more severe form of the illness within 24 hours of apparent recovery. This advanced stage is known as acute haemorrhagic fever and is characterized by several alarming manifestations. Patients may experience bleeding from various areas such as the mouth, eyes, ears, and stomach. Jaundice, marked by yellowing of the skin, is also a significant symptom and is responsible for giving the disease its name. Additionally, YF infection can cause damage to the kidneys (renal) and result in shock and deterioration of major organ function. Unfortunately, the mortality rate for this severe form of YF infection ranges from 20 to 50 percent, with a significant portion of patients not surviving.

It is important to note that recovery from YF infection provides lifelong immunity to those who overcome the illness.

How is the YF virus transmitted and what are the different transmission cycles?

Yellow fever (YF) virus is transmitted through three distinct cycles:

1. Jungle Cycle: The jungle cycle of transmission primarily takes place in the tropical rainforests of Africa and South America. This transmission involves interactions between monkeys and jungle breeding mosquitoes. The virus circulates between these two hosts, with humans at risk of infection when they live or work in areas where this cycle occurs.

2. Savannah Cycle (Africa only): The savannah cycle occurs in the moist savannah regions of Africa, where humans coexist closely with monkey populations. The transmission cycle involves interactions between monkeys and humans, primarily transmitted through Aedes spp. mosquitoes. These mosquitoes act as the vector responsible for spreading the virus from infected monkeys to humans.

3. Urban Cycle: In the urban cycle, the YF virus can spread to urban areas from individuals infected during the jungle cycle. This transmission occurs when infected humans introduce the virus to densely populated urban areas. The spread of the virus in urban settings primarily depends on transmission between humans through the domesticated mosquito vector, Aedes aegypti. These mosquitoes breed in close proximity to human habitation and facilitate the transmission of the virus from infected individuals to others.

In summary, the YF virus is transmitted through the jungle cycle involving interactions between monkeys and jungle breeding mosquitoes, the savannah cycle involving interactions between monkeys and humans through Aedes spp. mosquitoes, and the urban cycle where the virus spreads between humans facilitated by Aedes aegypti mosquitoes.

What options are available for individuals who cannot receive YF vaccination for medical reasons?

Individuals who are unable to receive the yellow fever (YF) vaccination for medical reasons, including infants under 6 months of age, have an alternative option available. In such cases, an authorised health worker, such as the YFVC Responsible Supervising Clinician (RSC), a nurse or pharmacist working at the YF vaccination centre, or another licensed health professional overseeing the medical care of the individual can issue a Medical Letter of Exemption (MLoE) from vaccination. This MLoE serves as documentation stating that due to specific medical reasons, the individual is contraindicated from receiving the YF vaccination.

Can valid certificates of YF vaccination be rejected based on the time that has passed since vaccination?

According to the World Health Organization (WHO), it is not permissible to reject valid certificates of Yellow Fever (YF) vaccination based on the duration that has passed since the vaccination was effective, as stated on the certificate. The WHO explicitly states that vaccination certificates cannot be rejected on the grounds that more than ten years have elapsed since the effective date mentioned on the certificate. Furthermore, it is important to note that requiring boosters or revaccination for YF cannot be mandated by authorities.

What is the treatment for yellow fever and what is the outlook?

The treatment for yellow fever involves comprehensive supportive care within a hospital setting. Patients are carefully attended to by medical professionals who focus on managing symptoms and bolstering the immune system’s response. This includes providing essential fluids, administering oxygen, maintaining blood pressure, offering blood transfusions, and, if necessary, initiating dialysis. Concurrently, any secondary infections are promptly treated, and the patient is vigilantly monitored throughout the course of their illness. Regrettably, there is no specific antiviral medication available for yellow fever, emphasizing the importance of symptom management and immune support measures. Patients are strongly advised against the use of certain painkillers, such as aspirin, to mitigate the risk of internal bleeding. As for the outlook, the prognosis for individuals with yellow fever varies significantly. Those who progress to the toxic stage face a heightened mortality risk, with statistics indicating a range of 20 to 50 percent facing the potential of death within a two-week timeframe. Therefore, constant monitoring and attentive care are paramount, underscoring the critical significance of preventing further disease transmission by avoiding mosquito bites.

How is yellow fever diagnosed and what are the possible complications?

Yellow fever is diagnosed based on symptoms, recent travel history to at-risk areas, and laboratory tests. Seeking prompt medical attention is crucial if there are signs of an allergic reaction following vaccination or if severe symptoms of yellow fever develop. Common symptoms of yellow fever include headache, fever, joint and muscle aches, nausea, vomiting, loss of appetite, and fatigue. In severe cases, patients may enter the toxic stage with more serious symptoms. Complications of yellow fever can be fatal, with almost half of patients showing severe symptoms dying within 1-2 weeks. Management involves controlling symptoms and supporting the immune system of patients. It is important to seek medical attention promptly if there are signs of an allergic reaction after vaccination or if severe symptoms of yellow fever develop.
Exams and Tests: The health care provider will perform a physical examination and order blood tests. These blood tests may show liver and kidney failure and evidence of shock. It is important to tell your provider if you have traveled to areas where the disease is known to thrive. Blood tests can confirm the diagnosis.
Possible Complications: Complications that may result include coma, death, disseminated intravascular coagulation (DIC), kidney failure, liver failure, salivary gland infection (parotitis), secondary bacterial infections, and shock.

What is yellow fever and how is it transmitted?

Yellow fever is a mosquito-borne disease. It’s called yellow fever because of symptoms including yellowing of skin (jaundice) and high fever. The yellow fever virus is most common in the tropical areas of Africa and Central and South America. Yellow fever is a viral infection that is primarily spread through the bites of infected mosquitoes carrying the virus. When a person is bitten by a mosquito infected with the yellow fever virus, they can develop this disease. It is important to note that yellow fever is prevalent in specific regions, notably South America and sub-Saharan Africa

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