Yellow Fever

Yellow fever is a serious and potentially fatal viral disease transmitted through the bite of infected mosquitoes.  It is found in tropical and subtropical regions of Africa and South America, where it poses a significant risk to unvaccinated travellers.  While yellow fever is rare in returning UK travellers, the consequences of infection can be severe, and in some cases the disease can progress rapidly to a life-threatening illness.

Vaccination is the single most effective way to protect yourself against yellow fever.  Unlike many other travel vaccines, the yellow fever vaccine is a legal entry requirement for a number of countries – meaning that without proof of vaccination, you may be refused entry at the border.  Jasins Pharmacy in Hounslow is a designated yellow fever vaccination centre, authorised to administer the vaccine and issue the official International Certificate of Vaccination or Prophylaxis (ICVP).

 

How Yellow Fever Spreads

Yellow fever is caused by the yellow fever virus, a flavivirus transmitted to humans through the bite of infected Aedes and Haemogogus mosquitoes.  Unlike some other mosquito-borne diseases, yellow fever cannot be spread directly from person to person – it requires a mosquito as an intermediate host.

Yellow fever transmission occurs in three distinct settings:

• Sylvatic (jungle) yellow fever – transmitted in tropical rainforests by mosquitoes that have fed on infected primates, primarily affecting forestry workers and those in rural areas
• Intermediate yellow fever – occurs in humid or semi-humid parts of Africa, where mosquitoes infect both humans and monkeys living in close proximity
• Urban yellow fever – the most widespread form, occurring in densely populated areas where the Aedes aegypti mosquito spreads the virus between humans

 

Travellers are at risk in affected regions of sub-Saharan Africa and tropical South America, particularly those spending time outdoors, in rural or forested areas, or in regions with limited mosquito control measures.

 

Symptoms of Yellow Fever

Symptoms of yellow fever typically appear three to six days after a bite from an infected mosquito.  Yellow fever can vary greatly in severity – some people experience only a mild illness, while for others it can become rapidly life-threatening.

Initial symptoms include:

• Sudden onset of high fever
• Severe headache
• Back pain and muscle aches
• Loss of appetite and nausea
• Vomiting
• Fatigue and general weakness

 

Most people recover fully after this initial phase.  However, approximately 15% of those infected enter a more severe toxic phase within 24 hours of apparent recovery.  This second phase is characterised by the return of high fever, jaundice (yellowing of the skin and eyes – from which the disease gets its name), abdominal pain, vomiting, and bleeding from the mouth, nose, eyes, or stomach.  Around half of those who enter the toxic phase do not survive.

There is no specific antiviral treatment for yellow fever, which makes vaccination the only reliable form of protection.

 

The Yellow Fever Vaccine

The yellow fever vaccine (Stamaril) is a highly effective live attenuated vaccine that provides long-lasting protection against the yellow fever virus.  It is given as a single injection, and in the vast majority of people, a single dose provides lifelong immunity.

• Single dose – one injection provides protection for life for most healthy individuals
• Timing – the vaccine should ideally be given at least 10 days before travel to allow full immunity to develop
• Certificate validity – the International Certificate of Vaccination or Prophylaxis (ICVP) becomes valid 10 days after vaccination and is valid for life
• Booster doses – may be recommended for certain at-risk groups, including those travelling to high-risk areas with ongoing outbreaks; your pharmacist will advise

 

Because the yellow fever vaccine is a live vaccine, it is not suitable for everyone.  It is generally not recommended for infants under nine months, pregnant women, people aged 60 and over travelling to high-risk areas, and those who are immunocompromised.  A travel health consultation is essential to confirm suitability before the vaccine is administered.

 

Which Countries Require the Yellow Fever Vaccine?

The yellow fever vaccine is a mandatory entry requirement for a number of countries, and proof of vaccination may also be required when travelling from a yellow fever endemic country to a non-endemic one.  Requirements can change, so it is important to check the latest guidance for your specific destination before you travel.

Countries and regions where yellow fever vaccination is commonly required or strongly recommended include:

• Sub-Saharan Africa, including Nigeria, Ghana, Kenya, Uganda, and the Democratic Republic of Congo
• Tropical South America, including Brazil, Peru, Colombia, Bolivia, and Ecuador
• Parts of Central America and the Caribbean
• Some countries in Southeast Asia require proof of vaccination if arriving from a yellow fever endemic country

 

A travel health consultation can confirm exactly which vaccinations and documentation are required for your destination, including whether a yellow fever certificate is mandatory for entry.

 

Who Should Consider the Yellow Fever Vaccine?

The yellow fever vaccine may be recommended or required for:

• Travellers visiting countries in sub-Saharan Africa or tropical South America
• Those travelling to countries that require proof of vaccination as a condition of entry
• Travellers spending time outdoors, in rural areas, or in regions with limited mosquito control
• Long-term travellers or those undertaking humanitarian or fieldwork in endemic regions
• Travellers transiting through yellow fever endemic countries, depending on destination entry requirements

Even if vaccination is not a legal requirement for your destination, it may still be strongly recommended based on the activities you have planned and the areas you intend to visit.  Our pharmacists will review your travel itinerary and provide personalised advice during your consultation.

 

Possible Side Effects

The yellow fever vaccine is generally safe and well tolerated in healthy adults.  As with all vaccines, some people may experience mild side effects following vaccination.

Possible side effects include:

• Soreness, redness, or mild swelling at the injection site
• Headache
• Mild fever
• Muscle aches
• Fatigue

 

These symptoms are usually mild and resolve within a few days.  Serious adverse reactions are rare but can occur, particularly in older adults and those with weakened immune systems – which is why a pre-vaccination consultation is essential.  Very rarely, a serious condition called yellow fever vaccine-associated viscerotropic disease (YEL-AVD) can occur, particularly in people over 60.  Your pharmacist will discuss any contraindications or risk factors with you before proceeding.

 

Frequently Asked Questions

What is yellow fever?

Yellow fever is a serious viral disease transmitted through the bite of infected mosquitoes, found in tropical and subtropical regions of Africa and South America.  It can progress from a mild illness to severe, life-threatening condition characterised by jaundice, organ failure, and bleeding, and there is no specific antiviral treatment available.

Do I need a yellow fever certificate to travel?

Many countries in Africa and South America require proof of yellow fever vaccination as a condition of entry, and some countries outside endemic zones require it if you are arriving from an endemic country.  You should always check the entry requirements for your specific destination well in advance of travel, as requirements can change.

How long does the yellow fever vaccine last?

For most healthy individuals, a single dose of the yellow fever vaccine provides lifelong protection, and the International Certificate of Vaccination or Prophylaxis (ICVP) is now valid for life.  Booster doses may be recommended for certain groups, including those who were vaccinated during pregnancy or who are travelling to areas with ongoing outbreaks – your pharmacist will advise.

Where can I get the yellow fever vaccine?

The yellow fever vaccine must be administered at a registered yellow fever vaccination centre – only designated centres are authorised to issue the official ICVP certificate.  Jasins Pharmacy in Hounslow is a registered yellow fever centre and can administer the vaccine and issue your certificate on the day of your appointment.

Who cannot have the yellow fever vaccine?

The yellow fever vaccine is a live vaccine and is not suitable for everyone.  It is generally not recommended for infants under nine months of age, pregnant women, people who are immunocompromised, and those with a history of thymus disease.  Adults aged 60 and over travelling to high-risk areas should also receive careful assessment before vaccination, as the risk of rare serious reactions increases with age.

Are there side effects from the yellow fever vaccine?

Most people tolerate the yellow fever vaccine well.  Mild side effects such as soreness at the injection site, headache, mild fever, and fatigue are possible and usually resolve within a few days.  Serious reactions are rare but can occur, particularly in older adults or those with underlying health conditions, which is why a pre-vaccination consultation is always carried out before the vaccine is given.

 

Your Trip Starts with Staying Safe

Whether yellow fever is a health risk at your destination or a mandatory entry requirement, getting vaccinated at a registered centre before you travel is non-negotiable.  Book a travel health consultation at Jasins Pharmacy in Hounslow today – our team will ensure you have everything you need to travel safely and confidently.